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Meeting the Challenge of the Nineties:

Proceedings,
Intermountain Forest Nursery

Assocption

—1

August 10-14^T987
Oklahoma City^ Okla^ma

Landis, Thomas D. 1987- Meeting the challenge of the nineties: proceedings,
Intermountain Forest Nursery Association; I987 August 10-l4; Oklahoma City,
OK. Gen. Tech. Rep. RM-I5I. Fort Collins, CO: U.S. Department of Agriculture,
Forest Service, Rocky Mountain Forest and Range Experiment Station. I38 p.

Abstract

This proceedings is a compilation of 27 articles on various phases of forest
nursery management. Specific topics include: seed treatments, soil management,
cultural practices, seedling quality, and nursery pests. Results of a
discussion on the nursery competition issue are also presented.

NOTE

As part of the planning for this symposium, we
decided to process and deliver these proceedings to
the potential users as quickly as possible. To do this,
we asked each author to assume full responsibility for
submitting reviewed manuscripts in photoready format
within tight deadlines. Thus the manuscripts did not
receive conventional Forest Service editiorial processing,
and consequently, you may find some typographical errors
and slight differences in format. We feel quick publication
of the proceedings is an essential part of the symposium
concept and far outweighs these relatively minor distractions.
The views expressed in each paper are those of the author
and not necessarily those of the sponsoring organizations.
Trade names are used for the information and convenience
of the reader, and do not imply endorsement or preferential
treatment by the sponsoring organizations.

USDA Forest Service

General Technical Report RM-151

December, 1987

Meeting the Challenge of the Nineties:
Proceedings,

Intermountain Forest Nursery
Association

August 10-14, 1987
Oklahoma City, Oklahoma

Technical Coordinator:

Thomas D. Landis
Western Nursery Specialist
Pacific Northwest Region
USDA Forest Service

Rocky Mountain Forest and Range

Experiment Station
Forest Service

U.S. Department of Agriculture
Fort Collins, Colorado

Funding for this publication was provided by
State and Private Forestry, USDA Forest Service.

Contents

Seedlings, Service, and Insights 1

Carl E. Whitcomb

Communications as a Design Consideration in Developing a Computerized Nursery

Management Environment 3

John R. South

Applications of Portable Data Recorders in Nursery Management and Research 9

W. J. Rietveld and Russell A. Ryker

Superabsorbent Hydrogels and Their Benefits in Forestry Applications 14

Fernando Erazo

Organic Matter: Short-Term Benefits and Long-Term Opportunities 18

John G. Mexal and James T. Fisher

The Trees Unlimited Program: An Experiment in Establishing Seedling Plantings 24

Robert C. Oswald

The Potential of Soil Solarization in Nurseries to Control Soilborne Diseases 27

Kenneth E. Conway

Seedling Production at Oklahoma Forestry Division Forest Regeneration Center 30

Clark D. Fleege

Priming Treatments to Improve Pine Seed Vigor 33

S. W. Hallgren

Effects of Nursery Density on Shortleaf Pine 36

John C. Brissette and William C. Carlson

Polymeric Nursery Bed Stabilization to Reduce Seed Losses in Forest Nurseries 42

William C. Carlson, John G. Anthony, and R. P. Plyler

Improving Outplanting Survival of Stored Southern Pine Seedlings by Addition of Benomyl

to the Packing Medium 43

James P. Barnett and John C. Brissette

Measuring Tree Seed Moisture Content Now and in the Future 46

Robert P. Karrfalt

Forest Tree Nursery Herbicide Studies at the Oklahoma Forest Regeneration Center 49

Lawrence P. Abrahamson

Use of Sulfur to Correct Soil pH 58

Donald H. Bickelhaupt

Certified Vendor Program 66

Thomas G. Boggus

Alternative Methods to Evaluate Root Growth Potential and Measure Root Growth 70

W. J. Rietveld and Richard W. Tinus

Comparison of Time and Method of Mist Chamber Measurement of Root Growth Potential 77

Karen E. Burr, Richard W. Tinus, Stephen J. Wallner, and Rudy M. King

Effects of Lift Date, Storage, and Family on Early Survival and Root Growth Potential of Shortleaf Pine 87
S. W. Hallgren and C. G. Tauer

Fall Lifting: Its Effects on Dormancy Intensity of Ponderosa Pine Seedlings — A Preliminary

Investigation 93

Steven K. Omi and Ursula K. Schuch

A Status Report on Nursery and Reforestation Projects at the Missoula Technology and

Development Center 98

Ben J. Lowman

Grading Pine Seedlings with Machine Vision 100

Glenn A. Kranzler and Michael P. Rigney

Mycorrhizae Nursery Management for Improved Seedling Quality and Field Performance 105

Charles E. Cordell, Jeffrey H. Owen, and Donald H. Marx

Integrated Pest Management in Forest Nurseries 116

T. H. Filer, Jr. and C. E. Cordell

The USFS Reforestation Improvement Program 120

W. J. Rietveld, Peyton W. Owston, and Richard G. Miller

Government vs Private Nurseries: The Competition Issue 126

Thomas D. Landis

Working Group Sessions on Communications and the Government/Private Nursery Issue 130

Session I: Communications
Session II: Government vs Private Nurseries
Kurtis L. Atkinson

Minutes of the Annual Business Meeting 1 34

List of Attendees 135

iii

Seedlings, Service, and Insights^

Carl E. Whitcomb^

INTRODUCTION

Bed-grown tree seedlings have been produced
for many years with variable performance at out-
planting. Slowly, container-grown seedlings have
gained in popularity in spite of their higher cost
But what about the future? Here is one practical
research/practioner ' s outlook.

Over the years much of the variability among
seedlings has been attributed to genetics. If 100
viable seeds of most species are planted in a seed
bed, the resulting seedlings generally grow at
different rates. Container-grown seedlings are
generally somewhat less variable. This slight
improvement in uniformity is mostly attributed to
more precise control of cultural conditions.

In the fall of 1985 the opportunity arose to
examine the roots of 720 trees, 180 each of four
species: lacebark elm, UlmiU> poAV i.{^0 Lia) shumard
oak, QaoAcvu, ikwmoAcli; loblolly pine, ?A.n.uu,
tCLQ-da; and Chinese pistache, ?AJ>tacMi ckimnA-U, .
They had been grown in bottomless milk carton
containers for approximately three months, then
transplanted into two-gallon poly bag containers
for the remainder of the first growing season and
planted into the field in October. There were
approximately 500 seedlings of each species in
the poly bags from which the most uniform 180 were
selected to minimize genetic variability. After
two growing seasons in a sandy clay loam soil of
moderate fertility, some trees had grown very
little, while others exceeded nine feet in height
and two-inch stem diameter. Could all of this
variation be due to genetics or was something
else involved?

Three days were required to excavate the 720
trees with a backhoe. All of the larger trees had
large root systems but was this a factor of gene-
tics? Counts of roots 3/4-inch in diameter or
larger were poorly correlated with tree size.
Counts of roots at a point approximately 12 inches
from the stem were also poorly correlated with
tree size. However, when counts of roots approxi-
mately 1/8-inch in diameter or larger arising

from the root/stem interface were taken, a strik-
ing correlation resulted (Figure 1). Only data
and photo of the lacebark elm are included, since
all four species responded similarly.

" 1 i 1 1 1 1 1

0 10 20 30 40 50 60 70

Number of roots/tree 4 mm diameter or larger

Figure 1. Relationship of number of roots arising
from the root/stem interface and stem diameter
of lacebark elm.

These data suggest that where the roots
branch is very important and that this may be a
major factor affecting the rate of tree growth.
Thus, a genetically superior tree with a poor root
system may only grow at a slow to moderate rate.

A NEW CONTAINER

To utilize this information, a unique new
propagation container was designed. Called the
Root Maker (U.S. and other patents pending), this
container is 2.6 inches square and four inches
deep and air-prunes the root system both at the
bottom and on the sides (Figure 2) . The bottom
is shaped somewhat like a pyramid so that the tap-
root and any secondary roots that reach the bottom
will be air-pruned at one of four drain holes.
Secondary roots that grow outward are guided to
air-pruning openings in the sides. The four-inch
depth forces secondary root branching at, or near,
the base of the stem. Individual containers lock
into a frame for ease of filling and handling and
to insure proper spacing, yet can be easily removed
for shipping or planting.

This data also suggests that bed-grown seed-
Ipaper presented at the 1987 meeting of the lings should be root-pruned early and perhaps

Intermountain/Great Plains Nursery Association. often. A wider spacing will also be necessary to

accommodate more lateral roots.

•^Carl Whitcomb is Research Horticulturist
with Lacebark Research, Rt . 5, Box 174, Stillwater,
Oklahoma 74074

Figure 2. The Root Maker container air root-
prunes tree seedlings on the sides as well as at
the bottom. In addition, by controlling the
depth, the root system is forced to branch at the
root/stem interface to enhance tree growth.

NUTRITION

Proper nutrition can enhance plant growth
and health and minimize other problems. The key
is the synchronization of all of the essential
elements. Studies with container-grown seedlings
suggest that nitrate nitrogen, phosphorus, and
the micronutrients are key factors.

Seedlings appear to have a limited capacity
to utilize ammoniacal nitrogen, but do respond to
nitrate. Phosphorus is very important. Potassium
can vary considerably without affecting growth.
The micronutrients play a key role in enhancing
overall plant health and stem and root develop-
ment. They can be added to the mix using research-
formulated blends such as Micromax micronutrients
that also provide sulfur.

The two major nutritional variables that are
unique to each specific production site are calcium
and magnesium. If pine bark or other wood product
is used as a component of the growth medium, it
should be analyzed for calcium and magnesium.
However, the analysis must be done using an
ammonium acetate extract to determine the levels
available to the plant. Water extracts show only
what will readily leach out. Strong acid extracts
give inflated values due to partial or complete
destruction of the particles.

Water quality is a variable that must be

considered in the production of both container and
field production of seedlings. The levels of
calcium and magnesium in the irrigation water play
a key role in plant nutrition. In some cases,
the irrigation water provides all of the calcium
and magnesium needed. Other water provides only
calcium, thus requiring a separate magnesium
source. In the future, a water analysis plus
growth medium analysis will be used to determine
the levels of calcium and magnesium needed for
optimum plant growth.

A related point is that the pH of the water
gives little information regarding water quality.
The pH gives only a measure of the acidity or
alkalinity of the water, nothing more. A water
may have a pH of 6 and contain considerable
calcium or a pH of 9 and contain very little. A
complete water analysis is the only way to know.
Water with a high pH generally contains consider-
able bicarbonate which, if above about 200 ppm,
must be considered in the nutritional program.

Bed-produced seedlings are affected by
irrigation water quality as well. Due to the
strong buffer of most soils, a longer time is
generally required before the effects are noticed.
Most soils labs suggest that a soil pK of 6 to 7
is ideal. This may be true for fast-growing annual
crops such as corn, wheat, and soybeans, but it
is not correct for trees. More precise management
of this area as it affects nutrition will be
required in the future.

Improved root systems in combinations with
improvements in the entire water quality/nutrition
complex and established good cultural practices
will dramatically improve tree health, transplant
success and subsequent growth. More precise
production techniques will require more accurate
monitoring by nursery managers. However, the
payoff will be a superior product that requires
fewer pesticides and is more uniform. The
increased uniformity will allow further mechani-
zation and labor savings. It all starts with the
root system but the roots must be supplied with a
precise nutritional program to maximize growth.

LITERATURE CITED

Whitcomb, Carl E. 1987. Establishment and

Maintenance of Landscape Plants. 618 p.

Lacebark Publications, Stillwater, OK.
Whitcomb, Carl E. 1987. Production of Landscape

Plants. 487 p. Lacebark Publications,

Stillwater, OK.

Communications as a Design Consideration
in Developing a Computerized Nursery
IVIanagement Environment^

John R. South'

Abstract: The transition from a manual to a computerized
is successful only if the designers consider three levels
of communications in the social and technical environments.
In order of importance, these levels include communications
among the staff members, communications between the staff
and the computer, and communications between computers.

INTRODUCTION

The purpose of this paper is to examine how
three levels of communications have played an
important part in the development of the nursery
management tool for Oklahoma. The three levels
are:

- communications between members of
staff,

- communications between the staff
and the computer,

- communications between the various
computers in the operation.

Consideration of the levels of communication
has developed from the observation that the
office environment is often viewed by management
as being split between social and technical
considerations. The author contends that, if the
manager of a nursery wants to successfully
convert from a manual to an automated operation,
all three levels of communication must be
cons idered.

COMMUNICATIONS BETWEEN STAFF MEMBERS

The 'traditional' manner of software
development has been for the software designers
to meet with the managers and supervisors of a
particular operation and decide among themselves
what software is needed to automate an office.
The staff workers are not brought into the

picture until after the development process has
been completed. Their first view of the system
is when hardware and software are installed in
the office. The group at the Forest Regeneration
Center in Norman, Oklahoma have taken a quite
different approach to the development of their
system. From the first moment of development to
the present time, the staff has been deeply
involved in the definition of system
specifications, design of the work flow in the
system, and preliminary testing.

The most important role that the staff has
played has been that of an information filter.
The first meeting with the Oklahoma staff
revealed the vast amount of paper work that an
integrated nursery system would replace. In an
ideal system, one of the goals of the development
team is to filter the large amount of information
for superfluous and redundant data (fig. 1). The
members of the Oklahoma nursery have played that
role of informatiori filter.

I n forma t ion

Information Filter

1 Paper presented at the 1987 Intermountain
Forest Nursery Management Association Meeting.
Oklahoma City, August 10-13, 1987.

2 John South is the President of Personal
Computer Information Systems, Inc., Dallas, Tex.
and Indianapolis, Ind. PCIS is a firm which
specializes in software design, hardware sales
and installation, and office automation.

Figure I — The Nursery staff acts as the filter
which determines what information will be
be included in the automated system.

In addition to aiding in the design of the
system, previewing the information proposed for
inclusion in the automated operation has allowed
the staff to review the data that they have been

collecting in the past. This whole process of
bringing the staff into the design process has
had ramifications which should last long after
the automation process is complete.

when they sit in front of a computer for the
first time. Given incremental doses of
involvement with the computer helps to lessen the
apprehension these individuals feel.

Promotes a Spirit of Ownership

Bringing the staff into the development
process promotes a spirit of ownership in the
final product. This is important during the
conversion process.

In a typical conversion process, the manual
system runs parallel with the automated system.
This means that the nursery staff will have to
maintain both systems together for some specified
length of time. The period is trying at best,
but the path is much smoother when the staff
feels that they have had a significant impact on
the development of the product.

Provides a Creative Outlet

In the same light, including the staff in
the development process allows these individuals
to exercise their creative talents. It must be
remembered that these are the individuals who
have been performing the day-to-day tasks. Many
have 'ideas' as to how the data should be
collected, displayed, and reported. Involvement
in system development provides a job enrichment
unlike any normally available to the staff.

COMMUNICATION BETWEEN STAFF AND COMPUTER

The Integrated Environment

The Oklahoma Nursery Management System has
been designed as an integrated environment.
Though it does not encompass every function
encountered in the management of a nursery
operation, its operation does include most of
the major data-generating activities (fig. 2).

Lowers Resistance to Change

For long-term employees it may be difficult
to accept a new way of collecting and reporting
data, if an automated system is simply installed
without their input. In some cases, change is a
process that some staff members cannot accept;
however, involvement in this type of a project at
least gives the manager or supervisor an
opportunity to whittle away at the resistance.
Input from these long-term employees is important
to the project. There may be a reason why the
manual process should not be automated and this
reason needs to be heard.

Reduces Training Time

A great deal of resources in the form of
time and personnel may be needed to train
individuals in the operation of the automated
system. If these same individuals are part of
the, design process, they receive their training
in an evolutionary manner as the project
progresses. When they finish testing the final
process, management will find that very little
additional training will be necessary.

It is often seen that employees don't fear
the changing process as much they fear the new
technology. They are literally uncomfortable

Figure 2 The automated environment showing the
communication between the various submodules
and the main environment.

As Figure 2 implies, the integrated
environment was designed not only to bring all of
the data activities under 'one program', but more
importantly this type of configuration allows
each submodule to 'talk' to those submodules
which store data needed to complete a
calculation. This environment is not one program
but rather a number of programs 1 inked together
through a number of programming technigues. To
the user, the nursery staff member, the movement
from one submodule to the next is virtually
transparent .

Figure 3 illustrates the concept of one
submodule talking to another. In this case, the
Payroll module (which, as one of its functions,
collects information on cultural practices by
hours for each particular species) needs the
I'lames of the species which the nursery is
currently growing. So it 'asks' the Inventory
module which species are currently being grown.
On the other hand the Inventory module needs to
calculate the cost of growing a particular
species of seedling, so it 'asks' the Payroll
module how many hours and in what cultural

practices time was spent on a particular species.
Again, this transfer of information is totally
transparent to the user, but is maintained by
separate programs in the system.

Species Information

Hours Worked per Species

Figure 3 — Transfer of information between two
modules in the integrated environment.

A Dynamic Dialogue

Communications between the human staff
member and the computer is a dynamic process.
Interaction between the two entities changes from
one day to the next. The problem that faces the
system designer is that, once the program is
installed, the program is, in a sense, in a
static state. The process of moving from one
part of the program to another does not change
simply because it's Monday instead of Thursday.
But the data and the database are dynamic. They
are in a constant state of change.

Menus are the standard means of moving from
one point in a program to the next (fig. 4).
From the designers standpoint, menus are simple
to program and they present no particular
difficulty in error-checking. From the user's
standpoint, menus are simple to use, self-
aocumenting (to a point), and, in most cases,
ouite boring after the first few times though a
program.

It seems to be a step backwards to involve
your staff in the development of a computer
svstem (where you are trying to unleash their
creative talents), and then to saddle them withi a
system driven by one of the least creative
selection mechanisms. The Oklahoma system only
uses menus to move from one major program segment
to the next.

OKLAHOB* FORESTRY DIVISION
Nursery Hanageaent Systea

- Inventory Haln Henu

1) CheaicaJl Inventory

2) Seedling Inventory

3) Seed Inventory

4) Return to Haln Henu
3) Quit

Select Option

Data selection and data manipulation use one
of two mechanisms. In a database environment,
data records are selected by keys embedded in the
data. In some cases a key may be an employee's
name or social security number. In another case,
a key may be a particular species or species
code. In many cases, the key is a logical
representation of the character string which
actually retrieves the data. So the program must
prompt the human for the information it needs to
build the physical key. Figures 5 and 6 show two
methods that the Oklahoma system uses to prompt
the staff member for the necessary information to
bu i I d a key.

In the first case (fig. 5), the staff member
is using the Payroll submodule and is about to
add hours (specified by cultural practice) to an
employee's record. The individual entering the
data is using the employee's social security
number to pull up the employee's work history.
The social security number may have been the only
means the staff member hau of identifying the
employee, or the staff member may have felt that
using the social security number was a faster
means of getting to a particular employee's
record. The point should be made that using
either the name or the social security number of
thie employee would have led to the same record.
In thn's case, name and social security number are
alternative keys for a particular employee's
record.

OKLAHOHA FORESTRY DIVISION
Add Koure By Category

Enter Naae Or SSN

1) Laat Naae i

2) First Naae:

3) SSN: 111-11-1111

Enter The Beginning Date For Period Worked
4) Begin Date: 08/11/67

PRESS 'ESC TO GO TO MAIN MENU

Figure 5 -- Data selection through alternative
keys. The computer prompts the user for
the information needed to locate an
employee's record.

Though figure 5 appears somewhat like the
menus that were slandered above for their
inherent lack of creativity, the difference
between the two is that in using a key screen,
like that in figure 5, the staff member needs to
make decisions. The first decision is what key
to use. If an employee is not located using that
key, the user needs to decide what alternative
key to use to perform the search.

Figure 4 -- Menus are used only for movement from
one major program module to another.

Figure 6 illustrates another mechanism which
the Oklahoma system uses for gathering

information it needs for generating a key. The
user is in the Inventory module and wants to add
Ponderosa Pine to the species inventory. Rather
than flipping to a separate screen to ask for the
species name or species code, a window
automatically pops up on the screen indicating to
the user that the computer needs some information
before it can continue its processing. The
message in the bottom of the pop-up window
indicates that the user used the species name as
a key to the species' records. Since no species
record existed for Ponderosa Pine, the computer
indicates this fact and asks the user for the
species code in order to complete the initial
construction of the species record.

OKLAHOHA FORESTRY DIVISION
Species Addition Option

Enter Active Speclee

1) Speclee Name: Ponderosa Pine

2) Speclee Codes 11

Nev epeclee - please enter Species Code

PRESS 'ESC TO GO TO HAIM HENU

Figure 6 — A pop-up window which prompts the
user for information needed to construct
the key for new species record.

The final method the Oklahoma Nursery
Management system uses for obtaining a key to a
specific record is shown in figure 7. Again, the
pop-up window mechanism is used. In addition to
alerting the user to the fact that the computer
needs some piece of information, the pop-up
windows eliminate a number of screens and, in
some cases, a number of menus.

The difference in the case of figure 7 is
that the choices presented to the user are fed to
the pop-up window straight from the species
database. The user selects the species to update
by moving a cursor to the left of the number
corresponding to the species of interest. By
pressing the enter key, the selected species is
brought into active memory and is available to
the user for update.

Data Entry - A Model of Simplicity

Next to manipulating the data (producing
statistics and reports), the most important
function of any data processing system is
incorporating data into the database, i.e. data
entry. Many designers disagree on the level of
sophistication of a data entry screen; but, there
is no disagreement on the fact that data
validation is a primary concern of the system
designer. The integrity of the database is
protected only to the extent that the designers
provide for error checking when designing the
screens. There are two basic data entry screens
being used by the Oklahoma Nursery Management
System. A conventional screen (fig. 8) is used
for gathering most of the raw data for the
database records.

DKLAHOnA FORESTRY DIVISION
Personnel Update Option

1) Last Naae i South
21 First Nane: John R.

3) Address: 6909 Custer Road, #708

4) City 1 Piano

7) Phone Hu»beri (2141964-2670
9) Position: Area Forester

ill Area: CtW

13) Grade Step: 062-7

151 Start Date: 08/11/87

5) State: TX 6) Zip: 75023

8) Soc. Sec. Nbr; 111-11-1111
10) Enployee Type: PERU

12) Job Code: U102

14) Hourly Rate: 9 15.97

Next Action?

PgUp-Next Rec PgDn-Prev Rec F2-Change F3-Cont ESC-Oult

OKLAHOHA FORESTRY DIVISION
Species Update Option

■ Select Active Speclee

Species Nane

Species Code

Arborvitae
Austrian Pine
Autunn Olive
Bald Cypress
Black Locust
Black Walnut
Catalpa
EuonyMue
Green Ash
Hackberry

01
10
2S
IS
02

03
27
14
18

PRESS 'ESC TO GO TO HAIN HENU

Figure 7 -- A pop-up window which allows the
user to select a given species from the
list of active species.

Figure 8 -- A data entry used to enter personnel

information. Each field is validated for

type of data, length of the data field, and
the range of the data.

Not al I the information shown in figure 8
typed in by the user. The Oklahoma system is
designed to put information on the screen for the
user once it has enough data to perform this
operation. For instance, in figure 8 the user
would type in the employee type (PERM), area
•(C&W), and the job code (U102). The system
determines that this data corresponds to an Area
Forester of Grade 62. The user then entered the
step (7) and the computer responded with the
hourly rate ($15.97) .

Figure 8 also illustrates one of the primary
design features of the Oklahoma Nursery

Management System. At the bottom of the window
is a key selection menu. If the user were to
press the PgUp key, the system would bring the
next personnel record up on the screen. Pressing
PgDn would bring up the previous record. This
one key operation is designed throughout the
system and al lows the user to move through the
database and to select particular operations
without having to go another menu or another
screen.

In some cases, a large amount of numeric
data needs to entered into the database. The
Oklahoma system handles this by providing a
matrix-! ike screen system (fig. 9). The upper
part of the screen indicates the data record the
user is working with; the bottom part of the
screen is used for the data entry. Since not
every field will be used for storing data, the
user can move the cursor to the proper fields
(not unlike a popular spreadsheet package).

Naae; South, John R.
Address: 6909 Custer Road, «70a

Piano, TX 75023
Postlon: Area Forester

OKLAHOBA FORESTRY DIVISION
Add Hours By Category

8/11/87

SSN: 111-11-1111

Job Code: U102

Areai CtV

Type: PERM

Enter Tlae Spent On The Following Categories Fori 08/11/87

II Chealcals >

21 Hand Chea. >

3) Veedlng >

41 Fertilizer >

SI Soil Aaend. >

6) Irrigation >

7) Site Prep. >
81 Cover Crop >
91 Research >

Day's Coaaents:

101 Seed Inven. >

111 Equipaent >

121 Grounds >

131 Seed. Rec. >

141 Training >

151 Adain. >

161 Shipping >

171 Ship. Adan. >

181 Rech. Harv. >

191 Count/Tie >

201 Topcut >

211 Seed Harv. >

221 Seed Proc. >

231 Planting >

241 Cult. Pact.>

251 nisc. 1 >

261 Bisc. 2 >

271 Rise. 3 >

F2-Enter Coaaents F3-End
PRESS 'ESC' TO GO TO BAIN BEHU

Total Hours:

Figure 9 -- Numeric data is entered into the
database through a matrix-iike screen.

In the case of figure 9, the user is
entering the hours that a particular employee has
spent working on the listed cultural practices.
Since the hours spent on some cultural practices
(for instance, weeding) need to broken down to
the species which were worked, the Oklahoma
Nursery Management System alerts the user to this
fact by generating a pop-up window which allows
the user to enter the appropriate data (fig. 10).

COMMUNICATIONS BETWEEN COMPUTERS

Communications between computers is an area
which is beginning to receive a great deal of
coverage in the computer press. This media
coverage is doing more for the sales of expensive
communications hardware and software than it is
for generating legitimate development ideas in
operations converting from manual to automated
processes. There is no doubt that many
operations will eventually evolve into systems
which can effectively take advantage of concepts
such as local area networking, distributed

Naae: South, John R.
Address: 6909 Custer Road, #70S
-Hours By Species-

OKLAHOBA FORESTRY DIVISION
Add Hours By Category

SSNi

Job Code:

Please Breakdown 2. 00 Hours Over Species Vorked On

Arborvltae >
Cypress >
Black Locust>
Black Valnut>
Euonyaus >
Green Ash >
Hackberry >
Lacebark E1b>
Hulberry >
Osage Orange>
Pecan >
Red Ceder >
Russ. Olive >
Autusn 01ive>

Aust. Pine >
Aust. Pine C>
Pond. Pin* >
Scotch Pine >
Shtleaf Pine>
Vlrfl. Pine >
lap. Lob. Pine>
Cottonwood >
Baldcypress >
Bur Oak >
Catalpa >
B. Rose >
Redbud >
Sand Plus >

Total Hours:
2. 00

- 8/11/87

111-11-1111

U102

CIV

PERB

1 08/11/87

nt/Tl* >

cut >

d Harv. >

d Proc. >

nting >
t. Pact. >

c. I >

c. 2 >

c. 3 >

Total Hours:
6.00

Figure 10 -- A pop-up window which prompts the
user for the hours by species for a
particular cultural practice.

processing, and mainframe links. From what the
author has seen over the past few years, some
system designers get caught up in the technology
and overlook the true purpose of the system. In
fact, in some cases, they go so far as to
purchase the hardware and then try to make the
system fit the hardware.

WRONG!

The conceptual design of data acquisition
and database manipulation needs to be considered
first. Granted, the specifics of a particular
system may necessitate a hardware intensive
design, but that decision should not be made
until the database design is well thought out.

In the case of Oklahoma, the nursery system
is designed to be a stand-alone system. But it
is also designed in such a way that, should the
Forestry Division decide to expand into a
different configuration, the software can be
modified relatively easily to meet the changing
env i ronment .

The current system is designed to use
rudimentary data communications techniques as
illustrated in figure 11. The communication
techniques are rudimentary in that the data files
are transmitted from one node to the next
manually. For instance, the Area Forester can
transmit a set of data files to his Supervisor in
the capital. In another case, the author's firm
can transmit the latest version of a particular
report schema to both the capital's computer and
to the computer at the Forest Regeneration
Center. The point to be made is that this is all
the high tech communications the operation needs
at this point in time. Some day the nursery in
Norman may operate as a node in a distributed
processing environment with the capital, but that
day is still a ways off. The managers in that
operation have made the decision to concentrate
on their software environment and to develop the
overall system (hardware) as an incremental
pr ocess .

Oklahoma
Forestry
Division

Forest

Regenerat Ion
Center

Norman, OK

Information
Systems

Dallas TX

Figure 11 -- Communications between the computers
involved in the Oklahoma Nursery Management
System.

FINAL COMMENTS
Of the three levels of communications which

the system designers need to consider when
converting a manual operation to a computerized
environment, the most important area of
communications (from the standpoint of the
nursery) is the communication among the members
of the staff. This level of communications has
the most far-reaching impact and will have the
greatest long-range effect on the individuals in
the operation.

It is inherent that the system designers
stress simplicity when they develop a particular
automated environment. This will lead to less
resources being devoted to training and will
alleviate the frustrations that the
non-professional computer user feels when working
with a system that is not self-documenting.

Finally, it is important that the system
designers understand how hardware, software, and
the evolutionary stage of the development process
al 1 relate to each other. Though it would be
nice to incorporate all the neat, sophisticated
hardware available, in most cases, during the
manua 1 -to-computer conversion, these high tech
gadgets are inappropriate.

Applications of Portable Data Recorders
in Nursery Management and Research^

W. J. Rietveld and Russell A. Ryker^

Abstract. — A portable data recorder is a specialized
electronic device for recording and storing data in the
field, then transmitting the data directly to a computer,
eliminating the time and errors associated with manual data
transcription. Use of a data recorder allows error and com-
pleteness checking in the field, direct data collection from
instruments, and minimum turnaround time between data collec-
tion and completed data analysis. Considerations for select-
ing a data recorder to meet individual needs, and some draw-
backs, are discussed. Specific applications in nursery
management and research are presented.

INTRODUCTION

A portable data recorder (PDR) is a hand-
held, battery-powered, microprocessor-controlled
computer terminal (Cooney 1987). PDR's are
specialized electronic devices designed to collect
and store data in the field or laboratory (in
place of data forms) , then transmit the data
directly to a computer for processing. They
differ from laptop computers and hand-held calcu-
lators in that they are constructed for outdoor
use and their main purpose is to store data, not
process it. As microcomputer use increases in
forestry, more resource professionals are turning
to automated data processing to increase their
productivity. Although computer hardware and
software have advanced substantially in recent
years, data are still collected and entered into
computers by hand in many cases. These two steps
done manually can be expensive, time-consuming,
and full of errors. Alternatively, data can be
keyed into a PDR as they are collected, automati-
cally checked for errors and completeness, then
the completed data file can be transmitted dir-
ectly to a computer. Because manual data trans-
cription is eliminated, PDR's can significantly
reduce costs, number of errors, and turnaround

^Paper presented at the Intermountain Forest
Nursery Association Meeting, Oklahoma City,
Oklahoma, August 10-14, 1987.

2w. J. Rietveld is Research Plant Physiolo-
gist, North Central Forest Experiment Station,
Rhinelander, Wisconsin; Russell A. Ryker is
Research Silviculturalist (retired) , Inter-
mountain Forest and Range Experiment Station,
Boise, Idaho.

time. PDR's are becoming the technological link
between field measurements and data analysis.

Portable data recorders were first used in
supermarkets to expedite inventories. In recent
years they have found a new home in forest inven-
tory because of the volume and diversity of data
that are collected, the need for error checking
during data collection, cost savings in data
transcription, and reduced time to obtain results
(Anonymous 1987, Bergstrom 1987, Bottenfield and
Meldahl 1987, Fins and Rust 1987, Scott 1987).
Bluhm (1986) recently reported using a PDR in
nursery seedling inventory. Applications in
research have increased in recent years, not only
because more efficient data handling is needed,
but also because some PDR's can be interfaced to
digital and analog instruments to collect data
directly.

All these applications have certain charac-
teristics in common: (1) a large amount of data
needs to be collected and transferred to a compu-
ter for summary, (2) the costs of manual data
entry and verification need to be reduced, (3)
errors must be minimized, and (4) the time between
data collection and data processing should be
reduced. In this paper, we will discuss some
benefits and drawbacks of using PDR's, list some
considerations to help you decide which one to
purchase, and present some ways we use PDR's in
nursery management and research.

SELECTING A PORTABLE DATA RECORDER

Approximately two dozen devices on the market
could qualify as portable data collectors. Speci-
fications for most of the dedicated PDR's are
reviewed by Cooney (1985, 1987). They differ

widely in size, environmental durability, key-
board configuration, operating system, memory
capacity, programmability , and communications.
Most are powered by rechargeable batteries, have
some form of battery backup, and have some sort
of low battery warning, so there is a low risk of
losing data. The devices differ greatly in other
specifications; users need to determine what con-
figuration they need and select the appropriate
device. For example, in forest inventory error-
checking and completeness checking routines
should be built into the data collection scheme
so that complete and error-free data are obtained
while the survey crew is on site. For those appli-
cations, a PDR that supports BASIC, a powerful
and versatile programming language, is highly
recommended. Many other applications are more
straightforward, amounting to filling in the
blanks with data, so a simple edit mode may
suffice for entering data. Certain PDR's can be
interfaced with digital and analog instruments —
such as calipers , balance, area meter, porometer,
thermometer, and string potentiometer — so that
data can be transmitted directly to the data file
with the push of a button. In some cases the FDR
can be set up to take unattended readings from an
instrument at set times. Note, however, that
these applications require a custom program to
read the device and record the data. All PDR's
are equipped with a serial port for RS-232 communi-
cations via direct cabling or a modem to a host
computer .

Programmability is desirable for controlling
cursor movements, performing mathematical func-
tions, displaying menus and messages, checking
for errors, checking for completeness, and accept-
ing data from interfaced instruments. Most
devices provide some degree of programmability
using either a proprietary language that the user
must learn, or BASIC, a more universal language.
Although the proprietary languages can be used to
provide extensive error checking and to perform
mathematical functions, there are advantages to
purchasing a PDR that is programmable in BASIC
because the same language can be used for pro-
gramming on a microcomputer. However, a propri-
etary language may be more suitable for program-
ming the PDR to accept data from connected instru-
ments. While building in some programmed error
checking routines and minor manipulations of the
data may increase efficiency of data collection,
don't expect the PDR to perform the data summary
and analysis. For most applications, it is easier
to first transmit the data to a computer, then
perform the analyses using existing, more power-
ful application software. The examples in the
applications section will illustrate this point.

We recommend the following approach to
selecting a PDR: (1) list all applications
where a PDR may be useful, (2) evaluate that
list and retain only the applications where a
PDR is truly needed to increase efficiency (i.e.
large amounts of data, repetitive measurements,
need to transmit data to a computer, minimization
of errors, and cost savings from eliminating data
transcription), (3) make a list of capabilities

and features that the PDR must have to meet your
needs, (4) compare your list against the tables
of specifications provided by Cooney (1985, 1987),
and (5) evaluate product information and any
available published reports in making your
decision. Several companies and agencies have
conducted their own evaluations and may be
willing to share their information.

You may also wish to evaluate the economics
of using a PDR instead of conventional field
forms and manual data entry. You can do this by
following the procedure outlined by Fins and Rust
(1987). Assuming that data collection takes the
same amount of time by both methods, data trans-
mission and manual entry times can be estimated
closely enough to perform the comparative cost
estimates without actually using a PDR.

DRAWBACKS TO USING A PORTABLE DATA COLLECTOR

Some special problems, limitations, and
conflicts that may be encountered in using a
PDR are: (1) "computer phobia", (2) limited view
of the data file, (3) conflict with existing
data collection methods, and (4) cabling and
communications between connected devices.

Many people get "computer phobia" when
they are asked to record numbers electronically
rather than writing and storing them physically
on a tangible sheet of paper. The task of train-
ing personnel to use a PDR should be taken seri-
ously. It is a good idea to develop flow charts
and provide practice data for them to learn with
before important data are recorded. As a trans-
ition, it may be helpful to first write the data
on data forms, then enter the data into the PDR.

One limitation of most PDR's is the restric-
ted view of the data file, i.e. only a small
portion of the file is seen (and accessible) on
the display at one time. It is more difficult
for the user to compare current measurements with
previous measurements, which are more easily seen
on data forms. This is not a problem if you take
advantage of the PDR's power by writing a short
program to have the PDR display the previous
measurement (which must exist in the same file) ,
or you can have it compare the new measurement
with the previous measurement, beep if it is
smaller, and otherwise enter the data in the file.
A second problem related to the restricted view
is keeping track of your location in the file.
Because one row in the file is usually the data
for one tree, beginning users may skip a tree
and get out of sequence with the data file. There
are two ways to avoid this problem. One is to
print a copy of the data file with lines numbered
so users can keep track of their location by line
number, and the other is to program the PDR to
display the descriptors (e.g. block, treatment,
tree number) pertinent to each measurement being
entered .

Use of a PDR may not be compatible with
established plot measurement methods. For

example, some crews like to have one person
record data while two people measure trees in
adjacent rows. This does not work out very well
using a PDR because it cannot easily switch back
and forth in the data file. The same is true for
measuring adjacent rows in opposite directions,
unless either the plot or the data file is arran-
ged that way. When using a PDR, it is easiest
to enter data in the sequence they occur in the
data file. If more than one person is taking
measurements, they should leapfrog and provide
the data in the file sequence.

Cabling and communications between connected
devices are common obstacles when any peripheral
device is connected to a computer or PDR. Cabling
from a PDR to a microcomputer is usually not a
problem because the manufacturer often has a
serial cable available. Communications between
a PDR and a computer is best done with a communi-
cations program. Establishing communication is a
matter of setting up matching protocol (baud rate,
parity, duplex, data bits, stop bits, etc.)
between the two devices. The PDR manual will
usually give some helpful advice on this, but
there is no one solution because computers differ
widely. The same situation arises when a PDR
is cabled to an instrument to collect data. In
some cases, e.g. digital calipers, the device,
cable, and programming may be available from the
PDR manufacturer. In other cases, you purchase
the peripheral device with its optional serial
port, and the cabling and communications to the
PDR are up to you.

SPECIFIC APPLICATIONS OF PORTABLE DATA RECORDERS

In this section we will present two applica-
tions of the Polycorder^ (Omnidata International,
Logan, UT) in nursery management and research.
Published applications of other PDR's are:
Hewlett-Packard model 71 (Bluhm 1986); Husky
Hunter (Bergstrom 1987, Bottenfield and Meldahl
1987); Husky Special Performance (Scott 1987);
Oregon Digital Serial Plus II 7100 (Anonymous
1987); and Datamyte 1003 (Nieman et al. 1984).

Nursery Application

The USDA Forest Service Reforestation
Improvement Program (Rietveld et al. 1987)
involves repetitive measurement of several seed-
ling variables (seedling growth, morphology, root
growth potential, cold hardiness, stress test,
plant moisture stress, and field plot measurements)
at 11 nurseries. The same variables are repeat-
edly measured using the same sampling scheme, so
the basic data forms will be used over and over.
To facilitate data collection, summarization,
file organization, and archiving, a systematic

3The use of trade or firm names in this
publication is for reader information and does
not imply endorsement by the U.S. Department of
Agriculture of any product or service.

approach was developed that utilizes the Poly-
corder to record the data and transmit it to a
microcomputer. The following diagram shows how
the data will be processed:

DOWNLOAD

MODULE

FMT,

DAT

POLYCORDER

®
DATA

SUMMARY

ASCII FILE

LOTUS 123

GRAPHS
ARCHIVE

*. PRN

MACROS

The Polycorder requires a format file for
each data file that will be created. The format
file designs the data form. The data file is the
actual form, which is blank until data are entered.
Format and data files may be keyed into the Poly-
corder, loaded from a download module (1), or
downloaded from a computer. The next step is to
key the data into the data file (2). This can
be done in edit mode or in program mode, but the
latter requires writing a short Polycode program
to control cursor movements and must be matched
to the number of columns receiving data. Once
the data file is complete, the data are trans-
mitted to the computer (3) using direct cabling
between serial ports on each device. A communi-
cations program, Crosstalk, is used to capture
the data and create an ASCII file with a .PRN
extension. The ASCII data file is then imported
into a Preformatted Lotus 123 worksheet (4)
where the data are summarized, graphs are created,
and archiving is done (5) by running specialized
macros (preassembled lists of commands) on the
worksheet .

This scheme offers many conveniences as a
result of the repetitive nature of the applica-
tion: 1) because the same data files are used
over and over, they may be stored in a download
module (or the computer) and loaded into the
Polycorder whenever they are needed; 2) after the
data are offloaded to a computer, they may be
erased from the Polycorder file, retaining the
blank data file in the Polycorder for reuse; and
3) automated data processing is optimized, thus
the data can be transmitted to a computer and
summarized in minutes.

Research Application

The above approach works well for repeatedly
measured variables where the same data forms are
consistently used. However, that is often not
the case in research. Each study typically has
one or more unique data files; the data files
will usually be more complex, e.g. containing
several columns of descriptors for block, treat-
ments (in random order), and seedling number;

there may be a need to append additional columns
onto the original file for annual measurements;
and some data types may be transmitted to the PDR
via a serial port from a digital balance, calipers,
area meter, porometer, or other device. The follow-
ing diagram shows a typical data collection and pro-
cessing scheme in research applications of PDR's:

POLYCORDER

TRANSMIT (D

DATA
FILES

ANALYSIS

SPREADSHEET

STATISTICS

GRAPHICS

The format and empty data files are more
easily created on a computer, stored as ASCII
files, then downloaded directly to the Polycorder
(1). The format file can be written with EDLIN or
any word processor that will output an ASCII file.
The data file containing the descriptors (block,
treatment, tree number, etc.) in the desired
sequence can be "constructed" using Lotus 123, or
can be created directly with certain statistical
programs such as Mlnitab. The ASCII format and
data files are downloaded to the Polycorder using
a communications program. This step can be expe-
dited by using a communications program that has
versatile command and script file capabilities.
An example is presented in Table 1.

Data are entered into the PDR through the
keyboard (2) or by direct transmission from instru-
ments (2). Direct transmission of data from
instruments is very fast, but requires that a
Polycode program be written to accept, manipulate,
and file the transmitted data. For example, we
weigh dried plant samples without removing them
from the bags. Paper bags of the same size are
surprisingly consistent in weight. We dry a group
of empty bags along with our plant samples, deter-
mine an average empty bag weight, then enter that
value into a Polycode program. The program sub-
sets the measured weight from an alphanumeric
string transmitted by the balance, subtracts the
average empty bag weight, records the tissue dry
weight in the data file, performs cursor movements,
and provides file location prompts. This technique
works well for samples that have a dry weight
greater than 1 gram; the experimental error is
no greater than that introduced by removing the
plant samples from the bags to weigh them.

The completed data file is transmitted back
to the computer (3) , using a communications pro-
gram. File redirection programs such as Dpath
and File Facility are handy for organization pur-
poses because they allow you to store data files
in separate subdirectories on a hard disk, rather
than storing them all in the same subdirectory
with the communications program. The final step
of the scheme shows the data files being imported
into various spreadsheet, statistical, or graphics
programs for analysis (4) .

DISCUSSION

Portable data recorders have the potential
to increase efficiency of data collection in a
variety of applications. However, they are not
for everyone. Converting to a different method

Table 1. A Crosstalk script file (*.XTS) for transferring files
between a PDR and a microcomputer. The script file loads
automatically when it is given the same prefix as the command
file (*.XTK). The communication protocols used in the
command file must match those of the PDR.

GO LOCAL
CLEAR

ASK Type L for Load, T for Transmit, E for Edit, or Q for Quit
JUMP D0-@

LABEL DO-Q
QUIT

LABEL DO-L
SCREEN D
CLEAR

LWAIT CHAR " "

SEND

RWIND

LABEL DO-T
SCREEN D
CLEAR
CA

WHEN " " ALARM NOW
WAIT STRING " "
CA -
RWIND

LABEL DO-E
RUN

; insert mating call character sent by PDR, if used

; insert end of file character sent by PDR
; insert end of file character sent by PDR

requires an investment in new equipment, and time
to evaluate the actual need for the device, to
learn how to use it, to develop a system to apply
it, and to train personnel to use it properly.
Thus, there will be a start-up period before a
net increase in efficiency is realized. You
should be reasonably certa in that using a PDR
is justified before you make a commitment. Use
of a PDR (and a computer for that matter) may
well help you reach a higher level of technology,
efficiency, and productivity. However, that is
only achieved through learning, commitment, and
adaptability.

In research applications, we find that using
PDR's allows us to take more data than would
otherwise be possible with available personpower.
This is especially true when instruments are inter-
faced with a PDR. One person can take several
times more data in a single day, with good pre-
cision and less fatigue. Most technicians are
enthusiastic about using data collectors because
they save time, and the person feels a sense of
accomplishment for mastering the use of a sophis-
ticated electronic tool. Because data entry and
verification are eliminated, the technicians are
relieved of those tasks, and the computer is
freed for other uses.

In summary, PDR's are a cost-effective
alternative to conventional data sheets for data
collection and manual entry of data into a
computer. Data collection time is about the
same with a PDR, but the need for manually enter-
ing data into a computer and verifying them is
eliminated. Other benefits are the opportunity
to perform error checking in the field, interface
with instruments, and obtain faster turnaround
of completed data analyses. In general, if a PDR
is used frequently, the labor savings will pay for
the device in 1-2 years.

LITERATURE CITED

Anonymous. 1987. Portables increase productivity
for Anderson-Tully. The Compiler 5(l):25-26.

Bergstrom, Dorothy. 1987. Hand-held data

recorder changes inventory system. Pages
16-19 In Forestry Research West. August
1987. USDA Forest Service, 240 West
Prospect Street, Fort Collins, CO.

Bluhm, Douglas A. 1986. Using the HP71 hand-
held computer for seedling inventory.
Pages 73-74 In Thomas D. Landis (ed.).
Proceedings: Combined Western Forest
Nursery Council and Intermountain Nursery
Association Meeting [Tumwater, WA, August
12-15, 1986] USDA Forest Service General
Technical Report RM-137, Rocky Mountain
Forest and Range Experiment Station, Fort
Collins, CO.

Bottenfield, Timothy R. and Ralph S. Meldahl.
1987. Auburn researchers 'harvest' data
with Husky Hunter. The Compiler 5(1):
23-24.

Cooney, Timothy M. 1985. Portable data
collectors, and how they're becoming
useful. J. For 83:18-23.

Cooney, T. 1987. Update on portable data
recorders. The Compiler 5(1): 15-22.

Fins, Lauren and Marc Rust. 1987. Comparative
costs of using an electronic data recorder
and field forms. Western J. Appl. For.
2:28-30.

Nieman, T. , W. Kean and W. Cheliak. 1984.
An electronic "notebook" for forestry
application. Information Report Pl-X-38,
Petawawa Nat. Inst., Environment Canada,
Chalk River, Ontario KG J IJO, 44 p.

Scott, Charles T. 1987. The northeastern
forest survey data recorder system.
Paper presented at FORS 4th Annual
Meeting [Syracuse, NY, May 13-15, 1987].
Forest Resources Systems Institute,
Florence, AL. (unpublished)

Superabsorbent Hydrogels and Their Benefits
in Forestry Applications^

Fernando Erazo^

Abstract . --Superabsorbent hydrogels applications
for forestry use have been developed over the last
few years and are now being uaed as soil additives
in growing containerized seedlings and as "ROOT-DIP"
prior to packaging and storage.

INTRODUCTION

AGLUKON AGRI -PRODUCTS is part of the
worldwide group of Schering Agrochemical
Companies .

In Europe, it is estimated that 60%
of pine trees are affected by acid rain.
Schering (AGLUKON S.D.) is the founding
researcher company that in 1984 started
and successfully developed products to
prevent damage of acid rain in young and
established pines.

In the U.S., Schering (AGLUKON) has
been marketing agricultural superabsorbents
since 1979. In 1982, we built the first
U.S. synthetic hydrogel facility for agri-
cultural applications. AGLUKON is the
manufacturer of ROOT-DIP superabsorbents.

In 1987, AGLUKON will introduce, for
trials, a specialty foliar potassium
compound for hardening of seedlings. This
could allow nurserymen to lift seedlings
even if weather remains warm.

1. WHAT ARE SUPERABSORBENTS?

Crosslinked polymers that absorb and
retain fluids hundreds of times their own
weight, are call superabsorbents.

Paper presented at the Intermountain
Forest Nursery Association, hosted by the
Oklahoma State Dept. of Agriculture Forestry
Division, Oklahoma City, Okla. August
10-14, 1987.

Fernando Erazo is President of
Aglukon Agri-Products, Congers, N.Y.

The ability to absorb and retain water
and other fluids, has encouraged many a
company to seek a variety of applications:

Health Care--Diapers , sanitary napkins

Industrial Use--Municipal water treat-
ment, wipers, oil mudding

Agriculture--?

2. ADVENT OF SUPERABSORBENTS IN AGRICULTURE

It is difficult to believe that we are
in the third decade of some form of super-
absorbent usage. (See Table 1.)

3. TYPES OF SUPERABSORBENTS

The 1960 's

In the early sixties, the Agricultural
Research Group of Union Carbide already had
developed a hydrogel that absorbed up to 40
times its own weight in water... this was a
polyethylene polymer combined with sawdust . . .
a soft gel designed to be mixed with soil,
to improve water capacity and aeration of
soil mixes. This was the first gel developed
specifically for horticultural practices.

The USDA in Illinois then discovered
that crosslinked acrylonitrile with corn
starch could also absorb over 100 times its
own weight in water. The USDA licensed
several companies to produce such a super-
absorbent gel. Most of these designed uses
for health care, and some agricultural
segments .

Several companies also produced
cellulose gels, and research for synthetic
hydrogels had begun.

TABLE 1. — TYPES OF SUPERABSORBENTS

Chemical Name

or Ingredient

Market Application

Period

Polyethylene Oxide/ sawdust

soil amendment

1965-1978

Polyvinyl Alcohol

diapers

1975-present

Aery lonitrile/ starch

tampons, napkins

1979-present

soil amendment

1966-1983

planting seedlings

1978-present

Potassium Propenoate/Propenamide

soil amendment

1978-present

copolymer

gel seeding

(Potassium Polyacrylamide/Poly

plug-mix planting

1982-present

Acrylate Copolymer)

root-dip

Acrylic Acid (polyacrylates)

diapers

1981-present

sanitary napkins

1982-present

water treatment

1983-present

soil amendment

1984-present

Acrylamide (polyacrylamide)

diapers

1983-present

sanitary napkins

1984-present

soil amendment

1983-present

Acrylic Acid/Acrylamide

diapers

1985-present

(combinations)

soil amendment

1985-present

the 1970 's

The early products that combined a
synthetic polymer with natural polymers
penetrated on a small scale, several areas
of horticulture and many trials were con-
ducted in agricultural applications,
including planting of bare-root seedlings.

In the late seventies, however,
researchers in the U.S., Japan and England
announced the discovery of different types
of synthetic superabsorbents , which sought
to eliminate the problems associated with
natural polymers.

Most of these newly discovered super-
absorbents found a home in the diaper
industry, and only one in the U.S. built
a facility and began application and product
development solely for agricultural uses.

the 1980 's

Several of the manufacturers of super-
absorbents for diapers and municipal water
treatments are now seeking to expand their
market into all segments of agriculture.

Many of these products are not fit for
our industry. Therefore, it is our respon-
sibility to know why.

It is also our responsibility to
recognize which of the superabsorbents are
good for agricultural applications.

Proven technology has now been developed
and is in place for specific segments of
agriculture, horticulture, foresty. This
technology application is based on the choice
of a correct product for a specific
application .

4. APPLICATIONS PRACTICED IN
HORTICULTURE AND AGRICULTURE

Propenoate propenamide copolymers are
successfully used as follows:

Soil Additive

-to increase water holding capacity

-to improve aeration and drainage of soil mix

-reduce irrigation frequency

-increase shelf life

-maintain moisture equilibrium

The superabsorbent must be able to
release wate. when the moisture equilibrium
of the soil -"hanges, or as the roots need it.

Major uses are in container growing and
tree and shrub planting.

Growing Of Transplant Plugs
In The Greenhouse

The advantage is that the "chunks" of
gel are carried from the greenhouse to the
field in each plug, thus...

-not only has the grower received the benefit

while growing the plug, but
-he can also eliminate transplant shock

during transplanting operations

Fluid Drilling Or Gel Seeding Of
Pregerminated Seeds

In this case, the superabsorbent gel
must make a perfect suspension , soft, but
consistent , to protect the delicate 2 mm
seedlings while they are extruded to the
soil .

Root Dipping Applications

It is now well proven that a major
factor in field survival of bare-root
seedlings is the proper treatment and
handling of seedling roots prior to plant-
ing them. Root dipping with the correct
gel will fulfill that need.

5. USE OF THE CORRECT SUPERABSORBENT
IN FORESTRY APPLICATIONS

Soil additive for growing containerized
seedlings .

Root dip spray for bare root seedlings,
after lifting, prior to storage.

6. SOIL ADDITIVE FOR GROWING
CONTAINERIZED SEEDLINGS

System

The small granules of superabsorbents
are thoroughly blended into the peat mix
prior to filling the plugs.

"Viterra" absorbs free water that is
normally lost to leaching. As the "Viterra"
granules expand, the soil volume increases
and aeration and drainage improves. Each
granule acts as a tiny water reservoir,
replenishing moisture as the soil dries out,
or absorbing excess moisture. Essentially,
"Viterra" acts as a buffer in your soil,
stabilizing the moisture levels for optimum
root development.

Benefits

The small amount of superabsorbent will
create optimum growing medium with consistent
moisture equilibrium, resulting in a homo-
geneous size seedling which can reduce
grading activity with less frequent
irrigations .

An additional benefit is that the
containerized seedlings already have
hydrated gel "chunks" to protect against
transplant shock, and give the forester
a better stand.

Rates

Mix 1.5 lbs. of superabsorbent for each
cubic yard of mix OR 1 oz. per cubic foot
of mix.

7. ROOT DIP SUPERABSORBENT FOR
BARE ROOT SEEDLINGS

A nursery can now choose the easiest,
least messy, labor prompt and most effective
method from the following:

a. root packing with peat moss

b. dipping in a clay slurry

c. spraying with ROOT-DIP
superabsorbent

If we are concerned with field survival
of bare-root seedlings, we must give their
roots the best care and treatment available.
ROOT-DIP will keep the roots in a moist
condition, and will prevent root "dry-out"
during storage and shipping.

How to use ROOT-DIP

Easy to use. There is no need for
special equipment to produce a ROOT-DIP
slurry suspension. Just add the correct
rate of ROOT-DIP to water. Wait a few
minutes to hydrate, and your ROOT-DIP treat-
ment is ready!

Spray the bare-root seedlings with
ROOT-DIP slurry.

The tiny water-laden gel particles will
cling to the seedling roots, and will
replenish moisture to the roots during
storage and shippings.

Rates

One pound of ROOT-DIP for 33 gallons
of water is sufficient to treat up to
15,000 bare-root seedlings, at an average
cost of $.367/1,000 seedlings, or less.

8. BUT...

Let's remember that not all super-
absorbents are the same. (See Table 2.)

In fact, ROOT-DIP superabsorbent is
good for treatment of bare-root seedlings,
but not good for treatment of baby diapers.

9. WHAT TO LOOK FOR IN A ROOT-DIP GEL

-Non-toxic by FHSA standards
-Non phytotoxic, must be inert
-Neutral Ph

Table 2. — Comparison of "VITERRA" ROOT-DIP versus other super- absorbents .

SYNTHETIC SUPERABSORBENT MEASUREMENT TEST

Suspension
Gel Strength
Water Absorption

Good
Soft
Good

National Tree Seed Laboratory
September 9, 1986

SCREENING FOR PARTICLE SIZE ROOT-DIP

COMPETITOR

o dllip J. c:

gr .

Over #20 screen

. 19

gr. .3%

8 .27

gr . 16

Through #20 screen and over

#40 screen

gr. 98%

35.75

gr. 71

Through #40 screen (Dust)

.79

gr. 1.6%

5.89

gr. 11

,02

gr.

n Q
. u y

gr .

ABSORPTION

Superabsorbent Sample

.25

gr.

.25

gr.

Water sample

300

ml.

300

Hydrated Gel Particles

86 . 67

gr.

49.87

gr .

Excess Water Vacuumed off

205

243

Excess Water Lost in Filter

8.58

7 .38

Absorption Rate

346:

198

: 1

CHARACTERISTICS

Particle Size

Excellent

Poor

Poor
Hard
Poor

Dustless — Superabsorbent dust added to water
can become a "coating." If this coating
dries out, it can act as a barrier, sealing
off oxygen to the roots.

Uniform particle size--In order to obtain
(-20+35) a uniform, stable suspension, with
sufficient hydrated granules, to adhere to
the seedlings ... when the granules are too
large, they will fall off roots.

-Propenoate-propenamide copolymers with the
correct rate of potassium polyacrylate and
polyacrylamide .

-Absorption capacity should be no more than
400 times its own weight, and no less than
300 times.

-The absorption capacity and size of the
granule determine the weight of the
hydrated gel that clings to the roots.

-ROOT-DIP superabsorbent should be coated
with hydrophobic adjuvant to avoid lumping
during hydration.

-Should be easy to use.

-The physical-chemical properties of the
ROOT-DIP gel should ensure that moisture
is released from the gel to the roots when
the moisture equilibrium of the roots need
it. (diaper gels hold and retain water.

but do not release it)

-When dry, the ROOT-DIP gel looks like a
white crystal. It is odorless, free
flowing .

-When hydrated, the ROOT-DIP gel should not
be rubbery or hard. To be sure that
moisture can be released, gel should be on
the soft side.

-Hard gels will fall off the seedlings
during handling.

-The ROOT-DIP gel must be supported by

good quality control and a company that

is in the agricultural business, knowledgable

and responsive to grower needs.

10.

THE FUTURE

The future of superabsorbents in
forestry is bright.

The aim will continue to be to encourage
governments , industry , and the public in
general, to forest the land, to preserve it
and enjoy it, and in so doing, to utilize
safe proven products at an economical cost.

Our responsibility as nursery-
men, is to be there and to utilize
the best methods available to grow
the best seedlings.

Organic Matter: Short-Term Benefits
and Long-Term Opportunities^

John G. Mexal and James T. Fisher^

Abstract: Crop benefits derived from organic
amendments to southern nurseries appear minor and
limited by the rapid rates of OM decomposition common
tO/ the region. This paper reviews a case study and
related studies to examine the actual and potential
benefits of amendments as determined by the kinds,
amounts and frequencies of applications. It is
possible to increase the stable fraction of OM in
nursery soils and, potentially, to improve seedling
growth and yield. However, it will be necessary to
apply amendments more frequently than conventionally
done .

INTRODUCTION

Nursery managers believe organic
amendments are essential to efficient
nursery production in southern regions.
This belief is at least partially
derived from the manner in which
seedlings are harvested. In contrast to
most agricultural crops, nursery
seedlings are harvested as whole plants,
and only negligible amounts of
post-harvest crop residues remain in the
soil.

New Mexico State University
Agricultural Experiment Station Paper
No. 290., presented at the 1987
Inter-Mountain Nursery Conference,
Oklahoma City, OK, August 10-14,
1987 .

Authors are, respectively.
Assoc. Professor and Professor, Dept.
of Agronomy and Horticulture, New Mexico
State University, Las Cruces, N.M. 88003

The authors gratefully acknowledge
funding provided by the USFS and
DOE (Contract # AC 0 4 -7 6ET- 3 3 6 2 6 ) .

Clearly, organic matter (OM) is
essential for efficient crop production.
It acts as a reservoir of nutrients that
become available slowly as decomposition
proceeds. In addition, OM improves soil
cation exchange capacity (CEC).
Consequently, more nutrients are
retained against leaching in soils high
in OM. OM also buffers the soil against
abrupt changes in soil acidity that can
occur when fertilizers such as ammonium
sulfate are applied.

OM improves water infiltration and
augments net soil moisture retention.
These benefits are important for soils
that tend to crust or that have high
salt content, esp., sodium (DeBano,
1981). OM adsorbs the cations and
prevents flocculation of clay particles.
Certain types of OM can suppress
soil-borne plant pathogens such a
Py thlum and Phy topthora through the
release of fungicides. OM also can
alleviate the symptoms of certain
abiotic diseases caused by herbicides or
excess salts.

Nurseries apply a variety of
organic amendments to maintain soil OM
(Davey, 1984). In the South, conifer
sawdust and bark are commonly applied
because of the abundance of wood mill
residue. Other OM amendments include

hardwood sawdust and bark, municipal
waste and animal waste. Use of these
materials is usually limited by local
availability. For example, fish waste
or horse manure is applied if the
nursery is near a hatchery or racetrack,
respectively. Transportation costs
generally preclude nurseries from using
northern peat moss.

Green manures or cove
add to the stable organic
the soil. In fact, when a
turned under, soil OM may
decrease after a brief per
and McKee, 1938). Essenti
stimulation of microbial a
created by the addition of
decomposable food supply c
reduction in the steady st
soil OM. However, cover c
without merit; they can be
effectively to reduce wind
to eliminate plow pans.

r crops do not
fraction of

cover crop is
actually
iod (Pieters
ally, the
c t i V i ty

a readily
an cause a ne t
ate level of
rops are not

used

erosion and

Nursery soil OM depends on location
and soil type. Nurseries in the
Northwest tend to have OM levels greater
than 3 % (Davey, 1984). However,
nurseries in the South average less than
3 % soil OM ( South and Davey, 1982)
and those on sandy or sandy loam soils
have less than 1.5 % OM. Nurseries in
the Southwest ( New Mexico and Oklahoma)
average about 1 % (Hyatt, 1980; Windle,
1980) .

The objective of this paper is to
discuss the short-term response of
nursery soil to organic matter additions
using the USFS Albuquerque Tree Nursery
as a case study, and to discuss the
long-term opportunities to improve crop
production through better OM management
in nurseries.

followed over the course of the
production cycle (1.5 growing seasons),
and seedling yield and morphology were
determined November 1985.

Results

The OM additions caused immediate
but short-term changes in soil OM and
nutrient availability. Soil OM
(particles < 2 mm) was affected most by
sawdust (Fig. 1). The sawdust plots had
an OM content of nearly 4 % about 2
months after application. Sludge
increased OM less than 1.0 %. Particles
> 2 mm were still visible in the soil,
but these are not measured in standard
OM determinations. In all likelihood,
particles this large neither stimulate
soil microbial activity nor directly
influence seedling nutrition.

Organic Matter (X)
5

9 IB 11 12
1984

4 5
1985

Figure 1. — Effect of organic amendments
on soil test OM at the Albuquerque
Tree Nursery. Only the peat moss
treatment is significantly
different from the control (CX =
.05) for the July 1984 sample only,
Vertical bars represent + 1 S.E.
of the mean.

ORGANIC AMENDMENTS APPLIED TO A
SOUTHWESTERN NURSERY: A CASE STUDY

Treatments

Before fumigation for the 1984
crop, approximately 12 mm of OM was
incorporated into the surface 15 cm.
The OM treatments included
gamma-irradiated sewage sludge, pine
bark, pine sawdust, horticulture grade
peat moss and no OM. Treatments were
added at the rate of 67 t/ha, except
sawdust that was added at 43 t/ha. Soil
and seedling nutrient status were

The response of soil nutrients to
OM was also short-lived. Only sludge
increased soil NO (Fig. 2A). Bark and
peat moss had no detectable effect, but
sawdust caused rapid immobilization of
NO^. By August, NO^ in the sawdust
plots was 1 ppm con-^'ared to 28 ppm for
the control. By December, all plots had
only 1 ppm NO^. Five applications of
urea (53 kg/ha) failed to increase soil
NO to more than 20 ppm, and by August
1985, soil NO^ returned to 1 ppm, the
p r e -a pp 1 i c a t io n level.

Other nutrients
behaved similarly (Fi
Generally, soil nutrl
increased shortly aft
and decreased over th
rotation. For exampl
145 ppm before sowing
months later. Again,
soil K slightly early
while sawdust decreas
Bark, and peat moss di
nutrient levels. All
differences disappear
1 984 .

( P , K and Fe )

g. 2B-D).

ent levels

er OM application,

e remainder of the

e, K decreased from
to about 60 ppm 14
sludge increased
in the season,

ed soil K slightly.

d not alter
t reatment

ed by Decembe r

OM amendments had no effect on
seedling yield, height, caliper or fresh
weight. However, seedling R/S was
significantly reduced by bark., sludge
and peat moss (Table 1). Seedling shoot
fresh weight was positively correlated
with increased soil nutrient levels
brought about by the OM additions.
However, R/S and shoot fresh weight were
only sightly affected by OM addition.
Nevertheless, the responses detected do
indicate that OM amendments can alter
seedling morphological development.
However, additional work, is needed to
adequately explain this relationship.

Figure 2. — Effect of organic amendments on soil test nutrient
contents at the Albuquerque Tree Nursery, where A =
nitrogen, B = phosphorus, C = potassium and D = iron.
Arrows in Fig. 2A indicate applications of 53 kg/ha of urea.
Vertical bars represent _+ 1 S.E. of the mean; N.S. = not
significant.

Table 1. --Effect of different organic
amendments on 1.5 + 0 ponderosa
pine seedling morphology.

Height

Caliper

Fresh

Weight (g)

Treatment

(cm)

(mm)

Shoot

Root

R/S

CONTROL

10.5

3.4

3.84

1.94

.56

SAWDUST

9.7

3.4

3.59

1.74

.54

BARK

11.4

3.4

3.98

1.86

.51 '

PEAT MOSS

10.4

3.2

3.66

1.72

.51 '

SLUDGE

11.2

3.S

4.16

1.89

.50 '

MS.

N.S*

MS.

Organic Matter (%)

0 3 6 9 12 15 IS 21 24 27 30 33 36

Time after Application (mo)

i Significontly different from Control (d-.OS)
■* Corrdottd with Nov. 1989 Soil CPl and CN]

DISCUSSION

Although not encouraging, our
results generally agree with studies
conducted in the southern United States.
Saloman (1953) treated soil with various
levels of sawdust and found no change in
soil OM and no improvement in plant
growth. Similarly, the addition of
sewage sludge to a nursery soil in the
Northwest resulted in few improvements
among the conifer species tested, and
results from the outplanting trials were
generally negative (Coleman, et al.,
1986). However, Berry (1980) found

that pine responded po

s i

1 y to the

addition of sludge in

0 r

ida nursery.

Seedlings responded be

s t

s ludge

applied at rates of 60

-I

/ha. The 67

t/ha treatments employ

our study

failed to promote a si

response in

ponderosa pine seedlin

0 w

th.

Long-Terra Oppor

n i

t i

e s

Many studies, inc

this one,

examine the short-term

e s

n s e of

soils, and generally r

0 r

the response

of one seedling crop t

s i

ngle OM

addition. Such studie

i n

t to the

rather abrupt changes

0 c

r r

i ng in

amended soils. Within

e a

r , mo re than

60 % of the OM added will decompose, and
about 90 Z will be decomposed in 2 years
or less (Davey, 1984). Davey and Krause
(1980) believed the stable fraction of
soil OM could be increased about 0.1 %
by adding 20 t/ha. However, Manson
(1983) found peat moss decomposed more
readily as application rates were
increased. Munson found OM levels in
the soil would return to ambient levels
in 28 months after the addition of 22
t/ha, and 34 months after the
application of 90 t/ha (Fig. 3).

Figure 3. --Effect of rate of application
on the decomposition of sawdust in
a Florida nursery (after Munson,
1983). Return to ambient level is
extrapolated to be 28 mo for 22
t/ha, 34 mo for 45 t/ha and 35 mo
for 90 t/ha.

Apparently, amendments would have to be

applied more frequently than once every

3-4 years to cause a net increase in
stable soil OM.

A similar conclusion can be drawn
from May and Gilmore (1984) who applied
OM repeatedly in a loblolly pine nursery
during a 6-year period. Sawdust was
applied at 33 or 66 t/ha rates repeated
two, three or six times over the the
course of the study. The maximum rate
(66 t/ha applied every year) added a
total of 396 t/ha of organic matter and
effectively increased soil OM from 1.9 %
to 3.2 % (Fig. 4). The OM level of the
control plots was not altered over the
6-year period, despite the harvest of
six seedling crops. Soil OM responded
in a linear manner to the amount applied
and to the frequency of application.
The positive effects reported by May and
Gilmore contrast sharply with studies
employing single applications of
comparatively large amounts of organic
matter, and consequently reporting no
practical benefits (e.g., Munson, 1982).

A relationship often ignored in the
United States is the efficacy of
inorganic fertilization as a substitute
for organic amendments. Most
information on this subject comes from
the United Kingdom where the climate is
much less severe than in the South or
Southwest. Nevertheless, trials
conducted in the United Kingdom have
shown that inorganic fertilization can
serve as a suitable replacement for OM.

However, in certain tests, the best
treatment was a combination of inorganic
fertilization and OM addition.

Organic Matter {%)

3.5

3.0

2 5

2 0

, RATE (t/a)

30/6

• 30/2

0 M. • 1.84 XO 0076(lont)
I • 99(X'0OI)

30
L_

120

150

leot/a

66 132 198 264 330 396
Sawdust Applied {t/ha)

Figure 4. — Effect of amount and

frequency of application of sawdust
on OM content in a Alabama nursery
soil (after May and Gilmore, 1984).
The application rate was 16 and 33
t/ha applied either 2, 3, or 6
times in 6 years.

Future Prospects

Orgonic Matter (%)
4 ,

<14 l/ho/4yr(SPLIT

12 3 4 5 6 7

Yeor

I Cover Crop | 1-0 2-0 | Cover Crop | 1-0

Figure 5 . --Hy p o t he t i c a 1 trends in soil
OM following different schemes of
addition (adapted from Davey and
Krause, 1980)

from frequent
with comparati
infiltration r
OM level signi
permeability,
occurrence of
need to contro
related conce r
increase soil
reduce the occ
associated wit
numerous studi
shown .

applications are those
ve ly low water
ates. As seen in Fig. 6,
ficantly affects water
In the Southwest, the
torrential rains and the
1 evaporative losses are
ns. OM should also
nutrient retention and
urrence of crop maladies
h salts and pesticides, as
es of low-OM soils have

Few studies have actually
demonstrated that OM additions applied
at conventional frequencies
significantly improve nursery soils,
seedling crops or profit margins.
Present day practices will not
significantly increase soil OM levels,
and crop benefits will be of minor
importance (see Fig. 4). More
specifically, many nurseries apply 22
t/ha every 3 or 4 years before sowing
2+1 or 2+2 crops, respectively.
Clearly, such practices will not
significantly improve crop yield (Fig.
5). Within 4 years, the additional OM
will decompose and will not cause a net
gain in steady-state soil OM.
Therefore, to significantly increase the
stable OM fraction, at least 22 t/ha
should be applied years 1 and 2 before
sowing a cover crop.

Permeability (ml/IOmin)
%

200

1276)

(459)

O = BARK
■ = PEAT MOSS
• = SAWDUST

100.

0 ^5 5.0 7.5

Organic Matter Applied (cm)

Frequent applications of organic

amendments will benefit some nurseries Figure 6. — Effect of type and amount of
more than others. Among the problem OM on water permeability (after

soils potentially benefitting greatly Pokorny, 1982).

CONCLUSIONS

Extrapolations from our work, and
the study of May and Gllmore (1984)
suggest that nursery soil OM can be
raised to higher stable levels, even in
regions where high temperatures and
irrigation are conducive to rapid OM
decomposition (Munson, 1982). Also
evident is that present day amendment
practices would have to be revised to
provide the benefits desired.

Although OM amendments
theoretically can improve nursery yield,
field data for this region are
inadequate to confidently predict
economic benefits. For the present, we
recommend nurserymen in the South and
Southwest either apply no OM, or at
least 2 applications of 22 t/ha over a
4-year rotation. Additionally, nursery
managers should not overlook the
opportunity to add OM before sowing the
seedling crop, or the benefits derived
from mulching with organic materials
such as bark.

LITERATURE CITED

Berry, C.R. 1980. Sewage sludge

effects soil properties and growth
of slash pine seedlings in a
Florida nursery, p. 46-51. Iji
Proc. 1980 Southern Nursery Conf . ,
Sept. 2-4, 1980, Lake Barkley, Ky.
USES Tech. Pub. SA-TP17

Coleman, M. , J. Dunlap, D. Dutton and C.
Bledsoe. 1986. Nursery and field
evaluation of compost-grown
coniferous seedlings, p. 24-28. In
Proc. Combined West. Forest Nursery
Coun. and Interraount. Nursery
Assoc. Mtg., Tumwater, Wa.

Davey, C.B. 1984. Nursery soil organic
matter: management and importance,
p. 81-86. I_n M.L. Duryea and T.D.
Landis (eds.) Forest Nursery
Manual, Martinus Nijhoff/Dr W. Junk
Publ . , Bos ton .

Davey, C.B. and H.H. Krause. 1980.
Functions and maintenance of

organic matter in forest nursery
soils, p. 130-165. In Proc. N.
Amer. Forest Tree Nursery Soils
Wkshp. July 28-Aug. 1,, 1980.
Syracuse , NY .

DeBano, L.F. 1981. Water repellent
soils: a state of the art. USES
Gen. Tech. Rep. PSW-46, 21 p.

May, J.T. and Gilmore, A.R. 1985.

Continuous cropping at the Stauffer
nursery in Alabama, p. 213-221. In
D.B. South (ed.) Proc. Internat.
Symp. on Nursery Mgmt. Practices
for Southern Pines, Montgomery, Al.

Munson, K.R. 1983. Decomposition and
effect on pH of various organic
soil amendments, p. 121-130. In
Proc. 1982 Southern Nursery Conf.,
July 12-15 & Aug. 9-12, 1982,
Oklahoma City, Ok and Savannah, Ga.
USPS Tech. Pub. R8-TP4.

Myatt, A.K. 1980. Soil pH and salinity
problems at Oklahoma State nursery,
p. 96-97. rn Proc. North Amer.
Forest Tree Nursery Soils Wkshp.,
July 28 - Aug. 1, 1980, Syracuse,
NY .

Pieters, A.J. and R. McKee. 1938. The
use of cover and green-manure
crops, p. 431-444. Tn Soils and
Man, The Yearbook of Agriculture.
USDA, Washington, D.C.

Pokorny, F.A. 1982. Pine bark as a
soil amendment, p. 131-139. rn
Proc. 1982 Southern Nursery Conf.,
July 12-15 & Aug. 9-12, 1982,
Oklahoma City, Ok and Savannah, Ga.
USFS Tech. Pub. R8-TP4.

Salomon, M. 1953. The accumulation of
soil organic matter from wood
chips. Soil Sci. Soc. Amer. Proc.
18 : 114-118.

South, D.B. and C.B. Davey. 1982. The
southern forest nursery soil
testing program, p. 140-170. In
Proc. 1982 Southern Nursery Conf.,
July 12-15 & Aug. 9-12, 1982,
Oklahoma City, Ok and Savannah, Ga.
USFS Tech. Pub. R8-TP4.

Windle, L.C. 1980. Soil pH and
salinity problems at the
Albuquerque Forest Nursery, p.
87-88 . I_n Proc. North Amer. Forest
Tree Nursery Soils Wkshp., July
28-Aug. 1, 1980, Syracuse, NY.

-1

The Trees Unlimited Program: An Experiment
in Establishing Seedling Plantings^

Robert C. Oswald^

Abstract .--Trees Unlimited is a pilot project formed in
1985 to provide an integrated, year-round program of planting
design, seedling planting, and maintenance to rural land-
owners in northern Colorado. It is a nonprofit program which
sells seedling survival products and total tree care services
associated with the establishment of conservation plantings.

INTRODUCTION

Trees Unlimited was formed in 1985 through
funding by an association of four soil conserva-
tion districts in the northern front range area of
Colorado and the State Soil Conservation Board.
The intent was to provide not only promotion and
sales of seedling trees in the area but also to
provide to the rural landowner a source of plan-
ning and design assistance, site preparation,
planting, and other tree care services associated
with the establishment of seedling conservation
plantings.

The program operation is similar to that of a
small business. Although it is nonprofit, it must
generate its own operating budget. Therefore,
there is a fee charged for services besides the
price of goods and materials sold.

ORGANIZATION

Trees Unlimited is overseen by a board con-
sisting of a member from each of the four soil
conservation districts involved. There is a
program manager who reports the progress periodi-
cally to the board but operates the program mostly
autonomously.

Cooperating with the program are the local
field offices of the Colorado State Forest Service
(CSFS) and the USDA Soil Conservation Service
(SCS). These offices actively refer interested
parties to Trees Unlimited. These same district
offices also help support the program through
lending field assistance, office and storage
space, and seedling storage facilities during the
spri ng.

Paper presented at the Intermountain Nursery
Association Meeting, Oklahoma City, Oklahoma,
Augus| 10-14, 1987.

Robert C. Oswald is the Tree Program Manager
of Trees Unlimited, Longmont, Colorado.

The original targeted market for sales of
seedling conservation plantings was the large
number of agricultural producers in the area.
However, due to various factors, the majority of
plantings sold during the last two years has been
to owners of small rural acreages. Because the
area is situated near several population centers,
there is an abundance of the "hobby farms" in the
1,500 square miles that Trees Unlimited serves.

PLANTING SERVICES

Trees Unlimited tries to make available a
wide variety of products and services for its
customers. Various combinations of materials and
services are needed in each different situation,
and assistance is given to the landowner to decide
which practices and plants are appropriate or
needed. In these seedling plantings, the plant
material is typically a small percentage component
of the total program cost. Overall, labor costs
are the largest portion, followed usually by cost
of drip irrigation materials. Some representative
prices of services are shown in table 1.

The program manager will perform an initial
site visit and landowner consultation, design a
planting and/or irrigation plan, offer several
site preparation and weed control methods, and
detail all of these prices in an itemized bid.
Based on the landowner's budget and the need/
desire for a planting, he or she will decide on
the size of planting and level of service to be
impl emented .

Upon signing the contract agreement and
receipt of the initial payment (depending upon the
season), work can begin immediately. Actual instal-
lation of tree shades can be seen in figure 1.

The types of conservation plantings Trees
Unlimited has implemented include field and farm-
stead windbreaks, wildlife habitats, Christmas tree
plantations, and fruit orchards. The designs
conform to SCS and/or CSFS specifications.

Table 1. --Average prices charged to planting

customers based on a planting of 200 to 300
trees and shrubs.

Services and products

Price charged
per tree

Site visit 0
Planting and/or irrigation design (total) 75.00

Site preparation--Simazine application 1.10

Site preparati on--Rototi 1 1 i ng .80

Plow & disk (CSFS rented equipment) 1.80

Planting (manual or by machine) 1.25

Fertilizer tablet, installed .25

Plastic rabbit guard, installed .80

Wooden tree shades, installed .80

Drip irrigation system, installation 1.00

Drip irrigation system, materials 2.20

Wood chip mulch, installed 1.10

Polypropylene mulch, installed 3.90

Herbicide application. Roundup .50

Insecticide spray .40

■''These prices are the base amount for work
within a 20-mile radius of Ft. Collins or Long-
mont , Colorado. For each 10 miles beyond the
radius, the base price is increased 20%. These
price| are for services to seedling plants.

This is an estimate based on actual amounts
of materials used on past plantings; used here for
preliminary estimate.

Unlimited stocks a full line of materials for sale
and installation. This accounts for a large per-
centage of material sales annually.

Providing these services on most of the
plantings has yielded survival rates, on an aver-
age, of greater than 95% into the second year. An
example of a high level of service, i.e., combin-
ing several products to contribute to seedling
survival, can be seen in figure 2.

Figure 2. — Close up of a pinyon pine seedling,
showing plastic rodent guard, tree shade,
drip irrigation pipe, and wood chip mulch.

Figure 1 .--Instal 1 ation of wooden tree shades on a
3-row windbreak near Boulder, Colorado.

Another important form of conservation in
Colorado is water conservation. On a tree plant-
ing great amounts of water (plus time, water
costs, and pumping costs) can be saved through
employing a drip irrigation system. Trees

PROGRAM PROMOTION

Trees Unlimited has a small advertising
budget and relies in large part on the cooperating
agencies' active referrals for business. The
program also utilizes press releases and news
announcements through the local radio stations and
newspapers. Booths at country fairs shared with
soil districts have helped for exposure. The soil
districts and agency district offices also keep
Trees Unlimited's brochures to hand out. Mass
mailing to targeted areas, telephone contacts, and
site visits make up most of the winter duties.

INVOLVEMENT WITH NURSERIES

Trees Unlimited contracted for planting
almost 8,000 seedling trees in 1987, both bareroot
and containerized. The bulk of these were pur-
chased from the CSFS Nursery in Ft. Collins,

Colorado. Most seedlings sold by this nursery are
either picked up by the customer on specific days
or shipped out during a short time period each
spring. With a schedule such as this, it might be
inconvenient, if not impossible, for a program
such as Trees Unlimited to interact with a nursery
if the nursery policy were inflexible. Due to the
nature of Trees Unlimited's business, planting
time is extended, usually filling all of April and
May. The trees must be stored during that period,
yet be available to the planter every day. A
workable arrangement has been made for storage and
pickup, both from the nursery and from a CSFS
district office 50 miles away, which provides
'similar storage facilities.

Other seedling survival products and chemi-
cals are often purchased through a few of the
local commercial nurseries.

Occasionally, larger planting stock is
desired by the customers, and that is available
everywhere. For the most part, the seedling-size
planting material has the best combination of

hardiness, vigor, size, ease of planting, and
affordabi 1 ity .

THE FUTURE

As all of the people involved with Trees
Unlimited agree, this is a program which is valu-
able and necessary in this area. It fills an
important niche, providing the link between the
seedling producer and consumer. It is a new pro-
gram and will continue to depend on all of the
involved parties to promote it. It is not a well-
known name yet, and most potential customers do
not know such a program exists. For that reason,
it is felt that if this type of "total tree care"
program were to be initiated in any certain area,
it had best be allied in some way to an existing,
known channel or outlet of seedlings. Publicity
is usually the limiting factor to growth of a worth-
while business, and the cooperation and support of
the area agencies are essential to the success and
growth of such an experimental program.

The Potential of Soil Solarization in Nurseries
to Control Soilborne Diseases^

Kenneth E. Conway^' ^

Abstract . --Use of clear polyethylene sheeting to heat
soil, through the technique called soil solarization, is being
evaluated as a method to control soilborne pathogens at the
Oklahoma Division of Forestry Nursery and at Stillwater, OK.
Studies are directed at the effects of solarization on
population densities of Pythium spp., Macrophomina phaseolina,
and Sclerot ium rolf sii . Soil temperatures under polyethylene
sheeting during August-September at the Stillwater location
reached maxima of 10 to 12 C greater than bare ground controls.

INTRODUCTION

Soilborne diseases incited by several genera
of fungi can be economically destructive in a
forest nursery. Pathogens of particular impor-
tance in Oklahoma are: Fusar ium spp., Pythium
spp. , Rhi zoctonia solani , Sclerotium rolf sii , and
Macrophomina phaseolina . Techniques used to
control these pathogens have included crop rota-
tion, fungicides (seed treatments, broadcast
applications, and drenches), and soil fumigation.
Each has its limitations due to the wide host range
of soilborne pathogens, environmental contamination,
or economics. The use of thin, clear polyethylene
sheeting to transfer solar energy to soil to
increase soil temperature is an alternative tech-
nique that needs to be investigated for use in the
nursery.

This technique is called soil solarization
and is based on our knowledge of thermal inactiva-
tion of soilborne organisms (Table 1). A 30 minute
exposure to temperatures of 66 C will destroy most
pathogenic bacteria and fungi. Pullman, et al.
(1981) explored the relationships between increased
temperatures and length of exposure to those tem-
peratures on the survival of several soilborne
fungi. Temperatures of 37 C for 18-28 days were
needed to reach LDqq levels (90%) reduction in
populations) for Pythium u 1 1 imum and Verticillium

^Paper presented at the 1987 Intermountain Forest
Nursery Association Meeting. [Oklahoma City,
Oklahoma, August 10-14, 1987].
^Professor. Department of Plant Pathology,
Oklahoma State University, Stillwater, OK
74078-0285. Professional Paper 2535. Oklahoma
Agricultural Experiment Station, Oklahoma State
University .

^The interest and support of the Oklahoma
Department of Agriculture, Division of Forestry,
Oklahoma City, is gratefully acknowledged.

dahliae . However, when temperatures were
increased to 50 C, LDgg levels were achieved in
27-33 minutes. Therefore, lower temperatures can
reduce populations of soilborne pathogens, but
longer exposure times will be necessary.

Maximum soil temperatures of 60 C have been
reported at depths of 5 cm in soil using solariza-
tion (Pullman, et al. 1981). However, these maxima
are attained for only short periods of time.
Reduction of population densities of soilborne
pathogens is more realistically achieved by
increasing soil temperatures 5 to 10 C above normal
for an extended period of time. The effect of
solarization on soilborne pathogens is a chronic
effect that weakens and debilitates the survival
structures (conidia, sclerotia, etc.) of these
fungi. Other soil organisms are more thermo-
tolerant and are not affected by solarization.
These residual organisms multiply and prevent the
recolonization of soil by the pathogen after solar-
ization.

Table 1 . --Temperatures required to inactivate
pests in compost soils^

Temperatures"
Pests (F°) (C°)
Nematodes 120 49
Damping-Off Organisms 130 54
Most Pathogenic Bacteria and Fungi 150 66
Soil Insects and Most Viruses 160 71
Most Weed Seeds 175 79
Resistant Weeds and Viruses 212 100

^Modified from Baker and Cook, 1974
''Temperatures maintain for a minimum
of 30 mimutes

Soil solarization has been used successfully

to control a number of pathogens in various
cropping systems (Conway, et al. 1983; Grinstein,
et al. 1979; Jacobsohn, 1980; Katan, et al.

1983) . Other research has indicated control of
nematodes, weeds, and growth enhancement of crops
planted in solarized soil (Heald and Robinson,
1987; Jacobsohn, et al. 1980; Grinstein, et al.
1979; Stapleton and DeVay, 1984). There have also
been studies in which control of soilborne diseases
was not achieved, particularly for Macrophomina
phaseolina (McCain, et al. 1982; Mihail and Alcorn,

1984) . Charcoal root rot, incited by M. phaseolina ,
has been a severe problem in southern tree nursery
production. Unfortunately, reports on the use of
solarization in forest nurseries are very limited.
Hildebrand (1985a, 1985b) used soil solarization

to reduce levels of Pythium and Fusarium spp. and
weed seeds in Colorado and Nebraska forest
nurseries. She estimated that, compared to chemi-
cal fumigation, solarization saved approximately
$350.00/A in production costs.

In order to evaluate soil solarization as a
technique to control soilborne diseases, experi-
ments were initiated in 1986 at the Oklahoma
Forestry Division Nursery at Washington, OK, by
Mr. Mark Miles, a graduate student in the Depart-
ment of Plant Pathology at Oklahoma State Univer-
sity. Additional experiments were performed at
Stillwater, OK. Although much of this work is
preliminary and will be used for Mr. Miles' M.S.
thesis, a generalized overview of the research is
presented below.

METHODS

Previous work (Conway, unpublished) has
indicated that Pythium irregulare and Fusarium
spp. were the primary soilborne pathogens at the
Forest Nursery. Recently, stunted sycamore and
Virginia pine seedlings were removed from the
Nursery and isolations from the roots indicated
that M. phaseolina was also an active pathogen.
At Stillwater, populations of Sclerotium rolf sii
and M. phaseolina have been documented in our
apple seedling nursery (Conway and Tomasino,
1987; Tomasino and Conway, 1987). To ascertain
the effectiveness of solarization, populations of
Pythium spp. and M. phaseolina at the Forest
Nursery, and of ^. rolf sii and M. phaseolina at
Stillwater will be enumerated before and after
solarization.

Solarization experiments were performed at
the Forest Nursery during April-May 1986 and
August-September 1987. Experiments at Stillwater
were conducted during August-September 1986 and
1987. In 1986, temperature data were collected
through use of a system developed by Dr. V.
Pederson, North Dakota State University. The
computer program was modified to allow for 22
separate temperature probes.

Prior to placement of the polyethylene
sheets, soil samples were '■andomly removed from
all plots and stored at 4 C. Soil was bulked and
thoroughly mixed before subsamples were removed.

Population densities were determined for Pythium
spp. and M^. phaseolina using selective media
(Conway, 1985; Campbell and Nelson, 1986). At
Stillwater, spun-bound polyester packets contain-
ing 50 sclerotia of S^. rolf sii were placed at 0, 5,
10, and 15 cm depths in soil to be solarized or
used as controls. All soils were moistened prior
to solarization. At Stillwater, drip irrigation
was installed beneath the polyethylene sheets.
Temperature probes were buried at 2, 4, 12, and 20
cm depths in soils of both solarized and control
plots. The computer was programmed to record input
from each probe every 30 minutes. Polyethylene
sheets (4 mil thick) were applied to the plots
using a mulch-laying apparatus. Appropriate
sections of the polyethylene sheet within the row
were removed to provide for control plots. Solar-
ization lasted for approximately 6 weeks and soil
samples were, again, randomly collected to deter-
mine densities of selected pathogens. Packets
containing sclerotia of S^. rolf sii were also
removed, at that time, and percent viability was
determined .

RESULTS AND DISCUSSION

Weather during April-May 1986 at the Nursery
was unusually cloudy and greater than average
precipitation occurred. On clear days, soil
temperature at a depth, of 4 cm in solarized
plots reached 49-50 C with a daily average of
only 4 hr during which temperatures were greater
than 37 C. Nonsolarized soils at the same depth
attained temperatures of only 24-32 C. Popula-
tion densities of selected fungi have been deter-
mined but differences among treatments have not
been analyzed.

At the Stillwater location during August
1986, solarized plots reached temperatures of
57 C, with 6 to 7 hr greater than 45 C, at 4 cm
depths. Non- solarized soils reached a maximum of
45-46 C. Packets containing sclerotia of ^.
rolf sii were retrieved from the soil after 4 weeks.
Viability of sclerotia was determined by placing
sclerotia on moistened filter paper in petri dishes
and observing germination. No significant differ-
ences in viability between solarized and non-
solarized soils were found at that time.

Soil solarization will not be a panacea for
all nursery problems related to soilborne fungal
pathogens, nematodes and weed seeds. Problems of
polyethylene residue are similar to those
involved with the use of chemical fumigants.
Another concern is that soil solarization may not
be effective in reducing population densities of
particular fungi, such as Macrophomina phaseolina .
In order to study this further, we have initiated
laboratory experiments to determine the thermal
death points in soil of Pythium irregulare isolated
from the Nursery and isolates of M. phaseolina from
several different hosts. Analysis of these data
will enable us to make predictions regarding the
effectiveness of solarization in the control of
these pathogens.

To improve the effectiveness of soil solariza-
tion, future research should involve the integra-
tion of solarization with biological control agents
(Elad, et al. 1980), the use of crop residue
amendments (Ramirez-Villapudua and Munnecke,
1987), and the use of ammonia-based fertilizers.
Data should be collected on the total effect of
solarization and should include reductions in
pathogen (including nematodes), weed and insect
population densities.

Although our work is preliminary, we feel
that we are in an exciting area of research, one
that may have very real benefits for nursery
production and management.

LITERATURE CITED

Baker, K.F., and R.J. Cook. 1974. Biological
control of plant pathogens. 433 p. W.H.
Freeman and Co., San Francisco, CA.

Campbell, C.L. and L.A. Nelson. 1986.

Evaluation of an assay for quantifying
populations of sclerotia of Macrophomina
phaseolina for soil. Plant Disease
70:645-647.

Conway, K.E. 1985. Selective medium for the

isolation of Pythium spp. from soil. Plant
Disease 69:393-395.

Conway, K.E., M.J. Martin, and H.A. Melouk.

1983. The potential of soil solarization
to control Verticillium dahliae in Oklahoma.
Proc. Okla. Acad. Sci. 63:25-27.

Conway, K.E. and S.F. Tomasino. 1987.

Evaluation of mulches to control southern
blight of apple seedlings. Biol, and
Cultural Tests. 2:7.

Elad, Y., J. Katan, and I. Chet. 1980.

Physical, biological, and chemical control
integrated for soilborne diseases in
potatoes. Phytopathology 70:418-422.

Grinstein, A., J. Katan, A. Abdul-Razik, 0.
Zeydan, and Y. Elad. 1979. Control of
Sclerotium rolf sii and weeds in peanuts by
solar heating of soil. Plant Dis. Reptr.
63: 1056-1059.

Heald, CM. and A.F. Robinson. 1987. Effects of
soil solarization on Rotylenchulus
reni f ormis in the lower Rio Grande Valley of
Texas. J. Nematology 19:93-103.

Hildebrand, D.A. 1985a. Soil solar heating for
control of damping-off fungi and weeds at
the Colorado State Forest Service Nursery.
Planters' Notes 36:28-34.

Hildebrand, D.A. 1985b. Soil solar heating for
reduction in populations of Pythium,
Fusar ium , nematodes, and weeds at the U.S.
Forest Service Bessey Tree Nursery, Halsey,
Nebraska. USDA For. Serv., Rocky Mt .
Region, Timber, For. Pest & Coop. For.
Manag., Tech. Rep. R2-34, 24pp.

Jacobsohn, R. , A. Greenberger, J. Katan, M. Levi,
and H. Alon. 1980. Control of Egyptian
broomrape and other weeds by means of solar
heating of the soil by polyethylene
mulching. Weed Sci. 28:312-316.

Katan, J., G. Fishier, and A. Grinstein. 1983.
Short and long-term effects of soil
solarization and crop sequence on Fusarium
wilt and yield of cotton in Israel.
Phytopathology 73:1215-1219.

McCain, A.H., R.V. Bega, and J.L. Jenkinson.
1982. Solar heating fails to control
Macrophomina phaseolina . Phytopathology
72:985. (Abstr).

Mihail, J.D. and S.M. Alcorn. 1984. Effects of
soil solarization on Macrophomina phaseolina
and Sclerotium rolf sii . Plant Disease
68: 156-159.

Pullman, G.S., J.E. DeVay, and R.H. Garber.

1981. Soil solarization and thermal death:
a logarithmic relationship between time and
temperature for four soil-borne plant
pathogens. Phytopathology 71:959-964.

Ramirez-Villapudua, J., and D.E. Munnecke. 1987.
Control of cabbage yellows (Fusarium
oxysporum f. sp. conglut inans ) by solar
heating of field soils amended with dry
cabbage residues. Plant Disease 71:217-221.

Stapleton, J.J. and J.E. DeVay. 1984. Thermal
components of soil solarization as related
to changes in soil and root microflora and
increased plant growth response.
Phytopathology 74:255-259.

Tomasino, S.F. and K.E. Conway. 1987. Spatial
pattern, inoculum density-disease incidence
relationship, and population dynamics of
Sclerotium rolf sii on apple rootstock.
Plant Disease 71:719-724.

Seedling Production at Oklahoma Forestry Division
Forest Regeneration Center^

Clark D. Fleege^

The Oklahoma Department of Agriculture's Forestry Divi-
sion has been supplying tree seedlings for conservation plant-
ings since 1927. The Forest Regeneration Center near Goldsby
distributes 4 - 4^ million seedlings annually. This includes
bareroot one year old hardwoods, bareroot one and two year old
conifers. The Division also manages a southern pine seed or-
chard.

The Oklahoma Forestry Division has been
growing and distributing tree and shrub seed-
lings for Oklahoma's private landowners for
almost as long as it has been in existance.
From a meager beginning at Stillwater (in
northcentral Oklahoma) in 1927, Oklahoma's
State Tree Nursery moved first to Stringtown
in 1938, and then to its present location
south of Norman in 1945.

The Forest Regeneration Center at Washing-
ton produces hardwoods and conifer seedlings.
It was formerly one of two nurseries operated
by the Forestry Division. From 1949 until
1977, the Division grew southern pine seedlings
at its nursery in southeast Oklahoma. Because
of the need for modernization, and the high
cost of operating two nurseries, a decision
was made to contract the production of southern
pine seedlings to the Weyerhaueser Company
nursery in southeast Oklahoma.

The purpose of the Regeneration Center
is to provide Oklahoma's private landowners
with quality tree and shrub seedlings for
planting on their lands. These seedlings
are sold state-wide for a variety of purposes.
Including wildlife habitat improvement, wind-
break establishment, fuelwood, postlots, ero-
sion control plantings, Christmas trees and
timber production.

■^Paper presented at the Intermountain
Forest Nursery Association, 1987 annual meeting,
Oklahoma City, Oklahoma, August 10-14, 1987.

2ciark D. Fl eege. Nursery Superintendent,
Oklahoma Department of Agriculture, Forestry
Division .

The Regeneration Center had 65 acres under
production. Currently we produce 20 species
of hardwoods and 9 conifer species. Our annual
production is 4 to 4^ million seedlings.
Currently the Forestry Division contracts with
Weyerhaeuser to produce one year old improved
loblolly pine seedlings. We also contract
with Colo-Hydro of Longmont, Colorado for
the production of conifer tublings used for
planting on selected shallow, droughty soils
of western Oklahoma.

The soil is a sandy loam "second-bottom
land" soil, slightly basic. Each year we
have soil samples analyzed through the State
University of New York and amend each field
accordingly to reach optimum nutrient levels
for seedling production. For example, we
will add sulfur to lower ph on specific fields;
and manure and sawdust on every field to raise
organic matter and improve soil texture.
Fields that are not in crop production are
planted to sudan grass cover crop in the spring.
The cover crop will be mowed regularly through-
out the growing season. Prior to winter the
cover crop will be plowed and the field will
be prepared for a spring planting. Generally,
we have a field in cover crop every other
year. We have two wells that pump to a 210,000
gallon storage tank from which all field irri-
gation is pumped. The entire nursery can
be irrigated through a network of underground
mainlines and field groundlines.

The seed for producing our crop is either
collected from proven quality local Oklahoma
sources; or purchased from reputable seed
dealers, source-identified.

We have been working closely with the Soil
Conservation Service/P.Iant Materials Centers
and Oklahoma State University in identifying
those varieties that will exhibit specific
traits deemed desirable, such as faster growth
rate, drought-tolerance, frost-hardiness,
disease-resistance, etc. Several varieties
have been identified and seed production areas
of those varieties have been established
near the Regeneration Center. All seed is
processed and stored at the seed extraction
building.

All the hardwood species we produce are
one year old seedlings. Seven species are
fall or winter sown, and the remainder are
stratified and planted in the spring. Because
of our longer growing season, some species
can become quite tall. For example it is
more the rule than the exception for black
locust sown in mid-June to be seven feet tall
by October with little if any irrigation or
fertilization. Of the nine species of conifers
we produce, six are spring sown, two year
old seedlings. Through fumigation and proper
soil management we anticipate producing our
improved Virginia pine and limited quantities
of improved loblolly pine in just one season.
The remaining conifer, bald cypress, can easily
reach plantable size in one season. Immediate-
ly after the beds are sown, we apply a light
layer of fine sawdust followed by a layer
of hydromulch. This is done to help retain
soil moisture, reduce soil temperatures and
prevent "wash-out" in the event of severe
spring showers.

Weeds are fierce competitors for soil
moisture and nutrients. We try to' maintain
a weed-free nursery through the use of regi-
stered herbicides, mechanical weeding machines
and seasonal labor. Over the past 10 years
we have been working with State University
of New York and Dr. Larry Abrahamson in testing
those herbicides that will control weeds and
not effect seedlings. The effort has produced
outstanding results; we have 90% of our tree
species under chemical-weed control. The
program is still on-going for those newly
acquired species. Regularly when the seedlings
are 4-6 inches in height, we will use a mechan-
ical brush hoe to control weeds in seedbeds.

Not only are weeds controlled, but an addition-
al benefit is the break-up of the soil crust
in the seedbed. Our last line of defence
in the great weed wars are seasonal personnel,
armed with hoes, weeding knives and/or round-
up herbicide applicators. During the course
of the summer our temporary crew numbers
5-7 people.

A comprehensive lateral root pruning
and root wrenching schedule is followed to
develop fibrous root systems of conifers and
hardwoods for improved outplanting survival.

The seedling harvest season at this nur-
sery begins late November/early December and
ends mid- to late March. Winters in Oklahoma
tend to be wet and cold with occassional snow.
Usually in January we experience a two to
three week freeze and all harvesting comes
to a halt. After that time the ground thaws
and harvesting resumes. In the past a Grayco
Seedling Harvester was used to lift the seed-
lings; now we use exclusively Fobro lifters.
All seedlings are processed and counted before
shipment. The seedlings are graded as per
accepted industry standards for height and
caliper, grouped into 50 's and machine-tied.
A heeling-bed is used for temporary storage
of hardwoods. The seedling cooler is used
for storing remaining hardwoods and all conifers.
The temperature of the cooler is 34 degrees
and the relative humidity is 100%.

The majority of our tree sales are to
small rural landowners; average order size
is about 500 seedlings. Cooperators will
receive their seedlings packages either through
the United Parcel Service (UPS), or by picking
them up at the nursery. Friday is the desig-
nated pick-up day and those that are included
are notified a week in advance. This method
of using UPS to ship seedlings and the one
designated pick-up day/week is quite effective.

For the past two seasons, with the cooper-
ation of the Soil Conservation Service and
the State Conservation Commission we have
located numerous seedling distribution sites
in communities statewide. By distributing
the seedlings directly to the landowners from
our refrigerated seedling trucks, we hope
for greater out-planting survival.

Annually Forestry Division service forest-
ers will conduct comprehensive seedling survi-
val investigations at numerous planting sites
statewide. This information will be used
to help evaluate the cultural practices used
for producing seedlings at the nursery. We
feel these survival studies are necessary
for the continued production of quality seed-
lings. Service foresters also assist in seed
location and collection. They develop and
help implement planting plans for rural land-
owners. Our service foresters serve as a
valuable extension of the Regeneration Center.

The Forestry Division manages a genetical-
ly improved southern pine seed orchard in
southeast Oklahoma. We are utilizing the
advancing front concept which involves the
most productive families currently available.
The initial orchards were established in the
mid-60's and currently coming into full produc-
tion. This provides the landowners of Oklahoma
with the only available local source of geneti-
cally improved loblolly and shortleaf pine
seedlings which have been thoroughly field
tested through progeny tests to determine
the most productive sources.

These seedlings will give higher yields of
high quality timber in a shorter amount of
time than "woods run" seedlings. The Division
is a member of Western Gulf Forest Tree Improve-
ment Program (WGFTIP), This is a cooperative
whose members include other state and private
organizations interested in the genetic improve-
ment of forest trees. Currently 100% of all
shortleaf and loblolly pine distributed by
the Division is genetically improved. Through

continued research and testing with WGFTIP
and Oklahoma State University, the Oklahoma
Forestry Division will continue to provide
the very best planting material available
to the landowners of Oklahoma.

Through proper soil management, timely
and appropriate cultural practices and quality
control, we are ensuring the continued produc-
tion of quality tree and shrub seedlings for
conservation plantings in Oklahoma.

Priming Treatments to Improve Pine Seed Vigor^

S. W. Hallgren^

Abstract. — Osmotic priming improved both final
germination and rapidity of germination in loblolly pine
and showed a detrimental effect or no effect on slash pine
seeds. The beneficial effects of priming were lowest for
stratified seeds and greatest at a low germination
temperature .

INTRODUCTION

Nursery managers prefer to work with high-
vigor seed lots that show rapid uniform
germination and produce vigorous seedlings under
a wide range of conditions. Seedling costs are
lower because there are fewer culls and uniform
stands of seedlings are easier to manage. Thus,
there is a strong incentive to improve
techniques for controlling and manipulating seed
vigor .

Seed priming has shown promise as a
technique for improving seed vigor in numerous
agricultural and horticultural species
(Heydecker and Coolbear 1977, Heydecker et al.
1973). The technique has been used to improve
germination in cold soils (0' Sullivan and Bouw
1984, Sachs 1977), to alleviate thermodormancy
(Valdes et al. 1985, Guedes and Cantliffe 1980)
and to increase rate and uniformity of crop
emergence (Heydecker and Coolbear 1977,
Heydecker et al. 1973, Holley et al. 1984).
Seeds are imbibed in an osmoticum that allows
all the processes of germination to proceed to
completion except radical emergence. The
treatment is long enough to bring all the seeds
to the same point, posied just before the last
step in germination. Upon termination of the
treatment, seeds are introduced to water and the
germination process proceeds rapidly to
completion (Bewley and Black 1985) .

Paper presented at the Intermountain Nursery
Association meeting [Oklahoma City, August 10-
14, 1987], Professional paper No. P-2539 of the
Agriculture Experiment Station, Oklahoma State
University .

S. W. Hallgren is Associate Professor of
Forestry at Oklahoma State University,
Stillwater.

Previous work on priming required rather
cumbersome techniques for bringing the seed in
contact with the osmoticum that worked well for
small quantities of seed (Heydecker and Coolbear
1977). Recently, a seed priming system was
developed at Oklahoma State University that
proved to be effective in priming vegetable
seeds and could be upgraded to handle large
quantities of seed. Basically, seeds are primed
In columns of osmoticum that are vigorously
aerated to insure adequate gas exchange for the
seeds (Akers and Holley 1986, Akers et al. 1984,
Holley et al. 1984).

This system was tested with loblolly
(Pinus taeda L.) and slash pine (Pinus elliottii
Engelm.) seed and the results were promising.
Some of the preliminary results are presented
here. A more complete evaluation of the
technique is being prepared for publication in a
scientific journal.

MATERIALS AND METHODS

Seeds used in the study were from single
bulk lots of improved loblolly pine and slash
pine collected in 1985 and supplied by the Texas
Forest Service. Prior to priming the seeds were
divided into two equal groups, one to remain in
cold storage and one to receive a cold moist
stratification treatment for 53 days.

The seeds were primed in transparent
columns of vigorously aerated priming solution
at 25°C (Akers and Holley 1986). The solutions
were prepared from polyethylene glycol,
molecular weight 8000, and water to have a water
potential of -1.0 MPa. Each column contained
300 ml of solution and 400 seeds. Solutions
were changed daily at first and every other day
later in the 11 day treatment period. Light was
not excluded from the priming columns. One

group of seeds was not primed and was given an
additional 11 days of stratification for a total
of 64 days .

Following 11 days of priming the seeds
were washed and divided into groups to be placed
in two germinators, one at constant 25 C and
another at 15 C. At 25 C the temperature is
near optimum for germination of the southern
pines and 15 C is considered stressful
(Association of Official Seed Analysts 1981,
Dunlap and Barnett 1984). The seeds received
natural lighting during germination. The seeds
were arranged in 4 replicates of 50 seeds on
moist filter paper and the layout was a
randomized complete block design in each
Incubator.

Germination was counted for 37 days,
everyday at first and less frequently as
germination slowed. A seed was considered
germinated when the growing radical began to
show geotroplc curvature (Dunlap and Barnett
1984). Analysis of variance and the Least
Significant Difference were used to determine
the significance of treatment effects on final
percent germination and the number of days to
reach 50 percent of the final total germination
(Steel and Torrie 1980).

RESULTS

The effect of priming on final germination
for loblolly pine at 25 C was an Increase of
nearly 50 percent for unstratified seeds and no
change for stratified seeds (Table 1). Days to
50 percent germination was reduced by more than
50 percent by priming for both stratified and

Table 1. Effects of priming on final percent germination
and days to 50 percent germination for stratified and
unstratified loblolly and slash pine seeds germinated
at 25°C.

Final
Percent Germination

Days to
50% Germination

Stratified
No Yes

Loblolly Pine
Not Primed

^3 b

8.6 a

4.6 a

Primed

79 a

3.1 b

2.0 b

Slash Pine

Not Primed

88 a

92 a

4.8

3.8

Primed

72 b

66 b

4.4

3.6

For each species and stratification treatment means followed
by the same letter are not. different at the 5 percent level; '
stratification treatment significant at the 5 percent level.

unstratified seeds. Stratification alone
increased final germination by 80 percent and
reduced days to 50 percent germination by nearly
50 percent.

^In contrast, slash pine final germination
at 25 C showed a reduction due to priming of 18
and 28 percent for unstratified and stratified
seeds. Stratification alone had no effect on
percent germination and neither stratification
nor priming affected days to 50 percent
germination.

At 15°C loblolly pine showed only 2
percent germination when unprimed and
unstratified (Table 2). Final germination was
increased by stratification to 89 percent and by
priming to 35 percent, and priming had no effect
on stratified seeds. Days to 50 percent
germination for stratified seeds was reduced by
60 percent by priming.

Table 2. Effects of priming on final percent germination
and days to 50 percent germination for stratified and
unstratified loblolly and slash pine seeds germinated
at 15°C.

Final
Percent Germination

Days to
50% Germination

Stratified
No Yes

Loblolly Pine
Not Primed

^2 b

13.4 a

Primed

35 a

8.1

5.4 b

Slash Pine

Not Primed

88 a*

13.2

IX. 3

Primed

44 b

12.4

13.4

For each species and stratification treatment means followed
by the same letter are not different at the 5 percent level; *
stratification treatment significant at the 5 percent level.

The effect of priming on percent
germination for slash pine at 15 C was nil for
unstratified seed and a 50 percent reduction for
stratified seed?. Stratification alone more
than doubled percent germination. Days to 50
percent germination was unaffected by both
priming and stratification.

DISCUSSION

The results of this study demonstrated
that osmotic priming improves the vigor of
loblolly pine seeds (Table 1 and 2). Osmotic
priming is known to have beneficial effect on

the vigor of seeds of many agricultural crops
(Heydecker and Coolbear 1977). There has been
very little work done with tree seeds.

Osmotic priming, like stratification, can
improve both final germination and rapidity of
germination. The beneficial effects of priming
are less if the seeds are stratified before
priming, indicating that both treatments may
affect some of the same germination processes.

The beneficial effects of priming for
loblolly pine were even greater at a low
germination temperature than at a nearly optimum
temperature (Table 2). These results are
consistent with findings for agricultural crops
that priming can improve germination at
suboptimum temperatures (0' Sullivan and Bouw
1984 and Sachs 1977). Apparently loblolly pine
seeds are especially sensitive to low
temperature stress during germination (Dunlap
and Barnett 1984) and osmotic priming can be a
practical option for overcoming the sluggish
germination at low temperatures.

The results presented here are
Inconsistent with the previous findings that
osmotic priming improved germination of slash
pine seeds (Haridi 1985). The two studies are
not entirely comparable since different
techniques were employed and the priming
treatment ran for nearly twice as long in the
current study as in the prior one. There were
many ways the techniques used in the current
study could be adjusted to meet the needs of
different species including changes in
temperature, solution concentration, oxygen
levels, types of osmoticum and length of
treatment .

It is well known that loblolly pine and
slash pine have different stratification
requirements for removal of dormancy and it is
not surprising that they show different
responses to the same osmotic priming treatment
(Krugman and Jenkinson 1974).

LITERATURE CITED

Akers, S. W. and K. E. Holley. 1986.
SPS: A system for priming seed
using aerated polyethylene glycol
or salt solutions. HortScience.
21:529-531.

Akers, S. W. , K. E. Holley and P. Ager.
1984. A screening process to
establish effective priming
treatments for vegetable seed.
HortScience 19:211.

Association of Official Seed Analysts.
1981. Rules for testing seeds.
Journal of Seed Technology 6:1-124.

Bewley, J. D. and M. Black. 1985.

Seeds: physiology of development

and germination.
York. 367 p.

Plenum Press, New

Dunlap, J. R. and J. P. Barnett. 1984.
Manipulating loblolly pine (Pinus
taeda L.) seed germination with
simulated moisture and temperature
stress, p. 61-74. In: Seedling
physiology and reforestation
success (M. L. Duryea and G. N.
Brown, eds.). Martimers Nijhoff/Dr.
W . Junk Pub . , Boston .

Guedes, A. C. and D. J. Cantliffe.

1980. Germination of lettuce seeds
at high temperature after seed
priming. J. Am. Soc. Hort. Sci.
105:777-781.

Haridi, M. B. 1985. Effect of osmotic
priming with polyethylene glycol on
germination of Pinus elliottii
seeds. Seed Sci. and Technol.
13:669-674.

Heydecker, W. and P. Coolbear. 1977.
Seed treatment for improved
performance-survey and attempted
prognosis. Seed Sci. and Technol.
5:353-424.

Heydecker, W. , J. Higgins and R. L.
Gulliver. 1973. Accelerated
germination by osmotic seed
treatment. Nature 246:42-44.

Holley, K. E., S. W. Akers, J. E.
Motes and R. W. McNew. 1984.
Field emergence and yield
of carrot (Daucus carota L.
"Royal Chantenay") seed primed
in aerated KNO, solutions.
HortScience 19:214.

Krugman, S. L. and J. L. Jenkinson.

1974. Pinus L. Pine p. 598-638.
In: Seeds of woody plants in the
United States. USDA Forest Service
Agric. Handb. 450.

O'Sullivan, J. and W. J. Bouw. 1984.
Pepper seed treatment for low-
temperature germination. Can. J.
Plant Sci. 64:387-393.

Sachs, M. 1977. Priming of watermelon
seeds for low-temperature
germination. J. Amer. Soc. Hort.
Sci. 102:173-178.

Steel, R.G.D. and J. H. Torrie. 1980.
Principles and procedures of
statistics. 2nd Ed. McGraw-Hill,
New York. 633 p.

Valdes, V. M. , K. J. Bradford and K. S.
Mayberry. 1985. Alleviation of
thermodormancy in coated lettuce
seeds by seed priming. HortScience
20:1112-1114.

Effects of Nursery Density on Shortleaf Pine^

John C. Brissette and William C. Carlson^

Abstract . — A technique to determine the effective
nursery bed density of individual seedlings was developed
and then used to evaluate density influence on shortleaf
pine {Pinus eahinata H±ll.) bare-root seedlings. At
lifting, mean height had increased while mean root collar
diameter and root volume had decreased with increasing
effective density. After the first growing season,
seedlings produced at lower effective densities exhibited
greater height and diameter growth than seedlings grown at
higher effective densities.

INTRODUCTION

Shortleaf pine {Finns eahinata Mill.) is the
most important species used for artificial
regeneration on the Ouachita and Ozark National
Forests (Kitchens 1987). Approximately 12 million
seedlings are planted annually on about 7,000
hectares of the two forests. Although artificial
regeneration of shortleaf pine represents a large
investment on the two forests, success of the
program has been limited by poor seedling survival
and growth. Excluding the severe drought year of
1980, seedling survival has averaged about 50
percent since large-scale planting was begun in
the 1970's. The reasons for poor seedling
performance are not clear. The planting sites are
harsh, the soils are rocky, and the south and west
aspects are exposed to hot, droughty conditions
throughout the summer. However, many forest
managers do not think that difficult site
conditions alone explain the poor seedling
performance. They note that seedling quality also
must be considered. Consistent production of
quality planting stock requires a thorough
knowledge of seedling development in the nursery
and an understanding of how nursery culture
impacts field performance.

In a recent review, Barnett and others (1987)
found few references to shortleaf pine stock
quality. Two of the most enlightening items were
by Chapman (1948) and Clark and Phares (1961).

Paper presented at Intermountain Nursery
Association meeting, Oklahoma City, OK, August
10-14, 1987

Silviculturist , USDA Forest Service, Southern
Forest Experiment Station, Pineville, LA, and Tree
Physiologist, Weyerhaeuser Company, Hot Springs,
AR

The earlier paper dealt with the effects of
morphological characteristics on the survival and
initial growth of seedlings planted on old field
sites in Arkansas, Missouri, Indiana, and Ohio.
The later paper dealt with survival and growth of
the plantations in Missouri and Indiana at age 19
and 20. In general, larger diameter seedlings
performed better initially, and that early
superiority was maintained over time.

One of the most critical factors determining
seedling quality is seedbed density. Density is a
measure of competition among seedlings for growing
space and relates to their ability to receive
light, water, and nutrients. As density
increases, yield of cull seedlings increases and
average root collar diameter decreases (Shoulders
1961). Seedling weight also decreases with
increasing density. In loblolly pine (P. taeda
L.), root weight is reduced proportionately more
than shoot weight, resulting in a corresponding
decrease in root-to-shoot ratio (Harms and Langdon
1977). Mexal (1981) concluded that the biological
optimum density foj growing loblolly pine
seedlings is 200/m •

With the mechanical sowing methods in use,
and less than perfect germination, nursery bed
density is seldom uniform. Although bed density
is a useful criterion for evaluating average
seedling characteristics on a plot basis, bed
density consequence on individual seedlings is
difficult to determine.

In 1985 a study was established at
Weyerhaeuser Company's Magnolia Forest
Regeneration Center in southwest Arkansas to
address the quality of shortleaf pine planting
stock used to reforest Ouachita and Ozark Mountain
sites. The effects of nursery bed density and
fertilization on the morphology, nutrient status,
and root growth potential of seedlings from that

study were reported previously (Brissette and
Carlson 1987). Objectives of this paper are to
describe a method of determining the effective
density of individual seedlings and to compare the
morphology and subsequent first-year field
performance of seedlings grown at a range of
effective densities.

MATERIALS AND METHODS

This study was part of one designed to
evaluate nitrogen (N) and phosphorus (P)
fertilization as well as seedbed density. The
design and installation of the experiment were
described in a previous paper (Brissette and
Carlson 1987), and will be only briefly reviewed
here. There were two levels of P, five levels of
density, and four levels of N applied in a
split-split plot design with four replications.
The levels of P were the level in the soil before
the experiment and enough 0-300-0 fertilizer
incorporated prior to seedbed formation to
theoretically raise the level 150 percent. No
significant effects were attributed to the P
treatments (Brissette and Carlson 1987).

Ammonium sulphate was applied in five
biweekly topdressings at levels ranging between
55kg N/ha and 170kg N/ha. The effect of N on
morphological attributes peaked at an intermediate
level, and interacted with mean seedbed density in
its effect on root growth potential (Brissette and
Carlson 1987).

The study was sown on April 16, 1985, with
Weyerhaeuser-designed precision vacuum equipment
that sowed eight double rows of seeds. The five
target densities of living seedlings were: (1)
160/m2, (2) 230/m2, (3) 295/m2, (4) 360/m2, and
(5) A30/m2.

Actual average seedbed densities were lower
than the target densities because germination was
poorer than expected. Average density for each
level in the study was: 141/m2, 218/m2, 269/m2,
296/m2, and 296/m2, Note that the two highest
levels were the same. Although the highest
density was well below the sowing target, it was
higher than the operational level (270/m2)
recommended by Chapman (1948) but much lower than
the density (540-590/m2) suggested as a maximum by
Wakeley (1954).

Early in the study a transect was taken
across the center of each plot and one seedling
from each double drill row was permanently tagged
as a measurement tree. Thus, 1280 identified
seedlings were followed throughout the study.
Those seedlings are the basis for this paper.

To determine effective density we reasoned
that seedling shoots are most affected by other
seedlings that are closer than about 15 cm. Root
competition probably occurs at greater distances.

but we assumed that most water and nutrient uptake
is also within 15 cm. Thus, seedlings sown in
conventional drills on 15 cm spacing compete
within their own drill row and with seedlings in
adjacent drill rows. To determine the effective
density of each of the labeled seedlings the
number of seedlings in the double drill row for 15
cm on either side was added to the similar number
obtained on adjacent drill rows. The total is an
estimate of the number of seedlings with which the
measurement tree was competing.

Because competition is usually expressed as
the number of seedlings per unit area, the number
of competing seedlings was converted to number per
square meter, i.e., the effective density for each
measurement tree. The conversion was based on the
area included in obtaining the number of competing
seedlings. The measurement area was 30 cm long,
the nursery beds were 1.2 m wide with eight drill
rows. Since the seedlings from the six interior
drill rows are competing with those on either side
(three rows total) the area was calculated to be
3/8 X 1.2 m X 0.3 m = 0.135 m2. The effective
density was then calculated as the number of
competing seedlings/0.135 m2 — for example, 36
seedlings/0.135 m2 = 267 seedlings/m2 . Because
the seedlings on the outside of the nursery bed
only have one adjacent drill row (two competing
rows) their area of competition was calculated to
be 1/4 X 1.2 m X 0.3 m = 0.09 m2. Thus for a
seedling on the outside drill row competing with

19 additional seedlings, its effective density is

20 seedlings/0.09 m2 = 222 seedlings/m2 .

Each of the 1280 measurement seedlings was
labeled with an aluminum tag attached to the stem
with a wire. When the beds were laterally root
pruned prior to lifting the tags and wires caused
extensive stem damage. When the seedlings were
hand-lifted on January 20-21, 1986, 970 of the
original 1280, were undamaged. These undamaged
were measured for root collar diameter, height
(shoot length), and root volume, using the
displacement method (Burdett 1979). The seedlings
were kept in cold storage between lifting and
planting except when they were being measured.
The measurements were made in a laboratory and
required less than 5 min per seedling.

On February 7, 1986, the seedlings were
machine-planted on a sod-covered site at the J. K.
Johnson Tract of the Palustris Experimental Forest
west of Alexandria, LA. On March 5-6, 1987, the
total height and ground line diameter of all
living trees were measured. Relative growth rates
(RGR) were calculated as percent change in height
and diameter between the nursery and first-year
field measurements (field measurement-nursery
measurement/nursery measurement X 100).

Seedling morphology and first-year field
performance data were analysed by regression
techniques. The 970 trees were subdivided in 10
density classes of 97 observations each and the
means were used in the analyses.

RESULTS AND DISCUSSION

The effective densities for the 970 seedlings
ranged from 55 to 431 seedlings/m^ with a mean of
Ihb/m^ and a coefficient of variation (CV) of 30
percent. When divided into 10 subclasses of 97
seedlings each, the mean densities ranged from 123
to 365/m2 (table 1). The amount of N available
per seedling was computed by dividing the total N
applied by the effective density. It ranged from
13 to 260 mg/seedling with a mean of 47
mg/seedling. Within the density classes, mean N
ranged from 30 to 87 mg/seedling (table 1).

With density as the independent variable,
regressions with the three morphological
characteristics as dependent variables were all
significant (p<.001). Coefficients of
determination (r^) were 0.78, 0.92, and 0.98 for
height, diameter, and root volume respectively,
field performance. Under operational conditions
where the rate of N application is usually more
uniform than bed density, this relationship may be
even more important.

Nursery bed density clearly had affected
seedling morphology at time of lifting (table 1).

Table 1. — Nursery bed density effects on shortleaf pine seedling morphology and first-year
field performance

Density

Mean

Nursery

First-year

field

Relative

growth

class

density

Dia

RV -k/

Dia

-/m2-

-mg/ tree-

-mm —

--CC —

mm —

123

163

4.8

4.1

357

6.8

124

155

167

4.7

3.9

373

6.8

130

188

181

4.7

3.5

356

6.5

100

217

182

4.6

3.3

353

6.2

100

237

183

4.6

3.2

356

6.1

100

261

181

4.4

2.8

348

5.9

282

182

4.4

2.7

328

5.8

303

183

4.3

2.7

328

5.8

331

187

4.3

2.6

335

5.7

365

190

4.3

2.5

328

5.6

^2c/

.98

.78

.92

.98

.75

.97

.88

.68

— ' N = nitrogen

— RV = root volume
c/ 2

— r = coefficient of determination with mean effective density as the independent

variable, see text for individual regression equations

Determination of nutrient uptake in fertilizer
experiments requires destructive sampling. For
this study concentrations of N, P, and K in
seedling shoots were reported previously (Brissette
and Carlson 1987). Although a theoretical amount
of N was calculated for each seedling on the basis
of effective density, it cannot be confirmed.
Therefore, this paper's discussion is confined to
the effects of density. Differences due to the
four N rates applied are taken into account by
analyzing the means of the density classes that are
made up of approximately equal numbers from each N
treatment. As shown in table 1, the average amount
of N available per seedling decreases as density
increases. Thus the effects of density on an
individual seedling cannot be totally separated
from the effects of N. This relationship should be
kept in mind during the following discussion about
morphology and field performance. Under
operational conditions where the rate of N
application is usually more uniform than bed
density, this relationship may be even more important.

As mean density increased, mean height increased
while mean diameter and root volume decreased.
With density as the independent variable,
regressions with the three morphological
characteristics as dependent variables were all
significant (p<.Q01). Coefficients of
determination (r ) were 0.78, 0.92, and 0.98 for
height, diameter, and root volume respectively.

Nursery managers seldom have a seedlot or
even a species growing at the range of densities
represented in this study. For pines, managers
are most interested in densities between 215 and
325/m2. To evaluate this range in more detail, we
selected two of our density classes and compared
them with analysis of variance (ANOVA). The
classes selected from table 1 were 4 and 8. Class
4 had a mean density of 217/m2. It had a
relatively narrow range of densities of from 204
to 226/m2. Class 4 is the one just above the
biological optimum density recommended for
loblolly pine by Mexal (1981). At most nurseries

it would be considered low density. Class 8 had a
mean density of 303/m^ and a range (between 292
and 316/m^) nearly as narrow as Class 4. Class 8
would be considered moderately high density.

Seedlings from Classes 4 and 8 did not differ
significantly in height (MSE=1521, p =.905).
Although the difference in mean diameters was only
0.3 mm, it was significant (MSE=0.96, p = .020).
The 0.6 cc difference in root volume was also
significant (MSE=1.33, p< .001).

Nursery managers often evaluate their crop
quality as the percentage of seedlings that
exceeds some minimum standard. For the southern
pines, morphological seedling grades were
developed by Wakeley (1954), drawing on several
years of research results and operational
observations. These grades are still recognized
as the standard measure of southern pine seedling
quality. Three grades are defined, two plantable
and one cull, based primarily on root collar
diameters of undamaged seedlings. For shortleaf
pine the minimum diameter for plantable seedlings
(Grade 2) is 3.2 mm while the minimum for premimum
seedlings (Grade 1) is 4.8 mm. In our density
Class 4, only 3 percent of the seedlings were less
than 3.2 ram and would have been considered culls,
while in Class 8, 12 percent were culls. In Class
4, 40 percent of the seedlings were Grade 1, while
in Class 8, 30 percent were Grade 1.

Root volume is seldom evaluated operationally
but is considered one of the most important
morphological characteristics. During the period
between planting and elongation of new roots, root
volume largely determines the level of plant
moisture stress that can develop (Carlson 1986).
Larger root volumes also provide more sites for
new root growth, thus root volume has been
positively related to root growth potential in
both loblolly pine (Carlson 1986) and shortleaf
pine (Brissette and Carlson 1987). For these
reasons large root volumes are especially
important when seedlings are planted on droughty
sites. However, root volume is extremely
sensitive to nursery bed density. Across our 10
density classes, root volume decreased sharply as
density increased (fig. 1).

First-year field survival was excellent,
being 98 percent overall. Among seedbed density
classes, first-year survival was between 96 and 99
percent. Field growth was statistically related
to nursery bed density (table 1). The regression
between first-year field height an^ seedbed
density was significant (p<.005, r = 0.75). But,
unlike nursery height, field height decreased as
the density at which the seedlings were grown
increased (fig. 2). That is, the shortest trees
from the nursery were the tallest in the field
after the first growing season. First-year field
diameter was also significantly related to nursery
density (p< .001, r = 0.97). Like nursery diameter
field diameter decreased with increasing seedbed
density (fig. 3).

4.5

Dens I ty
(seed 1 1 ngs/mS )

Figure 1. — Relationship between mean effective
density and mean root volume of shortleaf
pine seedlings, n=97.

400

350

300

?i 250

200

150

100

Dens t ty
Cseed 1 1 ngs/m2 )

Figure 2. — Relationship between mean effective
density and mean shortleaf pine seedling
height at lifting (lower curve, n=97) and
after one year in the field (upper curve,
n=93-96.

In terms of RGR, changes in heights and
diameters between the nursery and the field were
also related to nursery density (table 1). For

the 970 trees, the mean RGR for height in the
field was 97 percent; 100 percent represents a
doubling in size. When regressed with seedbed
density the relationship was significant (p<.001,
r^ - 0.88). Diameter RGR was not nearly as great
with an overall mean of 38 percent, but was also
significantly realted to nursery density (p< .005,
r^ - 0.68). For both height and diameter, RGR in
the field declined with increasing nursery density
(fig. A).

4 . 0 I ' -i— > 1 1 I

S Q Q Q CJ Q

O in a in C3 in Q

— fvi ru m CO T

Dons i ty
( seed I ( ngs/m2 )

Figure 3. — Relationship between mean effective

density and mean shortleaf pine seedling root
collar diameter at lifting (lower curve,
n=97 and ground line diameter after one
growing season (upper curve, n=93-96).

ise r

25 1 1 _i 1 1 1 1

G9 S S) S Q C9 S

S in Q in Q in Q

-• — (M (M m m T

Dens t ty
(seed I t ngs/m2 )

Figure A. — Relationship between mean effective

density and mean relatilve first-year growth
rates (field measurement-nursery
measurement/nursery measurement X 100) for
seedling height (upper curve, n=93-96) and
diameter (lower curve, n=93-96).

Both nursery managers and foresters benefit
when they agree on a set of specifications for a
target seedling that will give the desired
performance on a particular planting site. Target
seedling specifications differ somewhat from
seedling grades because targets are based on
performance goals. Thus target specifications are
often more stringent than morphological grades,
which are usually based on a minimum performance
level. One proposed goal for southern pines is a
doubling in height during the first growing season
in the field (Brissette 1985). Data from this
study can be used to help specify a target
seedling that will meet that goal. The regression
equation for relative height growth in terms of
nursery density (X = seedlings /m^) is:

RGR HT = 150.5 - 0.21537X, r^ = 0.88

To achieve a doubling in height (100 percent
change), the equation predicts a density of
235/m . The equations for nursery height (HT),
diameter (DIA), and root volume (RV), in relation
to density are:

HT = 156.2 + 0.09608X, r^ = 0.78

DIA = 5.1 -0.00237X, r^ = 0.92

RV = 5.9 -0.01648X + 0.00002x2, r^ = 0.98

These equations predict that a seedling
capable of doubling in height under the conditions
of this study: (a) is no more than 179 mm tall
(minimum mean height in the data set was 163 mm),
(b) is at least 4.5 mm in root collar diameter,
and (c) has a root volume of at least 3.1 cc.
These specifications could also be estimated
graphically from figures 1-4.

These specifications are based on seedlings
grown on a less droughty site than those typically
found in the mountains. However, the height
suggested by the analysis is at the low end and
the diameter is at the high end of the range of
specifications given for an initial target
seedling to be planted on Ouachita and Ozark
Mountain sites (Barnett and others 1987).
Therefore, we think that the root volume suggested
by this analysis is an appropriate addition to
those target specifications. Note that 3.1 cc is
the target root volume, the minimum acceptable
would be somewhat less and would depend on what
was defined as a minimum performance level.

SUMMARY AND RECOMMENDATIONS

This study was designed to evaluate the
effect of nursery bed density on the morphology
and subsequent field performance of shortleaf pine
seedlings. Because seedling morphology is so
strongly related to seedbed density, it was not
possible to separate the effects of density and
morphology on field performance in this study.
However, based on the above results and discussion
the following recommendations are made:

1) To produce shortleaf pine seedlings with
the morphological characteristics for rapid
first-year growth in the field, nursery bed
density should be kept below 235/m .

2) For any species, root volume should be
included in the development of target seedling
specifications. While not as easy to measure as
shoot length or diameter, root volume
determination is not excessively difficult nor
time consuming.

3) Because density can influence seedling
nutrient status, it should be remembered that the
effects of density on growth and performance are
confounded by the effects of fertilization.

LITERATURE CITED

Barnett, J. P.; Brissette, J.C.; Carlson, W.C.

1987. Artificial regeneration of shortleaf
pine. IN: Murphy, P. A., ed . Proceedings of
Symposium on the Shortleaf Pine Ecosystem;
1986 FMarch 31-April 2; Little Rock, AR.
Monticello, AR: Arkansas Cooperative
Extension Service; 64-88.

Brissette, J.C. 1985. Summary of discussions
about seedling quality. In: Lantz, C.W.,
ed. Proceedings 1984 Southern Nursery
Conference; 1984 June 11-14; Alexandria, LA;
and July 24-27; Asheville, NC. Atlanta, GA:
U.S. Department of Agriculture, Forest
Service, Southern Region; 127-128.

Brissette, J.C; Carlson, W.C. 1987. Effects of
nursery bed density and fertilization on the
morphology, nutrient status, and root growth
potential of shortleaf pine seedlings. In:
Phillips, D.R. , ed. Proceedings of the Fourth
Conference: 1986 November 4-6; Atlanta, GA.
Asheville, NC: Gen. Tech. Rpt. SE-42; U.S.
Department of Agriculture, Forest Service,
Southeastern Forest Experiment Station;
198-205.

Burdett, A.N. 1979. A nondestructive method for
measuring the volume of intact plant parts.

Canadian Journal of Forest Research.
9:120-122.

Carlson, W.C. 1986. Root system considerations in
the quality of loblolly pine seedlings.
Southern Journal of Applied Forestry.
10:87-92.

Chapman, A.G. 1948. Survival and growth of

various grades of shortleaf pine planting
stock. Iowa State College Journal of
Science. 22: 323-331.

Clark, F.B.; Phares, R.E. 1961. Graded stock
means greater yields for shortleaf pine.
Tech. Pap. 181. Columbus, OH: U.S.
Department of Agriculture, Forest Service,
Central States Forest Experiment Station; 5 p

Harms, W.K.; Langdon, O.G. 1977.

Competition-density effects in a loblolly
pine seedling stand. Res. Pap. SE-161.
Asheville, NC: U.S. Department of Agriculture
Forest Service, Southeastern Forest Experiment
Station: 8 p.

Kitchens, R.N. 1987. Trends in shortleaf pine
tree improvement. In: Murphy, P. A., ed.
Proceedings of Symposium on the Shortleaf Pine
Ecosystem; 1986 March 31-April 2; Little Rock,
AR. Monticello, AR: Arkansas Cooperative
Extension Service; 89-100.

Mexal, J.G. 1981. Seedling bed density influences
seedling yield and performance. In: Lantz,
C.W., ed. Proceedings 1980 Southern Nursery
Conference; 1980 September 2-4; Lake Barkley,
KY. Tech. Pub. SA-TP17. Atlanta, GA: U.S.
Department of Agriculture, Forest Service,
Southeastern Area State and Private Forestry;
89-95.

Shoulders, E. 1961. Effect of nursery bed density
on loblolly and slash pine seedlings. Journal
of Forestry 59:576-579.

Wakeley, P.C. 1954. Planting the southern pines.
Agriculture Monograph 18. U.S. Department of
Agriculture; 233 p.

Polymeric Nursery Bed Stabilization to Reduce Seed
Losses in Forest Nurseries^

William C. Carlson, John G. Anthony, and R. P. Plyler^

Abstract: A nolymerization treatment usinq Geotech, a
cooolymer of acrylate and vinyl acetate monomers, was used to
stabilize forest nursery beds to substantially reduce wind
and water erosion. Such treatment did not affect either the
temperature of the seed zone in the soil or germinant emer-
gence. Seed losses were reduced by the treatment, resulting
in increased nursery yield.

^ This article apoeared in full in the Southern
Journal of Apolied Forestry, 11(2) : 116-119, 1987.

2 William C. Carlson and John G. Anthony are with
the Southern Forestry Research Center, Weyerhaeuser
Company, Hot Sorings, Arkansas. R. P. Plyler is
with Weyerhaeuser Comoany's Magnolia Forest
Regeneration Center, Magnolia, Arkansas.

Improving Outplanting Survival of Stored Southern
Pine Seedlings by Addition of Benomyl
to the Packing IViedium^

James P. Barnett and John C. Brissette^

Abstract . — Field survival of longleaf, shortleaf , slash, and
loblolly pine seedlings planted with benomyl incorporated in the
packing medium was markedly improved over that of controls with
clay-slurry packing medium. Longleaf pine (_Pinu8 palustri 3 Hill.)
and shortleaf pine (P. elliottii Englem.) seedlings, which are more
difficult to store, had greater magnitudes of response than the more
easily stored loblolly and slash pine seedlings.

INTRODUCTIOM

Clay-benomyl (Benlate®)-^ mixture used as a
root dip treatment at the time of planting provi-
des systemic protection of longleaf pine (.Pinus
palustris Mill.) seedlings from brown-spot disease
(Sairrhia aoiaola (Dearn.) Siggers). Protection
should last for at least one year in the field
(Kais and Barnett 198A; Cordell et al. 1984; Kais
et al. 1986a, 1986b). This treatment has resulted
in improved survival and early height growth (Kais
1985; Kais and Barnett 198A; Kais et al. 1986b).
Benomyl is a very effective fungicide that is
recommended for a number of other uses in con-
tainer and bare-root nursery seedling production
(Barnett and Brissette 1986; Sutherland 1984). It
also has the advantage of having no phytotoxic
effect on mycorrhizal development; in fact,
seedling development is enhanced by benomyl use
(Pawuk and Barnett 1981).

Recent tests have shown that longleaf pine
seedling storage may be dramatically improved by
the incorporation of benomyl into the clay slurry
used for seedling packing (Barnett and Kais 1987).
Early results have stimulated additional testing
and extension of the technique to other species.

^Paper presented at the Intermountain Nursery
Association Meeting, Oklahoma City, Oklahoma, August
10-14. 1987.

^Principal silviculturist and silviculturist ,
respectively, USDA-Forest Service, Southern Forest
Experiment Station, Pineville, LA 71360.

■^Mention of trade names is for information
only and does not constitute endorsement by the
USDA Forest Service.

METHODS

Three studies are underway by the Southern
Forest Experiment Station to evaluate the effect
of fungicides on storage of southern pine
seedlings. In study 1, longleaf pine seedlings
from a single seed lot were lifted in January 1985
from beds at the Ashe Nursery in Mississippi.
Seedlings were divided into two sublots for two
storage periods (1 and 3 weeks), and five root
packing material treatments were applied for each
storage period: (1) clay slurry control, (2) clay
slurry, with a benomyl dip added at the time of
planting, (3) clay slurry with benomyl added at
the time of packing, (4) peat moss control, and
(5) peat moss combined with a benomyl dip treat-
ment. Benomyl was applied as a lO-percent mixture
of Benlate® VJP50 with kaollnate clay. This
resulted in an approximate 5-percent a.i, of beno-
myl in the clay slurry or dip. A lO-percent dilu-
tion of benomyl in water was used as a dip prior
to packing with peat moss for treatment 5.

In study 2, longleaf pine, loblolly pine (P.
taeda L. ), and shortleaf pine (P. eohinata Hill .)
seedlings from the Ashe Nursery were lifted in
January 1986 and divided into three sublots for
three storage periods (0, 3, and 6 weeks). Two
root packing treatments were applied to each of the
three sublots: (1) clay slurry control and (2)
10-percent Benlate® WP50 and clay slurry mixture.

In study 3, two seedlots (Florida and
Mississippi) of slash pine (P. elliotti Engelm.)
and three (Alabama, Louisiana, and north
Mississippi) of loblolly pine were lifted at the
Ashe Nursery late in the season (March 9, 1987)
and subdivided for two treatments (0 and 6 weeks)
The dosage rate was reduced to one-fourth the rate
of the earlier test, i.e., a 2.5-percent mixture
of Benlate® WP50 and kaolinate clay. The control
was a clay slurry.

In all tests, seedlings were packed in Kraft
polyethylene bags (350 per bag) and stored at
35°F. Seedlings of the 0 week treatment were
planted within 3 or 4 days, while the other
plantings were made after 3 or 6 weeks of storage.
Seedlings were machine planted at 5- by 5-foot
spacings in 2 rows of 50 seedlings; there were 4
replications. Study 1 was outplanted on two
different sites in central Louisiana. Only one site
was used for the other two studies. Seedling
survival was measured in June and December of the
same year following planting. Study 1 was also
measured for survival and height after 2 years in
the field.

Differences in survival were tested for
significance at the 0.05 level by analyses of
variance. Duncan's Multiple Range Test was used
to evaluate treatment means.

RESULTS

Study 1. — The outplanting site had a
considerable influence on longleaf pine seedling
survival after two growing seasons. Heavier grass
and woody competition as well as greater brown-
spot incidence occurred on site 1. Nevertheless,
treatment effects followed the same trends on both
sites. Both length of seedling storage and
packing-medium treatments significantly affected
seedling performance. Survival of seedlings that
had undergone 3 weeks of storage was markedly
lower than for the 1-week storage period (fig. 1).
The effect of storage varied greatly depending on
packing-medium treatments, and for both sites
there was a storage X packing treatment interac-
tion.

] 1 week V///A 3 weeks

for the 3-week storage treatment. The clay-slurry
treatments averaged 19, 33, and 79 percent sur-
vival for the control, benomyl dip at planting,
and the clay-benomyl slurry, respectively. The
peat moss control averaged 64 percent, three times
that of the clay-slurry control. The addition of
benomyl to the peat moss treatment improved sur-
vival by 13 percentage points.

Study 2. — Longleaf, loblolly, and shortleaf
pine seedlings receiving clay-slurry control and
clay-benomyl treatments were planted after storage
periods of 0, 3, and 6 weeks. Response after 1
year varied by species. Longleaf pine seedlings
had the lowest survival regardless of treatment,
and benomyl improved survival after all lengths of
storage (fig. 2). In contrast, survival of
loblolly pine seedlings was almost 100 percent
regardless of treatment or storage. Survival of
shortleaf pine seedlings without storage (0-week
storage period) averaged 99 percent, but after
being stored for 3 and 6 weeks, survival of the
controls dropped to 83 and 36 percent, respec-
tively. Benomyl-treated shortleaf seedlings main-
tained the same level of survival even after
storage (fig. 2).

Study 3. — The loblolly and slash pine
seedlings lifted later in the season (March 9)
were planted within 1 week (0-week storage period)
and after 6 weeks. These seedlings were treated
with the clay slurry and a clay-benomyl slurry at
one-fourth the rate used in the slurries of the
other studies. After 3 months in the field, there
were marked differences between packing treat-
ments. Loblolly pines stored 6 weeks averaged 23
and 87 percent, respectively, for the clay and
clay-benomyl treatments (fig. 3). Comparative
treatments for slash pine averaged 9- and
88-percent survival.

Clay
slurry

Clay-benomyl Clay-benomyl Peat moss
dip slurry

Peat with
benomyl
dip

Figure 1. — Survival of longleaf pine seedlings
stored 1 and 3 weeks with various root
packings 2 years after outplanting (Study 1.)

The clay-slurry and peat moss controls had
consistently lower survival than any of the beno-
myl treatments when stored 1 week (fig. 1). The
magnitude of treatment difference was much greater

Longleaf pine

■benotnyl

Loblolly pine

Shortleaf pine

Figure 2. — Survival of longleaf, loblolly, and

shortleaf pine seedlings stored for 0, 3, and
6 weeks with two root packings 1 year after
outplanting (Study 2). Numerals above bars
represent number of weeks stored.

] CUy V///A CUy-benonyl

■3

100
M
80
70
80
50
40

20
10
0

!
1,

Loblolly pine Slash pine

Figure 3. — Survival of loblolly and slash pine

seedlings stored for 0 and 6 weeks with two
root packings 3 months after outplanting (Study
3). Numerals above bars represent number of
weeks stored.

DISCUSSION

Results of all three tests showed a very
positive response from the incorporation o* beno-
myl into the clay slurry used for seedling
packing. The root dip in benomyl followed by
seedling storage in peat moss followed the same
trend. Preliminary pathological evaluations indi-
cate that benomyl is controlling pathogenic
microorganisms that reduce seedling quality after
storage of 3 or 6 weeks. Survival of longleaf
pine seedlings, which are the most difficult of
the southern pines to store, is improved by beno-
myl treatment even when the seedlings are
outplanted within 1 week. The second greatest
response was with shortleaf pine. Major improve-
ments in shortleaf pine survival occurred with 3
to 6 weeks of storage.

Loblolly pine seedlings lifted in early
January survived well without benomyl treatment.
However, when loblolly and slash seedlings were
lifted in March and stored for 6 weeks, seedlings
that received benomyl treatment were able to be
stored satisfactorily. Those without such treat-
ment showed a large decrease in survival.
Additional studies are underway to evaluate the
mechanisms involved in deterioration of seedlings
during storage; other studies are underway to
determine the effect of date of lifting on
seedling storage.

LITEEIATURE CITED

Barnett, James P.; Brissette, John C. 1986.

Producing southern pine seedlings in con-

tainers. Gen. Tech. Report SO-59. New
Orleans, LA: U.S. Department of Agriculture,
Forest Service, Southern Forest Experiment
Station. 71 p.

Barnett, James P.; Kais, Albert G. 1987.

Longleaf pine seedling storability and
resistance to brown-spot disease improved by
adding benomyl to the packing medium. In:
Proc. Fourth biennial Southern Silvicultural
Research Conference, November 4-6, 1986,
Atlanta, GA. Gen. Tech. Report SE-24.
Asheville, NC: U.S. Department of
Agriculture, Forest Service, Southeastern
Forest Experiment Station. P. 222-224.

Cordell, C. E.; Kais, A. G.; Barnett, J. P.;

Affeltranger C. E., 1984. Effects of benomyl
root storage treatments on longleaf pine
seedling survival and brown-spot disease
incidence. In: Proc. 1984 Southern Nursery
Conference. Western Session: Alexandria,
LA, June 11-14. Eastern Session:
Asheville, NC, July 24-27, 1984. U.S.
Forest Service, Southern Region, Atlanta,
GA. p. 84-88.

Kais, A. G. 1985. Recent advances in control of
brown spot in longleaf pine. Proc. 34th
Annual Forestry Symposium, March 26-27,
1985. Louisiana State Univ.: 83-90.

Kais, A. G.; Barnett, J. P. 1984. Longleaf pine
grown following storage and benomyl root-dip
treatment. Tree Planters' Notes 35(l):30-3'

Kais, A. G.; Cordell, C. E.; Affeltranger, C. E.
1986a. Benomyl root treatment controls
brown-spot disease on longleaf pine in the
Southern United States. Forest Science
32:506-511.

Kais, A. G.; Cordell, E.; Affeltranger, C. E.
1986b. Nursery application of benomyl
fungicide for field control of brown-spot
needle blight ( Sairrhia aoicola (Dearn.)
Siggers.) on longleaf pine ( Pinus palustris
Mill.). Tree Planters' Notes 37(1):5.

Pawuk, William H. ; Barnett, James P. 1981.

Benomyl stimulates ectomycorrhizal development
by Pisolithua tinatorius on shortleaf pine
grown in containers. Res. Note SO-267. New
Orleans, LA: U.S. Department of Agriculture,
Forest Service, Southern Forest Experiment
Station. 3 p.

Sutherland, J. R. 1984. Pest management in

Northwest bareroot nurseries. Chapter 19 in
Forest Nursery Manual: Production of
Bareroot Seedlings. Duryea, Mary R.;
Landis, Thomas D.; editors. Martinus
Nijhoff/Dr. W. Junk Publishers, The Hague,
p. 203-210.

Measuring Tree Seed Moisture Content Now
and in the Future

Robert P. Karrfalt^

Abstract. — The procedure used in developing conversion
charts for tree seed for use with a relatively inexpensive
electronic seed moisture tester is given. A list of the
species for vrtiich charts have been made is given, A brief
discussion is presented on the potential future uses of regu-
lating seed moisture.

INTRODUCTION

The regulation of seed moisture is critical to the
management of high quality seed . Mechanical
injury or high temperatures can have detrimental
effects to be sure, but the moisture content of
seeds no doubt is the most influential of all the
factors that can effect the quality of seeds
(Justice and Bass, 1979). The date of harvest of
cones, fruits, or seeds is generally related to
moisture content. Conifer cones must be air dried
to a specified range of moisture content in order
to produce maximum yields and highest quality
seed. Kiln drying of cones that are too high in
moisture content will result in case hardening of
the cone and a poor seed yield. Most temperate
zone species that have moisture contents below 10
percent can be stored at cold temperature for
years while seed at high moisture content will
live only a few months even with ideal
temperatures. These are but a few brief
examples of how critical the regulation of seed
moisture is to the quality of seed.

ROUTINE SEED STORAGE

For routine seed storage the seed handler is
concerned with maintaining seed basically at a
threshold moisture level. For the vast majority
of temperate species this threshold value is 10$
on a wet weight basis. Extremely low values of 2
or 3% might lead to seed damage according to some
reports, but data (Justice and Bass, 1979, Benson,
1970) exists that shows that this is probably not
the case. The examples of loss of viability due
to low moisture content are probably explainable
as imbibitional injury when planted. A slow
uptake of water would allow those seeds with ultra
low moisture contents to maintain a high level of
viability.

Director, National Tree Seed Laboratory,
USDA Forest Service, Dry Branch, Georgia.

A desirable test for moisture is one that is
fast, inexpensive, and gives acceptable accuracy.
There are a number of electronic moisture testers
available that will give quick results. However,
they generally cost about $1,000 or more. For the
small forestry operation this might represent a
substantial portion of the annual budget for
equipment. So for many the $1000 meter may not be
inexpensive. Also none of the meter manufacturers
concern themselves with forestry and conservation
seeds in the calibration of their meters.
Therefore, the meter will not be useable until
someone conducts the necessary measurements to
relate meter readings to actual seed moisture
contents.

For many years a small meter was available for
which the National Tree Seed Laboratory had
developed conversion charts. This was the PB-71
made by the Eaton Corporation. It was marketed
under a number of names: Dole, Radson, Burrows,
and Gilmore-Tatge . Unfortunately this meter was
improved for the tester of grains, and tree and
shrub seed testers could no longer use it. The
electronic parts were modified such that they no
longer functioned in the range needed for woody
plant seed. To quickly replace this naich needed
meter, an effort was made in cooperation between
the National Tree Seed Laboratory and many private
and public agencies to develop conversion charts
for another. relatively inexpensive meter, the
Dickey- john grain moisture tester for corn. The
following have donated seed for this work: R. W.
McPhearson, California Division of Forestry,
Michigan Department of Natural Resources, Dean
Swift Seed Company, Louisiana Forest Seed Company,
W.W. Ashe Nursery, J. Herbert Stone Nursery, J.W.
Toumey Nursery. The effort to develop charts is
still going on, and the NTSL will be happy to
develop a chart as soon as possible if your
desired species are not on the charts.

Use of trade or firm names in this publication
is for reader information and does not imply
endorsement by the U.S. Department of Agriculture
of any product or service.

DEVELOPMENT OF THE CONVERSION CHARTS

The procedure followed in developing the
moisture charts for the Dickey- John meter was
based on the following reasoning. 1. The
variation in meter readings among samples from the
same seed lot and among seed lots at any given
moisture content would be small (less thain one
percent moisture). If variation was large then
the meter would not be useful because multiple
readings would be required, and the meter would
not be a quick test. 2. It follows from the first
statement that the samples tested in the meter
could all come from one seed lot if that seed lot
was at all representative. 3. The concern in
storing tree seed is that the moisture content be
below a given threshold value. Therefore, vrtiether
the true moisture is 5, 6 or 8? is not important.
What is important is that we are certain that the
value is below the critical threshold . Our
primary concern in developing these charts was,
therefore, not necessarily to have a high degree
of precision but to have numbers that will tell us
that we have our seed dry enough for long term
storage .

The first step in developing the charts was
the selection of a seed lot that was of good
average germination and purity for the species.
This seed lot was then soaked overnight in water
to fully imbibe the seed . The water was drained
off, and the seed was placed on the seed drier.
As soon as the seed was surface dry, a reading was
taken on the meter and in the drying oven. The
drying oven moisture determination was done on
duplicate 5 gram samples at 103 C + 2 C for 17
hours + 1 hour (International Seed Testing .
Association, 1985). Generally the moisture
content was in the neighborhood of 20 to 25% on
the first reading. Subsequent readings were taken
every one to two hours depending on how fast the
drying was taking place. Readings were taken
until the seed reached moisture contents of 4 to
6%. In some cases the end moisture content
achieved was only 7 or 8$. Some of the species
tested had a conversion chart developed for the
PB-71 meter. Readings from the PB-71 served as a
check that the seed lot being used was
representative of the species. The reasoning on
that point was this. If the reading from the
PB-71 was within tolerance with the oven reading,
then there was confidence that the seed lot being
used was representative. In all cases the
readings were within tolerance so that the
procedure of using one seed lot seems valid.

The second step was the regression of the
meter readings on the moisture contents determined
by the oven procedure. This regression produced a
prediction equation for calulating the meter
readings from oven measurements. Using oven
measurement values from 6 to 18$ in steps of 0.5%
a set of meter readings was computed from the
prediction equation. The computed values are the

conversion chart values. The measurements made
with the Dickey- John meter on several loblolly
pine seed lots agree with the readings found by
the oven, and show that the procedure is
appropriate .

Conversion charts have been made for the
following species:

WESTERN SPECIES

Abies concolor
Abies grandis
Abies magnifica
Calocedrus decurrens
Picea engelmannii
Picea sitchensis
Pinus contorta
Pinus coulteri
Pinus .jefferyi
Pinus lambertiana
Pinus muricata
Pinus ponderosa
Pinus radiata
Pseudotsuga menziesii

NORTHERN SPECIES

Betula paperifera
Betula allegheniensis
Larix laricina
Picea abies
Picea glauca
Picea mariana
Pinus banksiana
Pinus resinosa
Pinus strobus
Thu.ia plicata
Tsuga canadensis
Crataegus phaenopyrum

SOUTHERN SPECIES

Pinus

clausa

Pinus

elliottii

Pinus

palustris

Pinus

taeda

Pinus

virginiana

Persons needing the charts may obtain them
from the National Tree Seed Laboratory, Rt. 1, Box
182B, Dry Branch, GA 31020.

REGULATION OF SEED MOISTURE CONTENT IN THE FUTURE

To this point we have talked about regulating
seed moisture as a very basic technology. We
wanted only to maintain our seed below a given
threshold of moisture so that we could safely have
long term storage of seed. This is an extremely
important aspect of seed moisture that will stay
with us for as long as we store seed in the manner
we currently do.

During the last 10 years, however, the
literature has had some articles on regulating
moisture content of stratified seed that allows
the nursery manager to store seed while either
maintaining the benefits of stratification or even
enhancing the benefits of stratification.
Danielson and Tanaka (1978) found that by air
drying stratified seed of Douglas fir and
ponderosa pine that the seed could be stored for
up to 9 months without reinstating dormancy or
causing deterioration of the seed. Belcher (1982)
confirmed the findings of Danielson and Tanaka
with Douglas fir and found the same to be true for
loblolly pine. De Matos Malavasi et. al. (1985)
showed that seedlings produced from air dried
Douglas fir seed were larger at age 5 days than
seedlings from seed which were stratified only.
Numerous studies on improving the vigor of seeds
by priming with PEG have been reported in the
literature. It seems quite likely that the
improvement in vigor might come from an effect
brought on by the PEG regulating the moisture
content of the seed. It is also well established
that the moisture content of the seed and its
various constituent parts has a profound control
over the condition of the cell membranes and the
metabolic and chemical activities that occur
within the seed (Priestly, 1986).

In the future it is very likely that seed
handlers will want to regulate the seed moisture
for purposes of regulating the effects of the
presowing treatments. Today's forms of
stratification could well be replaced with more
sophisticated procedures. To do this we will want
to measure moisture in ranges between 20% and 30$
or H0%. A type of meter like the Dickey- John will
allow for quick measurements in this range.
Therefore, as the seed physiologists discover the
critical moisture contents to regulate seed

performance, the technology exists to adapt this
new information for practical application by the
nursery manager.

LITERATURE CITED

Belcher, E.W. 1982. Storing stratified seeds for
extended periods. Tree Planter's Notes
33(4): 23-25.

Benson, Darrell A. 1970. Sixteenth Annual Report,
Eastern Tree Seed Laboratory, USDA Forest Ser
vice. pg. 6.

De Matos Malavasi, Marlene, Susan G. Stafford, and
D.P. Lavender. 1985. Stratifying, partially
redrying and storing Douglas-fir seeds:
effects on growth and physiology during ger-
mination. Ann. Sci. For. 42(4 ) :371-384.

Danielson, H. Rodger, Yasuomi Tanaka. 1978. Drying
and storing stratified ponderosa pine and
Douglas-fir seeds. Forest Science
24(1):11-6.

International Seed Testing Association. 1985. In-
ternational Rules for Seed Testing 1985. Seed
Science and Technology 13(2): p. 338 - 341.

Justice, Oren L. and Louis N. Bass. 1978. Prin-
ciples and practice of seed storage. U.S.
Department of Agriculture Handbook No. 506.
289 p.

Priestly, David A. 1986. Seed Aging, Implications
for Seed Storage and Persistence in the Soil.
304 p. Comstock Publishing Associates,
Ithaca, NY.

Forest Tree Nursery Herbicide Studies at the Olclahoma
Forest Regeneration Center^

Lawrence P. Abrahamson^

Abstract. — Eight herbicides (registered for similar uses in
the U.S.) were extensively evaluated at the Forest
Regeneration Center, Oklahoma Forestry Division, Washington,
Oklahoma, for weed control on first year seedling nursery
beds. Phytotoxicity evaluations of dcpa, napropamide,
oxyfluorfen, diphenamid, bifenox. oxadiazon, trifluralin and
prometryn on 19 different conifer and hardwood species are
presented.

Additional key words: Enide®, Treflan®, Dacthal®, Caparol®,
Devrinol®. Modown®, Goal®, and Ronstar®.

INTRODUCTION

The USDA Forest Service developed a number of
nursery herbicide projects in the United States out
of a recognition of the potential benefits of
herbicidal control of weeds in nursery seedbeds.
This paper will concentrate on projects conducted
at the Forest Regeneration Center, Oklahoma
Forestry Division, Washington, Oklahoma. The
Oklahoma tree nursery was part of the following
projects. The cooperative v;estern nursery
herbicide project, initiated in 1976, with
cooperation among state, private and federal
nurseries. Forest Service Research, State and
Private Forestry. National Forest Systems, and
State University of New York out of Syracuse.
Twenty-eight nurseries in 12 states were involved
in this effort which was broken down into three
segments, each of three-year duration; the Pacific
Coast started in 1976 (Stewart 1977. Owston et al .
1980. Owston and Abrahamson 1984). the
Intermountain-Great Basin in 1977 (Ryker and
Abrahamson 1980), and the Great Plains in 1978
(Abrahamson 1981, Abrahamson and Burns 1979) which
the Oklahoma Nursery was a part of. In 1979 the
Northeastern (NE) Area started an eastern nursery
herbicide project in five states cooperating with
Purdue University and State University of New York
(SUNY) at Syracuse (Holt and Abrahamson 1980). In
1981 the NE Area expanded the eastern nursery
herbicide project to the Great Lakes area with
eight nurseries (state, federal and private) in

^Paper presented at the Intermountain Forest
Nursery Association 1987 Annual Meeting. (Park
Suite Hotel, Oklahoma City, OK, August 10-14, 1987.

^Lawrence P. Abrahamson is a Senior Research
Associate, State University of New York College of
Environmental Science and Forestry, Syracuse, NY.

three Lake States cooperating with SUNY (Abrahamson
and Jares 1984).

During 1982, after the Great Plains segment of
the cooperative western nursery herbicide project
was completed, Oklahoma State (Abrahamson 1983)
sponsored a nursery herbicide project of their own
in cooperation with SUNY to help the nursery expand
on the herbicide studies using different
herbicides, tree species and sowing times. This
study has continued on a yearly basis through 1987-
88.

What is important in these projects is that
all studies have similar objectives and
methodologies and that information developed from
one region or study project is supportive of that
from other regions. In all these studies the
objectives were to identify promising herbicides,
develop data for product registration, and
demonstrate safe and effective weed control
practices for nursery seed beds.

METHODS

The nursery herbicide screening and
demonstration projects were initiated as part of a
three-year study. During the first year of the
three-year study up to ten herbicides (eight of
which are represented in Table 1) were screened on
two to four major species of spring- and/or fall-
sown conifers and/or hardwoods depending on the
year involved in the study.

Treatments were applied to three- or six-foot
long plots in four-foot wide nursery beds with a
one-foot untreated buffer between plots. All
treatments were installed in a randomized block
design with three replications per species.
Herbicides were applied with a modified Hudson®

Table 1. Herbicides, rates, and application timings used in the Nursery Herbicide Studies
Conducted by SUNY at the Oklahoma Forest Regeneration Center.

Appl icat ion Timing

Herbicide Formulation Manufacturer (lb ai/A) Inc^ or Ps^ Pg^ Ps + Pg''

Diphenamid

Enide SOW; 90 W

Nor-Am

4.0

Trif luralin

Treflan 4EC

Elanco

0.75

DCPA

Dacthal W-75

SBS Biotech

10.5

Prometryn

Caparol SOW

C iba-Geigy

1.0

Napropamide

Devrinol SOW

Stauf fer

1.5/3.0

Bi f enox

Mowdown SOW; 4F

Rhone-Poulenc

3.0

Oxyf luor f en

Goal 2E; 1.6E

Rhom & Haas

0.5

Oxadiazon

Ronstar G

Rhone-Poulenc

1.0

Napropamide

Tank Mix

1.0+3.0

& Bifenox

Pre-seeding incorporation: incorporated into top 2 inches of soil immediately before seeding.
Post-seeding: broadcast applied to soil immediately after seeding.
Post-germination: broadcast applied to soil 4 to 5 weeks after seedling emergence.
Post-seeding plus post-germination: two separate applications at the full recommended rate.

type pressure hand sprayer, or a modified AZ plot
pressurized sprayer equipped with check valves and
four flat fan 8001 nozzles operated at 20 psi in a
water carrier at a volume equivalent to 85 ppa (100
ml/three-foot plot). Granular formulations were
ocularly applied from a hand shaker uniformly over
the plot.

Pre-seeding incorporated treatments were
applied no more than one day before seeding and
incorporated into the top two inches of soil using
a garden rake. Post-seeding treatments (Ps) were
applied within two days after seeding, except on
the fall-sown species which were applied any time
after fall seeding but before mulching. Post-
germination treatments (Pg) were applied four to
six weeks after seedling emergence, except on the
fall-sown species which were applied in the spring
after seedlings had emerged.

Herbicidal damage to conifers/ hardwoods at
the end of the first growing season was evaluated
using a ten-point rating scale (0 is complete kill,
10 is no effect) proposed by Anderson (1963).
Height of nine randomly selected seedlings and
number of seedlings per foot in three randomly
selected rows in each plot were also measured to
determine chemical effects on germination, seedling
growth and survival.

The objectives of the second-year studies were
to evaluate the phytotoxici ty and weed control
effectiveness of three to four herbicides screened
from the first-year study to be non-phytotoxic to
the species tested and have reasonable weed control
of weeds present at that nursery. Phytotoxicity
was evaluated by using herbicidal damage ratings
(Anderson 1963), seedling survival (number/foot)
and height growth (cm). Dosages of IX, 2X, and IX

+ IX of these herbicides were applied post-seeding
and/or post-germination using three- or six-foot
long plots in four-foot wide beds with a one-foot
untreated buffer between plots. All treatments
were installed using a randomized block design with
three replications per species. Herbicide
treatments were applied by small pressurized
sprayer or hand shaker as was done the first year
of these studies.

During the Great Plains part of the Oklahoma
studies, weed control effectiveness of the best
treatments were evaluated under operational use
using nursery application equipment on 100-foot
test plots. The herbicides were evaluated for weed
control under operational use at the IX rate of
application applied post-seeding along, or post-
seeding and post-germination. Phytotoxicity
rating, survival and height measurements were also
recorded from these operational plots.

RESULTS AND DISCUSSION

Earlier results from the Oklahoma nursery
studies has been reported in a similar manner
(Abrahamson 1984, 1986). Phytotoxicity data from
all Oklahoma studies through 1987 is presented in
Tables 2-12, listed by herbicides tested under each
species. The tables are summaries of all the
phytotoxicity studies and indicate; 1) those fall-
and/or spring-sown seedlings where the herbicide
has been safely applied at rates indicated without
stunting or germination reduction (x); 2)
herbicides that appear to be promising at rates
indicated, but because of possible phytotoxic
problems implied in some of our studies, these
should be thoroughly tested before using at your
nursery (o); 3) herbicides that should not be used

at rates indicated because of severe phytotoxic
damage (-). One herbicide that should be
elaborated on is napropamide. Napropamide is used
at the lower rate (1.5 lbs ai per acre) when the
nursery soil has below 1 percent organic matter,
otherwise the higher rate (3.0 lbs ai per acre) is
normally used. Napropamide is safe to use post-
seeding on most spring-sown conifer species tested,
but caused severe stunting when applied post-
seeding to fall-sown conifer species in the Lake
States study. Napropamide applied post-germination
to both spring- and fall-sown conifers caused no
phytotoxic problems.

Weed control expressed in terms of hand-
weeding time, or "how much time can herbicides save
you versus hand-weeding" is one of the most
important aspects of these studies. In the Great
Plains study (Abrahamson 1981) on spring-sown
species the post-seeding applications were as
effective as the post-seeding plus post-germination
applications for total season weed control. The
Forest Regeneration Center in Oklahoma is an
example (Abrahamson 1983) of the type of savings in
time and money that can be expected from these
herbicides when used in forest tree nurseries.

Hand weeding time at the Oklahoma Forest
Regeneration Center during 1981 was reduced by an
average of 80 percent for all herbicides applied
only in the spring (Ps) while those applied in both
the spring and a second application five to six
weeks later (Ps + Pg) reduced hand weeding time by
an average of 87 percent. Based on minimum wage of
$3.35 per hour, this would amount to an average
gross saving of $4,600 per acre of seedbed (without
figuring in cost of herbicide or application costs)
weeded six times with a mean weeding time of 283
man hours per acre untreated seedbeds at Norman
(Abrahamson 1983).

SUMMARY

There have been numerous trials, studies and
tests of various herbicides at many different
nurseries that have demonstrated the safe and
effective use of dcpa, napropamide, oxyfluorfen,
diphenamid, bifenox, oxadiazon, trifluralin, and
prometryn on various conifer and/or hardwood first
year seedling nursery beds. These herbicides have
reduced the time required to hand-weed nursery beds
by 80-87 percent when applied at sowing time alone
or with a second application four to six weeks
later. Over $4 , 000-$7 , 000 per acre of seedbed
could be saved by using these herbicides over hand-
weeding alone.

However, the safety and effectiveness of any
herbicide should be tested at each nursery before
operational use. These herbicide trials are urged
because there is a strong possibility of
differential results from varied interactions of
different mixtures of tree and weed species, soil
and climatic factors, and cultural practices at
different nurseries. If a particular herbicide has
never been used at your nursery, several years of
trials are advisable because of variations in

effects caused by different weather conditions.
Trials should include "double doses" to evaluate
the safety limits on crop seedlings and leave an
untreated control to properly evaluate the effects
of the herbicide.

LITERATURE CITED

Abrahamson, L.P. 1981. Herbicide trials for weed
control in Great plains Forest tree nurseries.
In: Proceedings of the 33rd Annual Meeting of
the Forestry Committee, Great Plains Agr .
Council, June 1981, Lubbock, TX, Great Plains
Agr. Council Publ . #102; p. 65-102.

Abrahamson, L.P. 1983. Herbicides, an important
component of the weed control program at
Oklahoma State (Norman) Nursery. In:
Proceedings of the 1982 Southern Nurserymen's
Conf., Southern Region, U.S. Forest Service,
Technical Publ. R8-TP4, p. 171-191.

Abrahamson, L.P. 1984. Forest tree nursery

herbicide studies in the Northeastern United
States: Highlights of research results. In ;
Proceedings of the Workshop: Weed Control in
Tree Nurseries, July 17-18, 1984, PFRA Tree
Nursery, Indian Head, Saskatchewan.
Agriculture Canada, PFRA. p. 6-21.

Abrahamson, L.P. 1986. Forest tree nursery
herbicide studies in the Northern Great
Plains: Herbicide phy totoxici ty tables. In:
Proceedings: Intermountain Nurserymen's
Association Meeting. Eds.: Landis, T.P. and
S.W. Fischer: 1985 August 13-15; Fort Collins,
CO, U.S.D.A. Rocky Mountain Forest and Range
Experiment Station General Technical Report,
RM-125, pp. 58-67.

Abrahamson, L.P. and K.F. Burns. 1979. Herbicide
screening for weed control in western forest
tree nurseries - Great Plains Segment. AFRI ,
Syracuse, NY, Res. Report No. 41; 15 pp.

Abrahamson, L.P. and T. Jares. 1984. Forest tree
nursery herbicide studies in the Lake States
and New York: Highlights of research results.
In: Northeast Area Nursery Supervisors
Conference Proceedings, August 6-9, 1984,
Dover, Delaware, Sponsored by Delaware Forest
Service. 25 pp.

Anderson, W.H. 1963. A system for evaluating

effective weed control in forest nurseries.
Tree Planter's Notes ( Oct .): 19-23 .

Holt, H.A. and L.P. Abrahamson. 1980. Developing
weed control programs for forest nurseries in
central U.S. In: Abstracts - 1980 Meeting of
Weed Sci. Soc. of Amer., Feb. 5-7, 1980,
Toronto, Canada, p. 51.

Owston, P.W., R.E. Stewart, N.W. Callan, and L.P.
Abrahamson. 1980. Evaluation of herbicides
for weed control in Pacific Coast forest tree
nurseries. In: Abstracts - 1980 Meeting of

Weed Sci. Soc. of Amer., Feb. 5-7, 1980, Ryker, R.A. and L.P. Abrahamson. 1980. Western
Toronto, Canada, p. 51-52. forest nursery herbicides study, Rocky

Mountain-Great Basin Segment. In: Abstracts
Owston, P.U. and L.P. Abrahamson. 1984. Heed - 1980 Meeting of Weed Sci. Soc. of Amer.,

management in forest nurseries. In: Duryea, Feb. 5-7, 1980. Toronto, Canada, p. 52.

M.L. and T.D. Landis (eds.). Forest Nursery

Manual: Production of Bareroot Seedlings. Stewart, R.E. 1977. Herbicides for weed control
Martinus Nijhoff/Dr. W. Junk Publishers. The in western forest tree nurseries.

Hague/Boston/Lancaster for Forest Research Proceedings, Western Society of Weed Science,

Laboratory, Oregon State Univ., Corvallis. 30:78-79.
386 p. (p. 193-202).

TABLE 2: Phytotoxic effects of herbicides tested on first year
loblolly, shortleaf and Austrian pine nursery beds.

LOBLOLLY PINE

Herbicide

Spring

Fall

Post- 1

Post-

Post-Seeding

Sown

Seedinq |

Germination

St Germination

dcpa

napropamide

oxyf luorf en

diphenamid

bif enox

trif luralin

napropamide &

bif enox

SHORTLEAF PINE

Herbicide

Spring

Fall

Post- 1

Post-

Post-Seeding

Sown

Seedinq |

Germination

& Germination

napropamide * x

oxyfluorfen * x

bifenox * x
napropamide &

bifenox * x

AUSTRIAN PINE

Herbicide

Spring

Fall

Post-

Post-Seeding

Sown

Seeding

Germination

& Germination

dcpa

napropamide

oxyfluorfen

diphenamid

bifenox

trif luralin

napropamide &

bifenox

XXX
XXX
O X o

XXX
O X o

O X o

X = no phytotoxic effects at nurseries tested.

o = some phytotoxic effects at one or more nurseries where tested

requires additional trials before operational use.
- = severe phytotoxic effects, Do Not Use.

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Use of Sulfur to Correct Soil pH^

Donald H. Bickelhaupt^

Abstract. — The addition of 1780 Ibs/ac of sulfur plus 1780
Ibs/ac of sulfur as sulfuric acid resulted in a temporary
decrease in soil pH. Seedling quality variables of Norway spruce
were related to soil pH at time of sowing.

INTRODUCTION

The New York State Department of
Environmental Conservation's Saratoga
Tree Nursery, located at Saratoga
Springs, New York, currently produces
four to five million bareroot conifer
seedlings annually (Scholtes 1985). The
100 acre nursery is located on deep
loamy sand (80 to 90% sand with 5 to 10%
clay) . In the past 10 years the nursery
has experienced problems in producing
high quality seedlings of some species
in some sections of the nursery.
Problems encountered are poor seed
germination, early seedling survival and
many of the seedlings grown were stunted
and chlorotic (Plumley 1986).

Between 1973 and 1977, the problem
areas had received two to 12 inches of
composted horse manure, including barn
sweeping. This organic material was
applied to the sandy soil to improve
cation exchange, moisture holding
capacity, and the amount of available
nutrients. Laboratory analysis of
several samples of material applied in
1973 indicated that the pH of the
material was 8.16. Elemental analysis
indicated that the material was very
heterogeneous. Calcium and magnesium

■""Paper presented at the
Intermountain Forest Nursery
Association 1987 Annual Meeting. Park
Suite Hotel, Oklahoma City, OK. August
10-14, 1987.

^ Donald H. Bickelhaupt is a
Research Assistant, SUNY College of
Environmental Science and Forestry
Syracuse, New York 13210

concentrations averaged 3.6% and 1.7%,
respectively. The concentrations of
nitrogen, phosphorus and potassium were
0.8%, 0.2% and 0.7%, respectively. The
high pH, and high concentration of
calcium and magnesium were the results
of lime being sprinkled daily on the
floors of the stables to control the
odor of urine.

A single, six inch application of
composted horse manure in 1974, to one
section of the nursery, increased the
soil organic matter from 5.0% to 8.0%
during the three years following
application. The organic matter concen-
tration had returned to approximately
pre-treatment level by 1982. Soil pH
increased from 5.7 to 7.2 as a result of
the single, six inch application of
manure. Soil pH was 7.0 twelve years
after applying manure.

Soil pH above the recommended range
of 5.5 to 6.0 is a concern for nursery
managers because of potential problems
with damping-off and nutrient imbalance.
Damping-off is favored in cool and wet,
neutral to basic soils containing large
amounts of organic matter (Manion
1981). Nutrients, such as potassium and
ammonium, become fixed in soils with a
high pH and are, therefore, unavailable
to plants. However, phosphorus
availability is greatest when soil pH is
between 6.0 and 7.0. Solubility of
micronutrients increases with acidity
and become toxic when soil pH is too low
(Tinus 1980) . Therefore, soil pH should
be maintained within the range where
nutrients are available for plant growth
but the micronutrients are not at toxic
levels .

Some conifer species are intolerant
to soil pH above 6.0. Mean total dry

weight of red pine (Pinus resinosa Ait.
has been shown to decrease as soil pH
increased from 5.4 to 7.8 (Armson and
Sadreika 1979) . The weight of shoots
and roots of greenhouse grown Douglas
fir (Pseudotsuqa menziesii (Mirb.)
Franco) , was greatest when soil pH was
5.5 (van den Driessche 1979) . Height
growth of Norway spruce (Picea abies
(L.) Karst . ) has been shown to be
related to soil pH with the tallest
seedlings being produced in soil with a
pH of 4.5 (Benzian 1965). Soil pH must
be maintained within the recommended
range of the species to produce an
adequate number of high quality
seedlings per unit area.

Sulfuric acid has been shown to be
more effective than granular sulfur in
reducing soil pH but the results are not
permanent (van den Driessche 1969) . In
contrast, sulfur reacts slowly with the
soil to reduce soil pH but the change is
considered permanent (Tinus 1980) .
Utilizing this information, a study was
established in the problem areas at the
Saratoga Tree Nursery in an attempt to
reduce soil pH and improve seedling
quality. The application of a combina-
tion of sulfuric acid and granular
sulfur was considered as a possible
method to quickly reduce soil pH and
maintain the soil pH between 5.5 and
6.0.

Use of Sulfur to Reduce Soil pH

METHODS

The amount of sulfur required to
reduce soil pH to a certain value varies
with initial pH and the amount of col-
loidal material in the soil. In
general, an application of 500 Ibs/ac of
granular sulfur is expected to decrease
soil pH by 0.5 units in the surface six
inches of sandy nursery soils (White et
al. 1980). To change soil pH from 7.5
to 6.5, the Western Fertilizer Handbook
(1980) recommends the addition of 500,
800 and 1000 Ibs/ac of sulfur to a
sandy, loam and clay soil, respectively.
Stoeckeler and Arneman (1960) suggested
that 870 Ibs/ac of sulfur would be
needed to lower the pH of a silt loam
soil from 7.0 to 6.0 and 1525 Ibs/ac of
sulfur would be required to lower the
soil pH from 7.0 to 5.5. To prevent
detrimental effects to seedlings, the
application of sulfur to a sandy nursery
soil should not exceed 750 Ibs/ac
(Armson and Sadreika 1979) .

Study plots had received a single
six inch application of composted horse
manure in 1974. The soil pH increased
from 5.7 to 7.2 and remained above 6.9
until 1983 as a result of this single
application (Table 1) . In addition, the
application of composted manure
increased the level of organic matter to
over 8% and the concentration of
exchangeable calcium was as high as 2500
ppm. In 1983 the organic matter
concentration had decreased to 4.5%,
whereas the concentration of
exchangeable calcium remained high (1900
ppm) . The cation exchange capacity was
10.2 meq per 100 g and the base
saturation was 114% in 1983.

A single application of granular
sulfur was applied at the rate of 0,
890, 1780, 2670 and 3560 Ibs/ac in
October 1984. During the same period,
concentrated sulfuric acid was applied
at the rate of 890 and 1780 Ibs/ac of

Table 1

Effects of applying six inches of composted lime-
treated horse manure on soil properties at the Saratoga
Tree Nursery, New York.

Year

- ppm

1974^

5.7

3.6

0.06

396

1975

7.3

9.1

0.21

297

462

1216

338

1976

7.0

8.4

0.21

250

210

1426

355

1977

6.9

9.1

0.22

278

178

2509

549

1983

7 . 1

4.5

0 . 15

230

1900

231

^ Horse

manure

was applied after

the 1974

samples

were

collected .

sulfur. In addition, two combination
treatments were established with gran-
ular sulfur and sulfuric acid each being
applied at the rates of 890 and 1780
Ibs/ac of sulfur. Each treatment was
replicated three times. Norway spruce
seeds were sown eight months after the
application of sulfur.

Soil samples of the surface six
inches were collected before treatments
were applied, at time of sowing Norway
spruce seeds, at the end of each growing
season, and during the spring of the
second growing season. Number of
seedlings per foot of seedbed was
determined in October, 1985 and October,
1986. Seedlings were lifted from the
seedbeds in October, 1986, and measured
for total height, root collar diameter
and root volume (Burdett 1979) .
Additional seedlings were lifted in
April, 1987, and measured for total
height and root collar diameter. Ten
seedlings from each nursery treatment
plot were used for root growth capacity
determination in April, 1987. Root
growth capacity was determined by
counting the number of white root tips
per seedling after growing in the
greenhouse for 28 days (Ritchie 1985) .

RESULTS

Soil pH in the study area was 6.5
before treatments were applied. This
soil pH was lower than the observed 6.8
to 7.0 found in other parts of the prob-
lem area because of the application of
840 Ibs/ac of sulfur in the spring
before the study was established. At
time of treatment, the organic matter
concentration was 3,0%; cation exchange
capacity was 7.2 meq per 100 g; and
concentrations of exchangeable calcium
and magnesium were 1097 and 138 ppm,
respectively. The base saturation was
92%.

A significant decrease in soil pH
was observed eight months after sulfur
application (Table 2) , The application
of 1780 Ibs/ac of granular sulfur plus
1780 Ibs/ac of sulfur as sulfuric acid
resulted in further lowering soil pH
compared to the other sulfur treatments
and was the only treatment to reduce the
soil pH to the desired range. After 23
months, the higher combination treatment
of sulfur plus sulfuric acid still had a
significantly lower soil pH as compared
to the control (Table 2) .

Table 2. Changes in soil pH of treatment plots as a result of

applying sulfur and sulfuric acid at the Saratoga Tree
Nursery, New York.

Treatment Months since treatment

Sulfur Acid^

(Ibs/ac) 0^ 8 12 20 23

6.9

6.8

890

6.7

6.6

890

6.4

abc

6.8

. 7

890

6.4

abc

6.7

. 7

1780

6.2

bed

6.6

2670

6.2

bed

6.5

3560

6.1

6.5

1780

6.2

bed

6.5

1780

5.6

6.1

The acid treatment is Ibs/ac of sulfur as sulfuric acid.
^ Month 0 is at time of treatment.

^ Values followed by the same letter within a column are not
significantly different at P = 0.05.

Seedbed density at the end of the
first growing season was influenced by
the application of sulfur and sulfuric
acid (Table 3) . The plots that received
sulfuric acid had significantly more
seedlings per foot of seedbed compared
to the control plots.

One beneficial aspect of many nurs-
ery soil amendments is the improvement
in seedling quality. After two growing
seasons seedlings growing in the plots
which had received sulfur or sulfuric
acid were significantly taller than the
seedlings grown in the control plots
(Table 4) . Seedlings from the plots
that received the heavier application of
sulfur plus sulfuric acid were almost
twice as tall as seedlings from the
control plots. This mean total height
represents all seedlings in the plot,
including the culls.

Seedling root collar diameter at
the end of the second growing season was
also related to the application of
sulfur (Table 4) . The seedlings in
plots receiving the higher rate of
granular sulfur plus sulfuric acid had
significantly larger root collar
diameters than those in plots which
received only sulfur or sulfuric acid.
Seedlings in the control plots had the
smallest root collar diameters.

Table 3. Seedlings per foot of seedbed
as influenced by the addition
of sulfur and sulfuric acid
at the Saratoga Tree Nursery,
New York.

Treatment Seedlings per foot

Sulfur Acid^ of seedbed

(Ibs/ac) 1-0 2-0

1780

120

111 a

2670

100

99 ab

1780

99 ab

890

95 abc

890

88 abc

890

8 6 abc

3560

80 be

1780

69 cd

53 d

^ The acid treatment is Ibs/ac of sulfur
as sulfuric acid.

^ Values followed by the same letter
within a column are not signifi-
cantly different at P = 0.05.

Root volume of the seedlings in
plots receiving the higher rate of
granular sulfur plus sulfuric acid was
significantly greater than the control
plots (Table 4) . The heavier applica-
tion rate of granular sulfur plus
sulfuric acid produced more new roots
tips than the control and, therefore,
had a higher root growth capacity (Table
4) .

Morphological measurements of
seedling quality were related to soil pH
at time of sowing Norway spruce seeds,
but not with soil pH at the end of the
first growing season or during the
second growing season. Variables
strongly correlated with soil pH at time
of sowing were seedling height, root
collar diameter and root growth
capacity. The only variable weakly
correlated with soil pH at the time of
sowing was root volume.

Seedlings lifted in the fall of
1986 and spring of 1987 were graded to a
minimum standard (root collar diameter
being 0.09 inches and height being 3.5
inches) (Reese and Sadreika 1979) . This
grading indicated that over 60% of the
seedlings grown in all sulfur plots were
plantable, whereas less than 40% of the
seedlings grown in the control plots
were acceptable (Table 5) . The heavier
application of granular sulfur plus
sulfuric acid resulted in the largest
percentage of large and medium size
seedlings and the smallest percentage of
cull seedlings. The control plots had
the largest percentage of culls. The
percentage of large, medium and cull
seedlings was strongly correlated to
soil pH at time of sowing.

Another beneficial aspect of
nursery soil treatment is the increase
in the number of plantable seedlings per
unit area. The largest number of
plantable seedlings was produced in the
plots that received the heavier
application of granular sulfur plus
sulfuric acid (Table 6) . The lowest
number of acceptable seedlings was
produced in the control plots. The
number of seedlings per foot of seedbed
and the cull percentage have been shown
to be related to sulfur treatment and
soil pH at time of sowing Norway spruce
seeds .

Table 4. Morphological characteristic of 2-0 Norway spruce

seedlings as influenced by the application of sulfur
and sulfuric acid treatments at the Saratoga Tree
Nursery, New York.

Treatment Height Diameter Root volume Number of

Sulfur Acid"^ (in) (in) (cm^) white root

tips

1780

. 14

0 .

100

1780

.41

.086

.48

3560

.29

.090

. 01

890

.22

.086

.88

abe

2670

. 01

.080

. 17

bed

890

.81

. 079

.48

abc

890

.73

.082

. 00

1780

.46

. 077

. 94

abc

. 15

.063

.45

Acid treatment is Ibs/ac of
^ Values followed by the same
significantly different.

sulfur as sulfuric acid,
letter within a column are not

Table 5. Percentage of seedlings by size class as influenced by
the application of sulfur and sulfuric acid treatments
at the Saratoga Tree Nursery, New York.^

Treatment

Sulfur Acid^ Large Medium Small Cull

(Ibs/ae) _______ Percent ---------

1780

26.

32 .

9d '

19.

3560

. 0 abed

. 4

1780

. 3 abed

. 1

890

.2 abed

2670

. 4 abc

. 8

890

.4 bed

. 1

890

bed

.4 a

. 6

1780

. 0 ab

. 9

. 6 cd

. 4

Large, .size .seedlings : >0 . 1 L'' diameter and >7,. 5" height ,^
Medium size seedlings: >T) . ID^' diameter and >6.3^' neight

Small size seedlings: >0.09" diameter and >3.5" height

Cull seedlings: <0.09" diameter or <3.5" height

^ Acid treatment is Ibs/ac of sulfur as sulfuric acid.

^ Values followed by the same letter within a column are not
significantly different.

DISCUSSION

Results observed from the
application of sulfur and sulfuric acid
at the Saratoga Tree Nursery revealed
that the soil pH at time of sowing and
germination of Norway spruce seeds was
imp'' ;tant in producing quality
seedlings. With the expection of root

volume, all variables of seedling
quality were affected by the soil pH at
the time of sowing. The higher
application rate of sulfur plus sulfuric
acid yielded the lowest soil pH and the
highest quality of seedlings.

These results differed from those
observed at the Orono Nursery, located
near Toronto, Ontario (Mullin 1964) . At

the Orono nursery sulfur was applied at
0, 750, 1500 and 2250 pounds per acre,
and at the end of three years, soil pH
was reduced from 7.4 to 6.5, 6.0, 5.3
and 5.0, respectively. The reduction in
soil pH of the control plots at the
Orono Nursery may have been the result
of the application of ammonium sulfate
fertilizer the first year and ammonium
nitrate the remaining two years of the
study. With the exception of the 2250
Ibs/ac treatment, seedlings produced in
sulfur treated plots were taller,
thicker (larger root collar diameter) ,
and heavier with a lower top-root ratio
than seedlings grown in the control
plots. The 2250 Ibs/ac treatment
resulted in increased mortality of
seedlings at the end of the first
growing season.

The different results obtained in
reducing soil pH with the high
application rates of sulfur in the
Ontario study and the Saratoga study may
be related to the differences in cation
exchange capacity and buffering capacity
of the soils. Another contributing
factor is that the organic matter
applied at the Saratoga Tree Nursery
contained large amounts of calcium and
magnesium and served as a buffering
agent. In fact, the application of six
inches of composted lime-treated horse

Table 6. Number of plantable seedlings
per foot of seedbed as
influenced by the application
sulfur and sulfuric acid at
the Saratoga Tree Nursery, New
York.

Treatment

Sulfur Acid^ Number of
(Ibs/ac) seedlings

1780

2670

abc

890

abc

3560

bed

890

bed

890

1780

Acid treatment is _lbs/ac of sulfur
as sulfuric acia.

^ Values followed by the same letter

within a column are not

significantly different.

manure was equivalent to applying 3.5
tons per acre of lime.

At the Saratoga Tree Nursery the
reduction of soil pH by most treatments,
however, was only for a short duration.
The effect of the addition of 3560
Ibs/ac of granular sulfur on soil pH is
undetectable 20 months after applica-
tion. In contrast, the application of
1780 Ibs/ac of granular sulfur plus 1780
Ibs/ac of sulfur as sulfuric acid showed
a reduction of soil pH for at least 23
months. Primarily analyses indicate a
treatment of 1780 Ibs/ac sulfur plus
1780 Ibs/ac sulfur as sulfuric acid is
an acceptable method of lowering soil pH
to obtain high quality seedlings.

Most of the study plots at the
Saratoga Nursery that received sulfur or
sulfuric acid had seedbed densities
above the recommended 60 .to 70 seedlings
per foot of seedbed (Richards et al.
1973) at the end of the second growing
season. The addition of sulfur plus
sulfuric acid combined with the opera-
tional sowing rate crated conditions for
high seedbed density. Consequently,
individual seedling weight may decrease
as seedbed density increases because of
decreased seedling branching (Richards
et al. 1973) . By using the higher
sulfur plus sulfuric acid treatment in
conjuction with a lower sowing rates,
desirable seedbed densities of high
quality seedlings may be produced at a
reasonable cost. A cost-benefit analysis
needs to be conducted to examine
economic benefits.

Results of the Saratoga study were
also similar to other studies where the
number and size of seedlings increased
as a result of applying sulfuric acid
(Hartley 1917) . In fact, the application
of sulfuric acid provided two
benefits: (1) increased the soil acidity
and (2) acted as a soil sterilizer.
Before organic fumigants were developed,
sulfuric acid was often used as a soil
sterilizer (Stoeckeler and Slabaugh
1965) . High populations of Fusarium
reported by Plumley (1986) at the
Saratoga Nursery may have been
controlled by the application of
sulfuric acid.

Although heavy applications of
sulfur and sulfuric acid improved
seedling quality at the Saratoga Tree
Nursery, I must stress that these heavy
application rates may not be acceptable
at all nurseries and all species.
Testing with small plots are needed to
determine beneficial rates and any
potential adverse effects.

CONCLUSIONS

1. The effect of applying six
inches of composted lime-treated horse
manure resulted in an increase in soil
pH; a condition that has persisted for
at least 12 years.

2. The heavy application of sulfur
resulted in a signicant decrease in
soil pH eight months after application.
The greatest decrease in soil pH was
achieved with the application of 1780
Ibs/ac of granular sulfur plus 1780
Ibs/ac of sulfur as sulfuric acid.

3. No significant differences were
detected in soil pH twenty months after
the application of sulfur or sulfuric
acid. The combination of sulfuric acid
plus sulfur decreased soil pH for at
least 23 months.

4. The application of sulfur
resulted in larger seedlings. The
largest seedlings were produced in plots
receiving the higher application rate

of granular sulfur plus sulfuric acid.

5. Measures of seedling quality
strongly correlated with soil pH at time of
sowing Norway spruce seeds were height,
root collar diameter and root growth
capacity .

6. The application of sulfur
reduced the percentage of cull seedlings
and increased the number of seedlings
per foot of seedbed.

LITERATURE CITED

Armson, K.A. and Sadreika, V. 1979.

Forest Tree Nursery Soil Management
and Related Practices. Ontario
Ministry of Natural Resources.
Toronto, Ont .

Benzian, B. 1965. Experiments on

nutrition in forest nurseries.
Forestry Comm. Bull. No. 37. Her
Majesty's Stationery Office.
London .

Burdett, A.N. 1979. A nondestructive

method for measuring the volume of
intact plant parts. Can. J. For.
Res. 9:120-122.

Hartley, C. 1917. The control of
damping-off of coniferous
seedlings. Bull. 453. US Dept. of
Agriculture. Washington, DC.

Manion, P.D. 1981. Tree Disease

Concepts. Prentice-Hall, Inc.,
Englewood Cliffs, NJ.

Mullin, R.E. 1964. Acidification of a

forest tree nursery soil. Soil Sci
Soc. Amer. Proc. 28:441-444.

Plumley, K.A. 1986. Fusarium as a cause
of seedling mortality at the
Saratoga Tree Nursery, Saratoga
Springs, New York. M. S. Thesis.
State Univ. New York, Coll.
Environ. Sci. and Forestry.
Syracuse, NY.

Reese, K.H. and Sadreika, V. 1979.

Description of bare root shipping
stock and cull stock. Ontario Min
of Nat. Res. Toronto, Ont.

Richards, N.A., Leaf, A.L., and

Bickelhaupt, D.H. 1973. Growth and
nutrient uptake of coniferous
seedlings: comparison among 10
species at various seedbed
densities. Plant and Soil 38:125-
143.

Ritchie, G.A. 1985. Root growth

potential: principles, procedures,
and predictive ability, p: 93-105 i
M.L. Duryea (ed.) Evaluating
Seedling Quality: Principles,
Procedures, and Predictive
Abilities of Major Tests. Forest
Research Lab. Oregon State Univ.
Corvallis, OR.

Scholtes, J.R. 1985. 1985 Northeastern
area state owned nursery
production. USDA Forest Service
Northeastern Area.

Stoeckeler, J.H. and Arneman, H.F. 1960
Fertilizers in forestry. Adv.
Agron. 12:127-195.

Stoeckeler, J.H. and Slabaugh, P.E.

1965. Conifer nursery practice in
the pariries-plains . Agri. Handb.
279. USDA Forest Service.
Washington DC.

Thompson, B.E. 1985. Seedling

morphological evaluation--what you
can tell by looking. p:59-71 in
M.L. Duryea (ed.) Evaluating
Seedling Quality: Principles,
Procedures, and Predictive
Abilities of Major Tests. Forest
Research Lab. Oregon State
Univ. Corvallis, OR.

Tinus, R.W. 1980. Nature and management
of soil pH and salinity, p 72-86 in
Proc. North American Forest Tree
Nursery Soils Workshop. State Univ.
New York, Coll. Environ. Sci. and
Forestry. Syracuse, NY.

van den Driessche, R. 1969. Forest

nursery handbook. Res. Notes No.
48. Brit. Columbia. For. Serv,
Victoria, B. C.

van den Driessche, R. 1979. Soil
management in Douglas-fir
nurseries, p 278-292 in P.E.
Heilman, H.W. Anderson, and
D.M. Baumgartner (ed) Forest soils

of the Douglas-fir region.
Washington State Univ. Pullman, WA

Western Fertilizer Handbook. 1980. The
Interstate Printers & Publishers,
Inc. Danville, IL.

White E.H., Comerford, N.B. and
Bickelhaupt, D.H. 1980.
Interpretation of nursery soil and
seedling analysis to benefit
nursery soil management, p 269-288
in Proc. North American Forest
Tree Nursery Workshop. State Univ.
New York, Coll. Environ. Sci. and
Forestry. Syracuse, NY.

Certified Vendor Program^

Thomas G. Boggus^

Abstract. --With demands for timber resources and the
cost of reforestation rising, inconsistency in planting
standards, and several important groups impacted by the
success or failure of each planting effort, the Texas
Forest Service, in 1982, initiated its Certified Vendor
Program. Now, through specific guidelines, inspection and
training, more energy can be spent reforesting new NIPF
lands, knowing current cases have been properly planted.

INTRODUCTION

The common goal of everyone involved in
reforestation is to successfully establish a
stand of healthy trees in the field. No matter
what facet of the process you may be involved
with, all efforts are concentrated at this one
goal. As the demand for the resource continues
to rise along with the costs of reforestation,
the ability to reach this goal is becoming more
and more challenging.

During the planting season of 1987, 1.12
million acres were artificially reforested in
the southeastern United States on nonindustrial
private forest lands. Using an estimated cost
per acre of $115.00 for site preparation,
seedlings and labor, that acreage figure
represents an annual investment of over 128
million dollars in reforestation. The East
Texas contribution amounts to 22,500 acres and
$1.57 million annually with almost equal amounts
being invested by the landowners and the three
cost-sharing programs available in the state.
These figures offer striking evidence that
mistakes resulting in increased seedling
mortality are extremely costly. In 1982, the
Texas Forest Service began implementing a
Certified Vendor Program in a effort to reduce
mistakes during the time the trees leave the
nursery and are planted in the field.

'Paper presented at the Intermountain Nursery
Association. Oklahoma City, Oklahoma, August 10-
14, 1987.

^Thomas G. Boggus is Staff Forester III,
Texas Forest Service, College Station, Texas.

REASONS FOR THE PROGRAM

Resource Demands

Results of the recently completed U.S.F.S.
Forest Survey of East Texas reveal that removals
of softv/ood have exceeded growth over the last
few years (Fig. 1). Much of this trend, along
with the potential for changing it, can be
explained by looking to the nonindustrial
private landowner (NIPF). This group owns
approximately 60% of the commercial Forest land
in Texas and yet has the poorest record
historically in reforesting following a harvest.

Currently, only one acre in nine is reforest
by NIPF landowners in Texas (Fig. 2). Given
that figure, it is imperative that this
important "acre" survive after being planted.
Thus, one reason for the Certified Vendor
Program is to improve the odds of survival
through proper handling and planting methods.
Of course, promotional and educational efforts
continue to work towards seeing more of the
other "eight acres" planted.

Program Consistency

A second reason for the vendor program was
the need to bring consistency to the NIPF
regeneration program. Prior to beginning the
program, there were years where we were losing
8,000-12,000 acres per year when it could not be
explained away by "dry weather." Seedling
counts across East Texas revealed 500-550
seedlings per acre were being planted versus the
726 per acre called for in the management
plans. Foresters had as many different ways of

550

MILLION CUBIC rEtrr

HARVEST ; GROWTH

500 -

450

400

350

300

1970 1980 1990 2000 2010 2020 2030

Figure 1. --Historic plus projected harvest
versus growth figures for East Texas
(USDA, 1987).

inspecting the jobs as the agency had
foresters! Not to mention there was no standard
means of comparing one vnedor or job to the next
and, therefore, good vendors were not being
rewarded for excellence and poor vendors were
taking advantage of the system, the agency and
the landowners.

Groups Impacted

Another imporant reason for the Certified
Vendor Program is the group of people impacted
by the success or failure of a tree planting
job. This group includes landowners, funding
institutions and planting vendors.

More than any other group, tree planting
will have the greatest impact on landowners.
Not only do they invest their hard earned
savings into the project, they also make the
decision to invest 20-30 years of their lives
into these 6 to 8 inch tall trees. Survival is
the first hurdle to pass but the next 19
risk-filled years are theirs to bear as well.
The vendor program is aimed at helping clear
that first hurdle with vigorous, healthy trees.

Since nearly all NIPF landowners in Texas
take advantage of one of the three programs
currently operating in the state that share the
financial burden of reforestation, these funding
institutions are also impacted by the success or
failure of a job. Limited funds and the
continued rise in reforestation costs mandate
that the tracts requiring re-planting be kept to
a minimum. The Certified Vendor Program helps
reduce the amount of re-planting caused by poor
planting methods.

Not Regenerated

Regenerated

Figure 2. --Comparison of NIPF acres regenerated
fol lowing harvests.

Tree planting vendors themselves are also
impacted by their own planting jobs. A vendor
has his/her livelihood and reputation riding on
each planting effort. Since its inception, many
vendors have commented on how this quality
control type program is like having a "silent
supervisor" on each NIPF tract their crews plant.

Cumulative Effect

Dr. S. J. Rowan (1987) recently released the
results of study on the effects of tender loving
care(TLC) from lifting to outplanting on
survival. Although TLC produced positive
results throughout the process, he concluded
that nothing had a greater impact on survival
than did proper handling and care during the
actual transplanting in the field. This
cumulative effect on survival is further
magnified when consideration is given to the
rather unique geographic location of Texas'
commercial forestland. Planting pines in the
western fringe area of the Great Southern Yellow
Pine Forest demands extra care and, thus, the
Certified Vendor Program.

KEYS TO SUCCESS

Having established the obvious need for the
vendor program, the next step is to develop a
clear set of objectives. The three main
objectives of the Texas Certified Vendor's
Program are:

1. Insure quality reforestation

2. Develop a qualified vendor community

3. Allocate work fairly

The keys to the success or failure in
reaching these objectives lie in the methods
chosen to implement the program.

Insure Quality Reforestation

Quite obviously, the primary objective of
the Certified Vendor Program from its inception
was to deliver a quality reforestation effort to
NIPF landowners. Moving to meet this goal,
however, required more care and planning than
would the other two. The keys here are to
develop a good set of technical guidelines,
implement a uniform method of inspecting the
work and train the personnel responsible for
carrying out the program on the ground.

Technical Guidelines

The beginning point to insuring a quality
reforestation effort is for all parties involved
to be working within the same framework. In
Texas, we developed a set of technical
guidelines covering the three main topics of
site preparation, planting and timber stand
improvement. Each topic is further broken down
into smaller sections which spell out in detail
what practices are permitted, how to carry them
out and what the minimum limits of acceptability
are for each practice. Every forester,
technician and vendor is supplied with, or has
access to, a copy of these guidelines so
everyone knows, in advance, what is expected of
them.

For example, here is how "reforestation" is
further broken down into sections. There are
seven sections which include planting rates,
planting methods, seedling care, protection of
seedlings, environmental considerations, vendor
certification and vendor completion
requirements. Everyone involved with
reforestation on any given NIPF tract is working
under the same rules and knows the consequences
for breaking them. Of course, these guidelines
are only good as long as there is some way to
verify they are being complied with, which means
on site inspections.

Inspection

The strength and credibility of the vendor
program center around the inspection process.
Almost every NIPF tract planted in East Texas is
inspected by a trained tree planting inspection
crew. These two-man crews systematically check
1 /100th acre plots over an entire area, with the
number of plots per tract dependent upon actual
tract size (table 1 ) .

Upon arrival at each plot site, the plot is
numbered and marked with a wire flag in case it
is necessary to return to that particular plot.
Next, the total number of trees per plot are
counted by using a 1/lOOth acre tape or rope and
that number is recorded on a data sheet. Then
the trees within the plot are checked for "above
ground problems" (table 2) such as debris in the
hole or planted too shallow. Finally, before

Table 1. --Number of plots taken based on the size
of the tract and approximate distance
between plots in Gunters chains.

Tract I
Size of Dist.

(acres) Plots (chains)

0-60 1 per ac 3.25

61-90 1 per 2 ac 4.50
91+ 1 per 3 ac 5.50

leaving a plot, two trees are carefully

excavated outside of the plot itself to inspect

for any below ground problems like severe root

pruning or "J" rooting (table 2).

Table 2.--A list of specific above and below
ground problems inspection crews look for
at each plot.

Above Ground Problems

Debris in hole Cull seedlings

Too shal low Too deep

Not packed Unidentified

Below Ground Problems

Excessive angle "J" rooting

"L" rooting Twisted roots

Pruned improperly Cull seedlings

Before leaving the planting site, the
inspection is completed by checking seedling
bundles and counting and culling two bundles of
seedlings, if possible. The bags are checked
for species type to insure the right species is
planted on each tract and the bag dates for when
the bundles left the cold storage. Vendors have
14 days to either plant the trees or heel them
in after the seedlings leave cold storage.
Failure to do so results in bag confiscation and
replacement seedlings must be furnished by that
vendor. The seedling bundle count provides
important information to the nursery as to how
many plantable trees per bag are leaving the
nursery. This is especially important since the
data is received during lifting and grading so
adjustments can be made as needed.

Since the inspection process is so important
to the success or failure of the program, some
means of "inspecting the inspectors" or quality
control is vital. In Texas, we have quality
control people in each management area whose job
it is to spot check every inspection crew

working in their area. The crews never know
where or when the quality check will be
performed and poor job performance could mean a
severe reprimand or their jobs.

Training

From the previous section it becomes
apparent that a virtual army of inspectors is
needed. That entails training this army
initially and then continuing to update them on
any changes from year-to-year plus refresher
courses. The source of manpower for these
inspectors came from our forest technician ranks
who were, up to this point, primarily considered
fire fighters. Their number one priority is
still to suppress wildfires, however wildfire
suppression does not require the bulk of their
time except for generally short periods of time
during the year.

Tree inspection training requires about
three days to complete. The first day is spent
in a classroom session reviewing the technical
guides, plot procedure, mathematics involved in
working up the data, and other matters
concerning the inspection of a tree planting
job. The next two days are spent in the field
in "hands-on" type exercises with individual
instruction at each station. Both the classroom
and field exercises have exams the trainees must
pass prior to becoming a certified inspector.

Develop a Qualified Vendor Community

Approximately 22,500 acres of NIPF lands
are reforested annually in East Texas. Even
though this level of planting pails in
comparison with some other southeastern
states, it is impossible for the Texas Forest
Service personnel to plant this acreage and
undesired, even if it were possible.
Therefore, it is imperative that a qualified
community of vendors be developed to handle
the work. To begin to accomplish this, we
must once again turn to training.

As stated, each vendor interested in
planting trees in NIPF lands in East Texas is
supplied with a copy of our technical
guidelines. Additionally, we require a vendor
to attend one of the day-long meetings held at
different locations and dates during the
fall. During these meetings, the vendors have

explained in detail the requirements of the
program, technical guides, inspection process
and other matters concerning planting season
through a multimedia presentation and
question-answer session. At the conclusion of
every meeting, the vendors wishing to
participate in the Certified Vendor Program
sign an agreement stating they will plant
according to the guidelines. The requirements
are tough but fair and our list of vendors
grows each year.

Al locate Work Fairly

The final objective to meet after
everything else has been implemented is to
find a means of allocating the work to the
vendor community. The best method we have
found is through the use of the sealed
competitive bid system. Not only does this
remove the agency from any bias in vendor
selection, it also keeps reforestation costs
down for the landowner due to vigorous
competition. Landowners, not the Texas Forest
Service, have the option to accept or reject
the bids received on each tract. Since the
vendors must meet minimum requirements under
the program and vendors are not paid until
these requirements are met, the landowner is
assured of a quality planting job.

CONCLUSION

With the increasing demands for forest
resources and planting mistakes resulting in
reforestation failure becoming more costly,
the Texas Forest Service has begun to take
steps to meet both problems. In essence, we
take this saying to heart, "you can achieve
results two ways: expect it or inspect for
it"l We expect a great deal from our own
people and the vendors, but then we make
inspections to insure we get it.

LITERATURE CITED

Lang, Linda L. and Daniel F. Bertelson. Forest
Statistics for East Texas Counties 1986.
USDA Southern Forest Experiment Station, New
Orleans, Louisiana.

Rowan, S. J. 1987. Nursery seedling quality
affects growth and survival in outplantings,
Georgia Forest Research Paper 70. 13 p.
Georgia Forestry Commission, Athens, Georgia.

Alternative Methods to Evaluate Root Growth Potential
and Measure Root Growth^

W. J. Rietveld and Richard W. Tinus^

Abstract. — This paper reports experiments that compared
root growth potential (RGP) testing methods, methods of quan-
tifying root growth, and diagnostic ability of test methods.
Factors that affect root growth in RGP tests are discussed.
New root growth and plant water potential patterns of jack
pine seedlings in pot, hydroponic, and aeroponic culture were
similar, but new roots appeared first in hydroponic and aero-
ponic culture. The simplest method of quantifying root growth
is to measure the number of roots longer than a minimum
length. Electronic measurement of root area index is fast
and well correlated with root number and length, but the
equipment cost makes it most suitable for large operations.
Test method and test length may affect results. Fourteen-
day pot and aeroponic culture tests of jack pine seedlings
subjected to root exposure treatments accurately diagnosed
the weakened seedlings, but the seedlings recovered in 28-day
tests, especially in aeroponic culture. For new applica-
tions, it is recommended that preliminary screening tests
be run to determine the most suitable testing conditions.

INTRODUCTION

Root growth potential (RGP) is the most
important measurable attribute of physiological
quality because it quantifies the ability of
seedlings to initiate and elongate new roots
promptly and abundantly after transplanting.
RGP is unique because it integrates an array of
physiological factors into a single biologically
meaningful estimate of performance potential —
the ability to grow new roots. Much information
has been published on RGP in the past few years.
Available evidence to date indicates a strong
relation between RGP and field survival and
growth (Ritchie 1985). Factors that affect the
development and expression of RGP were extensive-
ly reviewed by Ritchie and Dunlap (1980), the
relation of new root growth to several seedling
and environmental factors was discussed by Carlson

^Paper presented at the Intermountain Forest
Nursery Association Meeting, Oklahoma City,
Oklahoma, August 10-14, 1987.

2W.J. Rietveld is Research Plant Physiolo-
gist, North Central Forest Experiment Station,
Rhinelander, Wisconsin; Richard W. Tinus is
Research Plant Physiologist, Rocky Mountain
Forest and Range Experiment Station, Flagstaff,
Arizona.

(1986), and the role of new root growth in the
mechanism of transplanting stress was discussed
by Sands (1984).

In contrast to most morphological quality
measurements, which can be measured almost instan-
taneously, physiological quality attributes take
time to measure (except for plant moisture stress).
Consequently, it is not yet feasible to test stock
and grade it physiologically before shipping.
Until a faster method is available to estimate
RGP, e.g. via a connection with cold hardiness
(Ritchie 1985; Tinus, et al. 1986), we must be
content to rely on present root growth tests to
document RGP, and obtain the results in 2-4 weeks,
usually after the seedlings have left the nursery.

Many people have hesitated to become involved
in RGP testing because of: (1) equipment costs,
(2) long test length, and (3) labor requirements
and tedium of taking data. For the most part,
these drawbacks are more imagined than real. The
many variations on the original 28-day RGP test
are summarized by Ritchie (1985). RGP tests may
be shortened to as little as 7 days for certain
species (Burdett 1979) , and root growth may be
quantified by new root number, length, volume,
area index, or dry weight. In this paper we will
focus on: (1) selection of methods to test the
seedlings; (2) alternative methods to measure
new root growth; and (3) the effects of testing

method, test conditions, and test length on
results .

COMPARISON OF TESTING METHODS

Although many different growing systems and
media have been tried, the three main methods
currently used to test seedlings are pot culture,
hydroponic culture using an aquarium, and aero-
ponic culture using a root misting chamber. Pot
culture is the traditional method (Stone 1955) .
It appears to be straight forward and inexpen-
sive, but two important test conditions must be
satisfied: (1) root temperature must be kept
uniform, and (2) the growing medium must be well
aerated. To provide a uniform root temperature,
a growth room or water bath system is usually
required, which raises the cost to a level com-
parable with other methods. Well-designed and
relatively inexpensive hydroponic methods have
recently been reported (DeWald et al. 1985, Palmer
and Holen 1986) . Hydroponic culture keeps the
seedlings clean of growing medium, allows peri-
odic observation of the progress of root growth,
minimizes damage to new roots, and allows the
test seedlings to be grown in fewer containers,
while maintaining uniform root temperature and
aeration within containers. It is important that
aeration be gentle and uniform among containers,
otherwise the agitation may inhibit root growth
and increase variation. Aeroponic culture in a
root misting chamber is another new technique.
It was originally reported by Lee and Hackett
(1976), refined by Harvey and Day (1983), and
more recently refined by Rietveld and Tinus
(1987). The root misting chamber has the same
advantages as hydroponic culture, plus it is
portable and provides a uniform temperature,
humidity, and aeration environment for the roots
in one container.

at the same time root growth was measured. Data
were subjected to analysis of variance and
Bartlett's test of homogeneity of variances.

New root growth was observed first in the
root misting chamber and in hydroponic culture on
day 9, then in pot culture on day 11 (fig. 1).
Although seedlings grown in the root misting
chamber had consistently higher levels of new
root growth, the data were statistically indis-
tinguishable from the hydroponic and pot methods
on all measurement days, due to high among-seedling
variation. The variances of the three methods,
compared for the overall test and for days 14, 21,
and 28, were likewise indistinguishable.

Root size distributions on day 28 for seed-
lings tested by the three methods are shown in
figure 2. Although the patterns are similar for
roots less than 15 cm long, seedlings grown in the
root misting chamber and hydroponic culture had
more long roots, reflecting the earlier and faster
rooting apparent in figure 1. The response may
also reflect the lack of soil resistance to root
elongation.

The pattern of plant water potential in test
seedlings is shown in figure 3. Average potential
of seedlings taken from the cooler on day zero was
-0.5 bar. Within 1 day in the growth room, poten-
tial dropped (became more negative) to approxi-
mately -6 bars, bottomed at approximately -6.5
bars on day two, then gradually increased during
the course of the test to the range of -3 to -4
bars. The increase in plant water potential was
weakly correlated with the initiation of new roots
(r= -0.34), and may be better explained by osmotic
adjustment. There were no significant differences
in plant water potential among the cultural methods
on any of the measurement days.

While developing the new root misting
chamber, we needed documentation to show how the
new device compares with existing methods for
growing the test seedlings. To provide that
documentation, we grew overwinter-stored 2+0 jack
pine (Pinus banksiana Lamb) seedlings in pot
culture, hydroponic culture, and aeroponic culture
in the new root misting chamber, and compared new
root production, among-seedling variation , and
root size distribution. Potted seedlings were
grown in a mixture of 1:1:1 sand/perlite/vermicu-
lite with no fertilizer added. The hydroponic
system consisted of tree holders laid across a
large 20-cm-deep galvanized tank of water gently
aerated through aquarium stones. The three grow-
ing systems were located in a growth room set at
a constant 27° C temperature, 18 hour photoperiod,
and light intensity of 165 uE/m^/sec. The root
misting chamber was also set at 27° C. Seedling
root growth of 10 seedling samples was measured
after 9, 11, 14, 16, 18, 21, 23, 25, and 28 days
using a new root area index method (Rietveld and
Tinus 1987) . Number and length of new roots
longer than 0.5 cm were also measured on day 28.
Additionally, plant water potential of each test
seedling was measured, using a pressure chamber.

Q I , , I I , , I I I

9 12 15 IB 21 24 27
DAY OF TEST

Figure 1. Root growth potential of 2+0 jack pine
seedlings grown in aeroponic, hydroponic,
and pot culture, quantified as change in
root area index for nine test periods.

I—
o
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Li_
O

AEROPONIC CULTURE

llilliM--iJ,-,ih 1,-L,--.

HYDROPONIC CULTURE

HidiiiLLJL

POT CULTURE

ROOT LENGTH (cm)

Figure 2. Size distribution of new roots of jack
pine seedlings, on a per seedling basis,
after 28 days of growth in aeroponic,
hydroponic , and pot culture.

O
Q.

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<:
□_

8 12 16 20 24 28
DAY OF TEST

These data show that the three growing
methods produce similar growth patterns for
normal planting stock. Root growth was somewhat
faster in the root misting chamber than in hydro-
ponic or pot culture. For jack pine, 14 days
appears to be the minimum test length to obtain
an acceptable root growth response for evaluation.

COMPARISON OF METHODS TO MEASURE ROOT GROWTH

The task of quantifying new root growth may
seem initially formidable when you look at a
seedling that has up to 400 new roots on it, but
the job is not as big as it looks. Researchers
have devised many methods to lessen the task while
still obtaining meaningful data. Originally both
number of new roots and total length of new roots
were measured. Eventually it was found that root
number and root length are strongly correlated
(Stone and Schubert 1959), so only number of roots
longer than a minimum length was measured. Note,
however that the correlation would be expected to
decrease as test length increases because some of
the new roots grow quite long (see fig. 2).
Harvey and Day (1983) were the first to quantify
new root growth in RGP tests by change in root
area index using a Rhizometer (Morrison and
Armson 1968) , a photoelectric device developed
for seedling morphology measurements in Ontario.
Racey (1985) compared root measurement by root
area index (using the Rhizometer), volume, and
dry weight. He found strong correlations between
the three quantification methods and the calcula-
ted area of new root tips, and recommended root
volume because it was the easiest to measure.
However, the Rhizometer has problems detecting
new white roots at high light intensities (Racey
1985) , and root volume determined by the Archi-
medes principle (measuring weight increase when
the roots are dipped into a large beaker of water
on a balance) has problems due to lack of repeat-
ability of individual measurements (Ritchie 1985) .
A new root area index method for quantifying root
growth in RGP tests was developed by the authors
(Rietveld and Tinus 1987). The method is based
on a microprocessor area meter (Delta-T Devices,
Cambridge, England^) , and involves placing an
intact root system on a light box in view of a
black and white TV camera. The image is scanned
by the area meter, and a microprocessor totals
all the line segments in the viewing area that
are covered by roots. The method is very fast
(up to 500 seedlings/day), but the equipment costs
much more ($3670) than that needed to count the
new roots manually.

To provide documentation for the micropro-
cessor root area index method, we conducted a
test to determine the relation among new root
growth measured by change in root area index.

Figure 3. Plant moisture stress of 2+0 jack pine
seedlings grown in aeroponic, hydroponic,
and pot culture. Each point is the mean of
10 seedlings.

-^The use of trade or firm names in this
publication is for reader information and does
not imply endorsement by the U.S. Department of
Agriculture of any product or service.

counted number of new roots, and measured length
of new roots. To compare the methods over a
range of RGP, we gave 50 jack pine seedlings root
exposures of 0, 10, 20, 30, and 40 min by placing
them in a large forced-air oven at 40° C. The
seedlings were grown in a root misting chamber
located in a greenhouse with maximum air temper-
atures ranging between 18 and 28° C, minimum air
temperature of 15.5° C, photoperiod extended to
18 hours with high pressure sodium lamps, and
light intensity ranging from 300 to 800 pE/m^/
sec. The root misting chamber temperature was
set at 27° C, which is favorable for jack pine.
After 17 days, new roots >0.5 cm on each seedling
were measured manually, and all new roots were
measured by the root area index method. Root
growth measurements were compared by linear
regressions using individual seedlings as obser-
vations (n=50) . The coefficients of determina-
tion (r^) for change in root area index on total
number of new roots and total length of new roots
were 0.88 and 0.90, respectively (fig. 4). Total
number of new roots was closely related to total

length of new roots (r'^=0.93). These strong
relations indicate that measuring new root growth
as change in root area index is a valid quantifi-
cation method that provides a close estimate of
actual root number and length.

Change in root area index may be a better
estimate of rooting response than either root
number or root length because (1) it measures all
new roots, (2) it takes both root diameter and
length into account, and (3) it detects root
decrement as well as increment. However, the
root area index method does not distinguish the
origin of new roots and does not give any infor-
mation on individual root size classes, i.e. the
relative abundance of coarse and fine roots.

RGP TEST ENVIRONMENT AND SAMPLING

Although it is widely accepted that a uniform
and favorable root environment is most important
for conducting RGP tests, the shoot environment

CHANGE IN ROOT AREA INDEX (cm')

_ 400-1
E

CHANGE IN ROOT AREA INDEX (cm')

Figure 4. Regressions of root growth quantified by number of
new roots (NNR) and length of new roots (LNR) on change
in root area index (oRAI) , measured on the same seed-
lings. n=50. Several points represent multiple seed-
lings, especially those with zero NNR or LNR.

should also be favorable and repeatable when a
series of RGP tests are run and the results
compared. Abod et al. (1979) found that RGP of
Pinus caribaea Mov. and P. kesiya Royle ex
Gordon seedlings was optimized at air and soil
temperatures between 24 and 30° C, and light
intensity of approximately 50% of full sunlight
(500-750 /lE/m^/sec). The optimum temperature
for seedling root growth of many North American
species is near 20° C (Ritchie 1985). Root
growth potential tests are commonly run at ele-
vated root and shoot temperatures and extended
photoperiods . These conditions are well beyond
the normal environment when seedlings are trans-
planted, but test results are obtained in a
shorter time. Significant seed source and family
differences in optimum temperature for root re-
generation have been documented within a species
(Carlson 1986, DeWald and Feret 1985, Jenkinson
1980, Nambiar et al. 1982). Therefore, it is
advisable to experiment with root and shoot
temperatures, and test length to determine the
most suitable conditions for the species being
evaluated, as well as seedlot or family varia-
tion in response to temperature. If seedlot or
family variation is significant, it may be useful
to adjust RGP to a base temperature (e.g. 20° C)
for comparison.

chamber and pot culture. The experiment was
conducted in a large root misting chamber (0.9 m
wide x 3.7 m long) located in a greenhouse under
the same environment as the previous experiment.
Potted seedlings were suspended in the root mist-
ing chamber so that the root temperature in the
pots was maintained at the same temperature as
the misting chamber. New root growth was quanti-
fied by the root area index method described
above .

The results were quite surprising. At 14
days the root misting chamber and pot culture
methods gave the same diagnosis (fig. 5): i.e.
RGP of all root exposure treatments was signifi-
cantly lower than the control (0 min root exposure),
The root growth difference between control and
root exposed seedlings was substantially higher
when seedlings were tested in the root misting
chamber (fig. 5). In the 28-day test, however,
seedlings from many of the root exposure treat-
ments recovered, especially in the root misting
chamber. The testing methods did not give the
same diagnosis in the 28-day test: in pot culture,
only seedlings root exposed for 10 min recovered
(n.s. from control), while in the root misting
chamber seedlings in all root exposure treatments
recovered (all n.s. from control).

Another factor to consider is seedling size.
Seedlings with higher root volume have higher
RGP (Carlson 1986), so it is important that the
sample tested represents the range of seedling
sizes in the stock lot. Note that selecting
seedlings of uniform size for testing RGP would
give a biased estimate of RGP if the average
size of the sampled seedlings was not the same
as the mean size for the stock lot. To obtain
a true random sample that represents the range
of seedling size and condition in the seedlot,
the seedlings to be tested must be sampled from
many locations in the population.

For normal bed-run stock, we consider a
sample size of 25 seedlings to be minimum
because variation is often high in RGP tests
(Ritchie 1985, Sutton 1983). Depending on the
uniformity of the test plants and the precision
desired, 50 seedlings or more may be necessary.
Very uniform plant material, such as stock grown
by family (e.g. from seed collected from a clone
in a seed orchard) , may require fewer test seed-
lings .

It appears that under some conditions the
root misting chamber environment may be too favor-
able for root growth, so that weakened seedlings
may recover in longer tests (28 days) and show
acceptable RGP. This was true to some extent for
the potting method as well. In a 14-day test,
however, the two methods were equally capable of
diagnosing the weakened seedlings. These results
suggest that tests should be no longer than
necessary to detect differences in quality; longer
tests may result in greater variation among seed-
lings, recovery of weakened seedlings, and more
roots to measure. Additional research is needed
to determine all the implications of test method
and test length.

This experiment also demonstrated clearly
the difference in root growth rates between the
root misting chamber and pot culture. For the 0
min root exposure treatment, root area index
increment at 14 days was 16.2 for the root misting
chamber and 12. 1 in pot culture (significant at
0( = 0.05); at 28 days it was 60.6 for the root
misting chamber and 26.8 in pot culture (signi-
ficant at 0( = 0.005) .

DIAGNOSTIC ABILITY OF THE TEST METHODS

An additional question that needs to be
addressed is how do the methods compare in
diagnosing stock that differs in vigor — will
the same conclusions be reached using different
testing methods? To answer this question, we
generated several levels of seedling vigor by
subjecting jack pine seedlings from a common
seedlot to root exposures of 0, 10, 20, 30, 40,
and 50 min at 40° C in a large forced-air oven.
We then assigned 15-seedling random samples to
14-day and 28-day RGP tests in the root misting

SUMMARY AND CONCLUSIONS

1. RGP is the most important measure of seedling
physiological quality because it integrates
an array of attributes into a single biolo-
gically meaningful measure - the ability to
grow new roots. However, physiological grad-
ing is still not practical because RGP testing
is not immediate like morphological measurements

2. RGP testing in pot culture, hydroponic culture,
and aeroponic culture (root misting chamber)

X
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O

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cc

(J3

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<

X
CJ

Q_
CD

50-

RMC 28D

RMC 14D
y POT 14D

10 20 30

ROOT EXPOSURE (min)

Figure 5. Root growth potential, measured as change in

root area index, of 2+0 jack pine seedlings grown in
aeroponic and pot culture for 14 and 28 days.

gives similar root growth patterns. New root
growth was observed first in hydroponic and
aeroponic culture. The three methods require
approximately the same investment in equip-
ment when maintenance of uniform root temper-
ature is taken into account.

For smaller numbers of seedlings, it appears
that the simplest and least expensive method
of quantifying root growth is to count the
number of new roots longer than a minimum
length. This approach is based on a strong
relation between root number and root length.
The relation would be expected to weaken with
longer test periods (some roots grow very
long), but should still be satisfactory.
Measurement of root area index increment is
the easiest and fastest method of quantifying
new root growth, and is well correlated with
root number and length, but the equipment
cost makes it more suitable for large opera-
tions .

Test method and test length may affect test
results. Seedlings weakened from root

exposure treatments were found to recover in
28-day aeroponic tests, and to some extent in
pot culture. However, both methods accurately
diagnosed differences in seedling vigor in
14-day tests.

5. Root temperature, light intensity, seedling
size, test method, test length, species, and
seed source/family within species have all
been reported to affect RGP. If a series of
RGP tests will be run and the results compared,
it is advisable to run preliminary screening
tests before a set of testing conditions is
established. The "best" testing method and
conditions are those that meet specific needs
and objectives, and can distinguish differences
in physiological quality in the least amount of
time .

LITERATURE CITED

Abod, S.A. , K.R. Shepherd, and E.B. Bachelard.
1979. Effects of light intensity, air and
soil temperatures on root regenerating

potential of Pinus caribaea var Hondurensis
and P. kesiya seedlings. Aust. J. For.
Res. ~9: 173-184.

Burdett, A.N. 1979. New methods for measuring
root growth capacity: - their value in
assessing lodgepole pine stock quality.
Can. J. For. Res. 9:63-67.

Carlson, W.C. 1986. Root system considerations
in the quality of loblolly pine seedlings.
Southern Journal of Applied Forestry
10:87-92.

DeWald, L.E. and P.P. Feret. 1985. Genetic
variation in loblolly pine root growth
potential, p. 155-162 In Proceedings
18th Southern Forest Tree Imp. Conf. [Long
Beach, MS, May 1985] Pub. No. 40, Southern
Forest Tree Improvement Committee.

DeWald, L.E., P.P. Feret, and R.E. Kreh. 1985.
A 15-day hydroponic system for measuring
root growth potential, p. 4-10 Eugene
Shoulders (ed.), Proceedings 3rd Biennial
Southern Silvicultural Research Conference
[Atlanta, GA, November 7-8, 1984] USDA
Forest Service General Technical Report
SO-54, 589 p. Southern Forest Experiment
Station, New Orleans, LA.

Harvey, E.M. and R.J. Day. 1983. Evaluating

the root regeneration potential of conifer-
ous nursery stock by the potting and root
mist chamber methods. School of Forestry,
Lakehead Univ., Thunder Bay, Ontario. 103 p.

Jenkinson, J.L. 1980. Improving plantation

establishment by optimizing growth capacity
and planting time of western yellow pines.
USDA Forest Service Res. Pap. PSW-154, 22 p.
Pacific Southwest Forest and Range Experi-
ment Station, Berkeley, CA.

Lee, C.I. and W.P. Hackett. 1976. Root regen-
eration of Pistacia chinensis Bunge seed-
lings at different growth stages. J. Am.
Soc. Hort. Sci. 101:236-240.

Morrison, I.K. and K.A. Armson. 1968. The
Rhizometer - a new device for measuring
roots of tree seedlings. For Chron.
44:21-23.

Nambiar, E.K.S., P.P. Cotterill and G.D. Bowen.
1982. Genetic differences in the root re-
generation of radiata pine. J. Expl. Bot.
33: 170-177.

Palmer, Larry and Ivend Holen. 1986. The

aquarium tester - a fast, inexpensive device
for evaluating seedling quality. Tree Plant-
er's Notes 37(3):13-16.

Racey, G.D. 1985. A comparison of planting stock
characterization with root area index, volume
and dry weight. For Chron. 61:64-70.

Rietveld, W.J. and Richard W. Tinus. 1987. Eval-
uating root growth potential of tree seed-
lings with a root misting chamber and elec-
tronic measurement of root area index. New
Forests (in press) .

Ritchie, G.A. and J.R. Dunlap. 1980. Root growth
potential: its development and expression in
forest tree seedlings. N.Z. J. For. Sci.
10:218-248.

Ritchie, G.A. 1985. Root growth potential:

principles, procedures and predictive abil-
ity, p. 93-104 In M.L. Duryea (ed.). Evalu-
ating Seedling Quality: Principles, Proced-
ures, and Predictive Abilities of Major
Tests [Corvallis, OR, October 16-18, 1984]
College of Forestry, Oregon State University,
Corvallis.

Sands, R. 1984. Transplanting stress in radiata
pine. Aust For. Res. 14:67-72.

Stone, E.G. 1955. Poor survival and the physio-
logical condition of planting stock. For.
Sci. 1:90-94.

Stone, E.G. and G.H. Schubert. 1959. The physi-
ological condition of ponderosa pine (Pinus
ponderosa Laws.) planting stock as it affects
survival after cold storage. J. For.
57:837-841.

Sutton, R.F. 1983. Root growth capacity:

relationship with field root growth and per-
formance in outplanted jack pine and black
spruce. Plant and Soil 71:111-122.

Tinus, Richard W. , Karen E. Burr, Stephen J.

Wallner, and Rudy M. King. 1986. Relation
between cold hardiness, root growth capacity,
and bud dormancy in three western conifers,
p. 80-86 In Thomas D. Landis (ed.). Proceed-
ings: Combined Western Forest Nursery Council
and Intermountain Nursery Association Meeting
[Tumwater, WA, August 12-15, 1986] USDA
Forest Service General Technical Report
RM-137, 164 p. Rocky Mountain Forest and
Range Experiment Station, Fort Collins, CO.

Comparison of Time and Method of Mist Chamber
Measurement of Root Growth Potential^

Karen E. Burr, Richard W. Tinus, Stephen J. Wallner, and Rudy M. Klng^

Abstract. — Container-grown ponderosa pine, Douglas-fir,
and Engelmann spruce seedlings were cold acclimated and
deacclimated in growth chambers over 19 weeks. Weekly
whole-plant freeze tests and 7- and 14-day root growth
potential (RGP) tests indicated 7-day RGP results were
misleading during cold acclimation and that the 14-day test
period was preferable. During cold deacclimation , both RGP
test periods were suitable. Quantification of RGP as total
length and total number of new roots per seedling were
nearly equally informative from budset to bud break,
independent of the length of the RGP test.

INTRODUCTION

Root growth potential (RGP) is the ability of
a tree seedling to initiate and elongate new roots
when placed into an environment favorable for root
growth (Ritchie 1985) . It is a measure of seed-
ling physiological quality and vigor. To become
established in the field after outplanting,
seedlings must be able to utilize new soil
reserves of water and nutrients as those reserves
in immediate contact with existing roots are
depleted. New roots must be produced to accom-
plish this. Seedlings with a high capacity to
produce new roots are likely to become established
more rapidly and with less stress than comparable
seedlings with a low RGP. For this reason, RGP
measurements made prior to outplanting have been
found to be positively correlated with the field
survival and growth of many species of forest tree
seedlings (Burdett 1979, Burdett et al. 1983,
Jenkinson 1980, Ritchie and Dunlap 1980, Stone et
al. 1961). Measurement of the RGP attribute is
currently thought to be the most reliable
predictor of field performance of the various
seedling quality tests available (Ritchie 1985) .

RGP is commonly measured using one of three
approaches: the pot test, a hydroponic system, or
an aeroponic system. In the pot test, originally

^Paper presented at the Intermountain Forest
Nursery Association Meeting. [Oklahoma City,
Okla., August 10-14, 1987.]

^The authors are, respectively. Plant
Physiologist and Principal Plant Physiologist,
Rocky Mountain Forest and Range Experiment
Station, Flagstaff, Ariz.; Professor of
Horticulture, Colorado State University, Fort
Collins, Colo.; and Station Biometrician, Rocky
Mountain Forest and Range Experiment Station, Fort
Collins, Colo.

developed by Stone (Stone 1955, Stone and
Jenkinson 1970, Stone and Schubert 1959),
seedlings are potted, several per container, and
maintained for 28 days at 20 C under a 16-hour
photoperiod and as near field capacity as
possible. Seedlings are washed from the medium to
assess root growth. While this technique is
successful, it has disadvantages (Ritchie 1985).
Considerable time is required before results are
available, and plant maintenance during that time
is expensive. Potting and unpotting of seedlings
is not only labor intensive, but requires large
quantities of media, can result in root system
damage, and does not permit examination of the
root system prior to the end of the test period.
Burdett (1979) addressed the problem of the
lengthy test period by developing a 7-day test in
which root growth was accelerated by increasing
the day/night temperatures to 30 /25 C. The 7-day
and 28-day test results are well correlated in a
number of conifers (Ritchie 1985) , though not in
all species (Ritchie 1984).

The hydroponic system uses temperature-
controlled aerated water baths made from aquariums-
painted black and covered with lids which support
the seedlings with the roots submerged. Winjum
(1963) used a 28-day test period, while others
have successfully shortened the test to between 15
and 21 days (DeWald et al. 1985, Rose and Whiles
1985, Sutton 1980). Hydroponic systems eliminate
the disadvantages associated with potting and
unpotting of seedlings. Additionally, this
technique requires 50% less bench space than the
pot test, and the roots are easily measured
because they remain clean and unbroken. Ritchie
(1984, 1985) found that seedlings tested
hydroponically produced about the same length and
number of new roots as similar in concurrent pot
tests. However, hydroponic culture of tree
seedlings can result in steadily decreasing xylem
water potential and minimal new root production

(Rietveld 1986) . An additional problem suspected
with the hydroponic system is an unsuitability for
the testing of container stock because of failure
to adequately aerate the root balls.

The aeroponic system includes the use of mist
boxes or chambers in which the seedling root
systems are suspended (Day 1982, Hileman 1986). A
28-day test period has been used with Pistacia
chinensis (Lee and Hackett 1976), but Tinus et al .
(1986) have successfully shortened the test to 14
days with conifers by using a warm water mist to
accelerate root growth. The aeroponic system has
all the desirable characteristics of hydroponics
plus some important additional advantages.
Seedlings in mist chambers initiate new roots 1
week sooner than potted seedlings (Rietveld 1986)
and produce greater numbers of regenerating roots
than seedlings in concurrent pot tests (Lee and
Hackett 1976). This permits shorter test periods.
In addition, the aeroponically-created root
environment maintains xylem water potentials
similar to those of potted seedlings (Rietveld
1986) and is ideal for the testing of container
stock (Tinus et al. 1986). The aeroponic system
is rapidly becoming the method of choice for these
reasons. USDA Forest Service initiated aeroponic
RGP testing at all 11 of its nurseries in 1987.

The most desirable parameter of root growth
is total new root surface area, because it is
proportional to water and nutrient uptake ability
(Newman 1966). However, root surface area is not
readily measured. Thus, RGP is usually quantified
as total length and/or total number of new roots
per seedling (Ritchie 1984) . Total new root
length is directly proportional to surface area,
if, as assumed, the new roots are nearly all the
same diameter. If it is further assumed that most
new roots are the same length when root growth is
measured after a limited period of time, such as
14 or 28 days, then number of new roots will be
strongly correlated to new root length, and thus
to new root surface area also. Number and length
of roots are the consequence of different
processes, however. Number of roots per seedling
is a measure of the initiation of new roots and
the initiation of renewed growth of existing roots
(Stone et al . 1963). Total length of new roots
produced measures both initiation and elongation
(Ritchie and Dunlap 1980) . Root initiation and
elongation are controlled by different mechanisms
(Torrey 1976) , and respond differently to factors
such as chilling hours (Krugman and Stone 1966) ,
soil temperature (Nambiar et al . 1979), and
nutrient status (Nambiar 1980). Thus, it should
not be assumed that number and length of roots
will always be strongly correlated under all RGP
test conditions.

Total length and number of new roots per
seedling are thought to be fairly well correlated
using the standard pot test (Ritchie 1985) . Total
number of new roots (SO. 5 cm in length) was
correlated (R=0.8667) with total length of those
new roots in Pinus taeda using a 28-day got test
with an average root temperature of 26.5 C (Larsen
and Boyer 1986) . When RGP was measured as total
number of new roots 21.25 cm and as total length
of new roots 22.5 cm with a 30-day pot test and

20 C root temperatures, the two approaches gave
similar results (Krugman and Stone 1966) . This
type of data has led to the prevalent procedure of
measuring only total number of roots per seedling
because of the considerable reduction in the time
required to count the roots as opposed to
measuring root length (Ritchie 1985) . Similar
information on the correlation between length and
number of roots is unavailable for the aeroponic
method and shorter test periods.

A seedling quality test should, ideally,
provide the highest quality information, in the
shortest possible time, in the most efficient
manner, and for the widest range of stock types.
Toward this ideal with the RGP test, the
objectives of this study were to examine the
quality of information provided by 7-day vs 14-day
aeroponic tests of container stock from bud set to
bud break, with root growth quantified as total
length of new roots per seedling vs total number
of new roots per seedling. This research was
performed within the context of a larger study
examining the relationship between root growth
potential and two other seedling quality
parameters: cold hardiness and bud dormancy.

MATERIALS AND METHODS

Seedlings of ponderosa pine (Pinus ponderosa
var . scopulorum Engelm., Chevelon District,
Apache-Sitgreaves National Forests, elev. 2,300
m) , Douglas-fir (Pseudotsuga menziesii var. glauca
(Beissn.) Franco, Cloudcroft District, Lincoln
National Forest, elev, 2,700 m) , and Engelmann
spruce (Picea engelmannii (Parry) Engelm.,
Springerville District, Apache-Sitgreaves National
Forests, elev. 3,000 m) were greenhouse-grown in
400-ml Rootrainer^ book containers in a
peat-vermiculite mix for 9 months (October 1984 -
June 24, 1985). Greenhouse temperatures ranged
from 23 to 28°C daily (average 25°C) and 18 to

21 C at night (average 20 C) . Daylength was
extended to 22 hours with fluorescent light.
Other cultural conditions were as recommended by
Tinus and McDonald (1979). During the ninth
month, the trees set bud and entered dormancy.
The seedlings were then graded and those of
uniform size were placed in Percival HL-60 growth
chambers for a 4-stage, 19-week cold acclimation
and deacclimation regime (table 1) . Sodium and
multivapor arc lights provided 43,000 lux, and
watering was as needed with nutrient solution. At
approximately weekly intervals, a sample of 20
seedlings per species was taken for concurrent
tests of cold hardiness and root growth potential.

Whole-Plant Freeze Test

Cold hardiness was measured by a whole-plant
freeze test. One book of four seedlings of each

^Trade names are used for brevity and
specificity and do not imply endorsement by USDA
or Colorado State University to the exclusion of
other equally suitable products.

Table 1. — Cold acclimation and deacclimation
conditions .

Stage Day Dur-
nos . ation
(wks)

Day
temp .
(°C)

Night
temp .

(°C)

Day

length

(hrs)

Nutri-
ent
Solu-
tion

1 0-21 3

low N ,
high PK

2 22-71 7

low N
high PK

3 72-105 5

-3

low N
high PK

4 106-133 A

high N

species was placed in each of three styrofoam
coolers with the rootballs supported and covered
to a depth of 5 cm with dry vermiculite. The
coolers, with the lids wired shut and fitted with
thermister probes into the crowns of the
seedlings, were placed in a 650-liter household
chest freezer. Crown temgerature was lowered
rapidly from ambient to 0 C and at a rate of 3 to
5 C per hour thereafter. A baking pan filled with
liquid nitrogen was placed in the freezer to reach
temperatures below -25 C. The pan size and degree
of foam insulation controlled the rate of
temperature fall. Three temperatures, 5 C apart,
were selected to bracket the expected LTcq of the
stem tissue. When a cooler reached a selected
test temperature, it was removed from the freezer
and placed in a refrigerator at 1 C to thaw
overnight. The seedlings were then removed from
the coolers and placed in a warm greenhouse (day
26°C, night 19°C, 22-hour day).

Extent of injury to each seedling was
assessed after 7 days. The percentage of the
length of the stem that was killed was estimated
by examining the cambium and phloem for browning
and loss of tissue integrity. Rates of increasing
Injury with decreasing temperature were compared
across test day and species, and data with similar
rates were subjectively placed into six groups.
This pooling of data was necessary because 12
trees per species per test day did not provide
adequate information for statistical analysis.
Injury in the range of 10 to 90% was regressed
against temperature for each group, and the 50%
injury point (LT ) was estimated by calibration
methods (Graybill 1976) . The range 10 to 90% was
chosen because the relation between injury and
temperature was primarily linear, but nonlinear
above and below that range.

Root Growth Potential (RGP)

Eight additional seedlings per species were
placed in an aeroponic mist box in a greenhouse
(day 26 C, night 18 C, long days) to measure RGP.
A mist box measuring 1.0 m wide x 2.4 m long x 0.6
m high, was constructed of 5 cm thick rigid
urethane foam, and was fitted with a PVC piping,
3-nozzle system 25 cm above the floor of the box.
The seedlings were inserted through holes in

strips of plywood which formed the top of the box,
and were held in place with soft urethane foam
plugs. The intact rootballs, suspended within the
box, were exposed to 100% relative humidity at
27 C maintained by a warm-water intermittent mist.
After 7 and 14 days, the total number of new white
roots, SO. 5 cm in length, that had emerged from
the rootball were measured to the nearest cm and
counted. Tallied roots were marked with tempera
paint to prevent duplicate measurement. (The
paint was subsequently removed by the mist.)
Seedling height and caliper data were also taken.
Measurements were made without damage to the
seedlings, which were kept in the mist chamber
until bud break to assess dormancy status.

RGP was expressed as total number of new
roots per seedling and total length of new roots
per seedling, at 7 and 14 days. The data sets for
total new root length per seedling at 14 days for
the three species were selected to assess the
significance of possible covariates. There was no
trend over time in seedling height or caliper in
any of the three species. No consistent covari-
ance existed between RGP and height, caliper, or
(height X caliper ) in Engelmann spruce and
ponderosa pine. Seedling height was a significant
(p=.02) covariate in Douglas-fir, but the
contribution of the covariate was so small
(R =.04) that it did not warrant inclusion in
further data analysis. There was no consistent
covaria^ce between RGP and caliper or (height x
caliper ) in Douglas-fir.

Box plots were used to flag outliers in the
same three data sets (Chambers et al. 1983).
Thirteen of the 360 seedlings, with RGP measure-
ments several standard deviations from the weekly
mean, were omitted after each seedling was found
to be defective in some way, and therefore not
properly part of the main population. Weekly
means, with 95% confidence intervals, were calcu-
lated from the remaining observations for all 12
RGP data sets.

Homogeneity of variances was rejected
(pS.005) for all data sets using Bartlett's test.
Welch's test was used for comparing all means
within each data set because the data were not
suitable for transformation. All hypotheses of
equal means were rejected (p<.0001). Pairwise
comparison of means with an F-protected LSD test,
approximated using heterogeneous variance t-tests,
resulted in many statistically significant
differences (p=.05). However, because of the
heterogeneous variances, detecting differences
between means was not as straight forward as
applying a standard least significant difference
for all pairs compared. Thus, for ease of
interpretation, major differences between means,
as determined by the test of non-overlapping 95%
confidence intervals (Jones 1984) , were
established and indicated on Figures 2, 3, and 4.
The test of non-overlapping 95% confidence
intervals was found to be intermediate between the
more conservative Dunnett's T3 test (p=.05)
(Dunnett 1980) and the more liberal F-protected
LSD (p=.05). More Importantly, the chosen method
identified significant changes in RGP which could
be readily envisioned as biologically important

differences. Means with 95% confidence intervals
for the 12 data sets are presented in Burr (1987).

A correlation analysis between length and
number was performed for both 7- and lA-day data,
on an individual seedling basis within each
species, to determine how well total number of new
roots per seedling might indicate total length of
new roots per seedling.

RESULTS

Whole-plant Freeze Test

Maximum stem cold hardiness, expressed as an LT^^,
reached -35 C in ponderosa pine and -49 C in
Douglas-fir. Engelmann spruce cold hardiness on
test days 98 and 105 is indicated by asterisks at
-80 C (fig. 1). On these two days there was no
injury (LT ) to stem tissue at -75 C, the lower
limit of the freezer. Deacclimation began
immediately in all three species upon exposure to
the fourth stage conditions (day 22°C, night 22 C,
16-hour day) . Cold hardiness was rapidly lost and
reached minimum levels on test day 133 at the end
of the 19 weeks. Stem tissue cold hardiness on
test day 133 was -13 C in ponderosa pine and
-11.5 C in Douglas-fir and Engelmann spruce.

Cold hardiness was gained and lost in
response to the four successive temperature stages
(fig. 1). Seedlings of the three species did not
harden during the first stage with warn
temperatures and short days (day 20 C, night 15 C,
10-hour day). Stem cold hardiness, expressed as
an I'T^Q, ranged from -11 to -17 C for the three
species during these first 21 days. When growth
chamber temperatures were lowered to 10 C day and
3 C night in the second stage, there was a lag
period of variable length, depending upon the
species, before cold hardening of stem tissue
proceeded. There was a 1-week lag (test days 21
to 28) in ponderosa pine, a 2-week lag (test days
21 to 35) in Engelmann spruce, and a 2-week lag
after the first week of the second stage (test
days 28 to 42) in Douglas-fir. Cold hardiness
Increased after these lag periods until maximum
cold hardiness was reached at the end of the third
stage (day 5°C, night -3°C) on test day 105.

Stems

-5

-25 -

-45 -

a; -65 -

-85

SD5/N-3

57 88
Time (days)

119

150

Figure 1. — Stem cold hardin
pine (FP) , Douglas-fir
spruce (ES) as a funct
by the whole-plant fre
spruce cold hardiness
is indicated by asteri
two test days there wa
stem tissue at -75 C,
freezer. Growth chambe
indicated across the b
are described in table

ess (LT^q) of ponderosa

(DF) , and Engelmann
ion of time, determined
eze test. Engelmann
on test days 98 and 105
sks at -80 C. On these
s no injury (LT^) to
the lower limit of the
r conditions are
ottom of the graph and
1.

Bud Dormancy

Dormancy requirements for ponderosa pine were
fully met by test day 21, at the end of the first
stage, and for both Douglas-fir and Engelmann
spruce by test day 71, at the end of the second
stage. Bud break occurred during the 18th week of
the regime in Engelmann spruce, and during the
19th week in ponderosa pine and Douglas-fir.

Root Growth Potential (RGP)

The RGP patterns were similar, in a general
way, for the three species, whether measured as
total length or total number of new roots per
seedling, after either 7 or 14 days in the mist
chamber (figs. 2, 3, 4). RGP was low in the first
stage when cold hardiness was at a minimum and
dormancy intensity was maximum. RGP remained low
for differing portions of the second stage. High,
though variable, RGP levels were reached in the
second and/or third stages as cold hardiness
increased and chilling requirements for bud
dormancy were met. Maximum RGP levels were at
least 5-fold greater than minimum RGP levels.
During the first week of deacclimation in the
fourth stage, RGP did not decrease, although
approximately 65% of maximum cold hardiness was
lost. Following the first week of deacclimation,
RGP declined rapidly. Both cold hardiness and RGP
had returned to minimum levels at bud break.

Correlation analysis within each species
indicated that total length and total number of
new roots at 7 days were strongly correlated
(R=.918 to .933), as were total length and total
number of new roots at 14 days (R=.889 to .948)
(table 2). The strength of the correlation
between length and number at 7 days was similar to
that at 14 days in Douglas-fir and Engelmann
spruce. In ponderosa pine, the correlation
between length and number was stronger at 7 days
than after 14 days. The variability in total
number of new roots per seedling accounted for
79.0 to 89.9% of the variability in total new root
length per seedling, depending upon species and
time of measurement. The patterns of the RGP
means, expressed as total length and total number
of new roots at each of the two measurement times,
were thus very similar within each species (figs.
2, 3, 4).

In general, for the three species, changes as
large or larger than a 100% increase or decrease

Table 2. — Correlation analysis between total
length and total number of new roots per
seedling for each species after 7 and 14
days in the mist chamber.

Species

Ponderosa pine

7 days

.93330

.87105

14 days

.88901

.79034

Douglas-fir

7 days

.92333

.85255

14 days

.94828

.89924

Engelmann spruce

7 days

.91811

.84293

14 days

.90630

82138

(e.g. doubling) in RGP over time were
significantly different, independent of time or
method of measurement. Changes in number or
length of roots during the 19-week regime were not
statistically significant on the same test date
when measured at 7 and 14 days. When ponderosa
pine RGP was measured as total new root length per
seedling (fig. 2k), the first significant increase
in RGP during cold acclimation occurred on test
day 42 when measured at 14 days, and on test day
56 when measured at 7 days . The decrease in RGP
during the third stage was not significantly
different from the peak on test day 71 when
measured at either time. However, the low RGP
levels in the third stage were not significantly
different from the earlier low levels, such as
between test days 14 and 28. RGP increased on
test day 112, after 1 week of deacclimation , when
measured at both times, but the increase was
significant only at 7 days. RGP then returned to
the original low levels. When ponderosa pine RGP
was measured as total number of new roots per
seedling (fig. 2B) , the first significant increase
in RGP during cold acclimation also occurred on
test day 42 when measured at 14 days, and on test
day 56 when measured at 7 days. The decrease in
RGP during the third stage was significantly lower
than the peak on test day 71 but also
significantly greater than the earlier lowest (a)
levels, when measured at both 7 and 14 days. The
increase in RGP during the first week of
deacclimation was significant only when measured
at 7 days. RGP then returned to the original low
levels .

In Douglas-fir, when RGP was measured as
total length or number of new roots per seedling
(figs. 3A, 3B) , the first significant increase in
RGP during cold acclimation occurred on test day
42 when measured at 14 days, and on test day 71
when measured at 7 days. A second significant
increase occurred in both the 7- and 14-day
measurements by test day 84. This was followed by
a significant decrease in RGP on test day 98, when
measured at 7 days, which was not significantly
different from the earlier lowest (a) levels.
The pattern was not the same at 14 days. The
changes in RGP during the first week of

deacclimation were not significant at either
measurement time, and by the end of the fourth
stage, RGP had returned to the earlier lowest
levels .

When Engelmann spruce RGP was measured as
total length or number of new roots per seedling
(figs. 4A, 4B) , the first significant increase
during cold acclimation occurred on test day
42 when measured at 14 days, but did not occur
until test day 84 when measured at 7 days. RGP
fluctuated from test day 42 to the end of the
third stage, on test day 105, when measured at 14
days, though none of the changes were

A. Ponderosa Pine

600

500

400

300

- 200

100

57 88
Time (days)

B Ponderosa Pine

119 1 50

250

200

150

100-

57 88
Time (days)

Figure 2. — Ponderosa pine root growth potential
expressed as (A) total length of new roots
per seedling and (B) total number of new
roots per seedling measured after 7 or 14
days in a mist chamber, as a function of
time. Within each curve (7 days and 14
days) , means with the same letter are not
significantly different. Growth chamber
conditions are Indicated across the top of
the graphs and are described in table 1 .

150

statistically significant. There was also no
further significant change in RGP during the third
stage when measured at 7 days. None of the
changes in RGP during the first week of
deacclimation were significant when measured after
either 7 or 14 days. RGP had returned to fairly
low levels at the end of the fourth stage.

Ponderosa pine data were normalized to test
day 71, and Douglas-fir and Engelmann spruce data
to test day 84, to illustrate the differences and
similarities in the patterns of the 7- and 14-day

measurements (figs. 5, 6, 7). The normalized
ponderosa pine data (fig. 5) made more apparent
the 2-week delay in detecting the increase in RGP
during cold acclimation when RGP was measured
after 7 days. Measurement of total number of new
roots per seedling at 14 days best differentiated
between the low RGP levels of the third stage and
of the first two stages. The increase in RGP
during the first week of deacclimation was readily
detected when measurements were made after 7 days.

A Douglas-fir

A. Engelmann Spruce

1 4 Days

150

600

E 500

03 400

300

^ 200

o 100

SD10/N3 SD5'N-3 LD22/N22

1 4 Days

Time (days)

57 88
Time (days)

150

B Douglas-fir

B, Engelmann Spruce

250

e 200

150

100

14 Days

57 88 119 150

Time (days)

Figure 3. — Douglas-fir root growth potential

expressed as (A) total length of new roots
per seedling and (B) total number of new
roots per seedling measured after 7 or 14
days in a mist chamber, as a function of
time. Within each curve (7 days and 14
days) , means with the same letter are not
significantly different. Growth chamber
conditions are indicated across the top of
the graphs and are described in table 1 .

250

E 200

150

100

1 4 Days c

57 88
Time (days)

150

Figure 4. — Engelmann spruce root growth potential
expressed as (A) total length of new roots
per seedling and (B) total number of new
roots per seedling measured after 7 or 14
days in a mist chamber, as a function of
time. Within each cruve (7 days and 14
days) , means with the same letter are not
significantly different. Growth chamber
conditions are indicated across the top of
the graphs and are described in table 1.

The normalized Douglas-fir RGP data (fig. 6)
made more apparent the 4-week delay in detecting
the increase in RGP during cold acclimation when
measured at 7 days. Also apparent was the
inability to distinguish the low RGP on test day
98 from the RGP prior to test day 42, when
measured at 7 days. When measured at 14 days, the
decline on test day 98 indicated a fluctuation
during a period of high RGP, rather than a sudden
loss of RGP. During the first week of
deacclimation , 7-day measurements suggested an
increase in RGP more strongly than 14-day
measurements .

increase in sample size from 8 to 32 would reduce
the size of the confidence interval by 56% and a
44% increase or decrease in RGP would be
significantly different.

A significant increase in RGP during cold
acclimation was detected 2 to 6 weeks earlier in
the three species when RGP was measured after 14
days, rather than after 7 days, regardless of
whether root number or length was measured. The
inability to detect the increase when measured at
7 days was apparently the result of low growth

Normalized Engelmann spruce RGP data (fig. 7)
indicated that detection of a significant increase
in RGP above the low levels prior to cold
acclimation in the second stage required an
additional 5 to 6 weeks when measured at 7 days.
During the first week of deacclimation, 7-day
measurements suggested an increase in RGP, while
14-day measurements indicated no change.

DISCUSSIONS AND CONCLUSIONS

The RGP patterns of the three species (figs.
2, 3, 4) were a function of seedling response to
simulated seasonal environmental changes created
in growth chambers. Nevertheless, these patterns
were quite representative of RGP patterns reported
in the literature for nursery-grown bareroot
seedlings lifted at regular intervals from bud set
to bud break (Jenklnson 1980, Ritchie and Dunlap
1980, Stone et al. 1962) .

RGP's measured as total number and as total
length of new roots per seedling were strongly
correlated in all three species, whether measured
after 7 or 14 days in the mist chamber (table 2) .
Number of roots was a good predictor of length,
indicating that changes over time in total new
root length were mainly the result of changes in
the number of roots elongating rather than changes
in the elongation rate of the individual r^ots.
Rietveld (1986) fou^d that total number (R =.88)
and total length (R =.90) of new roots were
strongly correlated to a root area index, using a
17-day aeroponic test. Thus, not only were number
and length of new roots well correlated, but both
were also good estimators of new root surface
area, the parameter of primary interest. Since
length and number were nearly equally informative
under the test conditions used here, measuring
total number of new roots is recommended because
it required only 25% of the time necessary to
measure total new root length. More information
can thus be gained per unit of time spent in data
collection by measuring only the number of new
roots on a 4-fold larger sample of seedlings than
by also measuring total new root length on a 75%
smaller sample of seedlings. For example, using
the test of non-overlapping 95% confidence
intervals, a doubling of the sample size from 8 to
16 seedlings would reduce the size of the
confidence interval by 35%. Since a change in RGP
of approximately 100% was required to be
significantly different with a sample size of 8, a
65% increase or decrease would be significantly
different with a sample size of 16. A 4-fold

A Ponderosa Pine

800

700

- 600

^ 500

400

^ 300

200

100

SD20 N15

1 1

SOlO N3

SD5 N-3

t LD22 N22

1 1
I 1

250

1 <
I 1
1 1
1 1
1 1

1 I
1 1

200

1 4 Days /

150

1 •

'7 \* *

100

^ V

- \ 1 /'' Days

1 1

26 57

119 1 50

Time (days)

B Ponderosa Pine

250

- 200

150

100

SD20/N15

1 1

SD10 N3

S05'N-3

^ LD22/N22

1 4 Days/ /
1 f

• / /7 Days

*' v

1 1

150

125

100

57 88
Time (days)

119

150

Figure 5. — Ponderosa pine root growth potential
expressed as (A) total length of new roots
per seedling and (B) total number of new
roots per seedling measured after 7 to 14
days in a mist chamber, as a function of
time. The 7-day Y-axis scales have been
adjusted such that the 7- and 14-day data
converge at test day 71. Growth chamber
conditions are indicated across the top of
the graphs and are described in table 1 .

levels during the first 7 days in the mist chamber
combined with high levels of growth during the
second 7 days (figs. 2, 3, 4). A second
disadvantage of 7-day measurement of RGP during
the period of cold acclimation was the inability
to distinguish between fluctuations in high RGP
levels and the low RGP levels prior to the start
of cold acclimation. This was particularly true
in Douglas-fir (fig. 3) and also in ponderosa pine
(fig. 2k). Additionally, all first significant
increases in RGP, when measured after 14 days in
the mist chamber, occurred on test day 42, whether
expressed as total number or total length of new
^roots. The increase in RGP between test days 35
and 42 corresponded well with the onset of steady,
rapid increases in cold hardiness (fig. 1) . It
marked the end of the plateau period at the

beginning of the second stage, during which there
was a lag in the development of cold hardiness as
well as RGP. No such relationship was apparent
between cold hardiness and RGP measured at 7 days.
Measurement of RGP after 7 days was not as
informative as measurement at 14 days during the
period of cold acclimation for these reasons. A
7-day test of RGP prior to cold deacclimation ,
whether as a routine test of seedling quality or
over a period of time to determine lifting
windows, could be very misleading.

However, measurement of RGP after 7 days may
be a better indicator of the onset of
deacclimation than 14-day measurement, especially
in ponderosa pine (fig. 5). For example, RGP
consistently increased during the first week of

A Douglas-fir

A. Engelmann Spruce

- 200 «

150 ^

250

100

- 50

119 1 50

600

- 500

^ 400

300

13, 200

100

SD20/N15

1 1

SD10/N3

SD5/N-3

LD22/N22

' \

I M '

/ \ 1 ' ^ —

1 4 Days/^\

/' \ ~»-r* V \

/'' \ / *

y\*h. /l Days
1 1

- 200

150

100

50 :i

119

150

Time (days)

B. Douglas-fir

B Engelmann Spruce

14 Days

150 a

100

50 s

57 88
Time (days)

150

250

- 200

150

S 100

1 1

SD20/N15

SD10/N3

SD5/N-3

LD22/N22

14 Days/ ^\

// Y-^>

\ ';

V •

/ \ j( /7 Days

1 1

57 88
Time (days)

119

150

Figure 6. — Douglas-fir root growth potential

expressed as (A) total length of new roots
per seedling and (B) total amount of new
roots per seedling measured after 7 or 14
days in a mist chamber, as a function of
time. The 7-day Y-axis scales have been
adjusted such that the 7- and 14-day data
converge at test day 84. Growth chamber
conditions are indicated across the top of
the graphs and are described in table 1 .

Figure 7. — Engelmann spruce root growth potential
expressed as (A) total length of new roots
per seedling and (B) total number of new
roots per seedling measured after 7 or 14
days in a mist chamber, as a function of
time. The 7-day Y-axis scales have been
adjusted such that the 7- and 14-day data
converge at test day 84. Growth chamber
conditions are indicated across the top of
the graphs and are described in table 1.

deacclimat Ion when measured after 7 days. Though
the increase was significant only in ponderosa
pine (fig. 2), the normalized data (figs. 5, 6, 7)
indicated that the relative magnitude of the
increase was greater at 7 days than at 14 days in
all instances. RGP measurement at 14 days during
the first week of deacclimation led to the
conclusion that no change occurred. The rapid
decline in RGP after the first week of
deacclimation was as clearly indicated in the
7-day measurements as in the 14-day measurements
(figs. 5, 6, 7). This was true largely because
the majority of the root growth, especially
increases in number of roots, occurred during the
first 7 days in the mist chamber. RGP
measurements at 7 days are thus recommended if the
data are to be used to monitor the rapid loss of
stock quality with approaching bud break.

In summary, total length and total number of
new roots per seedling were nearly equally
informative with container stock under the mist
chamber conditions described. Use of number of
roots with relatively larger sample sizes is
recommended as most efficient and informative.
RGP tests of 7 and 14 days in duration yielded
different information. On the basis of accuracy
and quantity of information provided, the 14-day
test is recommended during cold acclimation and
the 7-day test is suggested for use during cold
deacclimation .

LITERATURE CITED

Burdett, A. N. 1979. New methods for measuring
root growth capacity: their value in
assessing lodgepole pine stock quality. Can.
J. For. Res. 9:63-67.

Burdett, A. N., D. G. Simpson, and C. F. Thompson.
1983. Root development and plantation
establishment success. Plant and Soil
71:103-110.

Burr, K. E. 1987. Cold hardiness, root growth

capacity, and bud dormancy testing of conifer
seedlings. Ph.D. Dissertation, Colorado State
University, Fort Collins, Colo., p. 109-115.

Chambers, J. M., W. S. Cleveland, B. Kleiner, and
P. A. Tukey. 1983. Graphical methods for
data analysis. Wadsworth Internat. Group,
CA. 395p.

Day, R. J. 1982. Evaluating root regeneration
potential of bare-root nursery stock, p.
83-96 In: Huber, R. F., compiler. Proc . 1981
Intermountain Nurser5rmen ' s Assoc. meeting,
Aug. 11-13, 1981, Edmonton, Alberta.
Environ. Can., For. Serv., North. For. Res.
Cent., Edmonton, Alberta. Inf. Rep.
NOR-X-241.

DeWald, L. E., P. P. Feret, and R. E. Kreh. 1985.
A 15-day hydroponic system for measuring root
growth potential. U.S.D.A. For. Serv. Gen.
Tech. Rep. SO-54, p. 4-10.

Dunnett, C. W. 1980. Pairwise multiple

comparisons in the unequal variance case. J.
Amer. Statistical Assoc. 75:756-800.

Graybill, F. A. 1976. Theory and application of

the linear model. Section 8.5. Duxbury

Press, CA. 704 p.
Hileman, G. R. 1986. Root growth capacity

system. U.S.D.A. For. Serv. Gen. Tech. Rep.

RM-137, p. 75-76.
Jenkinson, J. L. 1980. Improving plantation

establishment by optimizing growth capacity

and planting time of western yellow pines.

U.S.D.A, For. Serv. Res. Pap, PSW-154, 22p,
Jones, D. 1984. Use, misuse, and role of

multiple-comparison procedures in ecological

and agricultural entomology. Environ.

Entomol. 13:635-649.
Krugman, S. L. and E. C. Stone. 1966. The effect

of cold nights on the root-regenerating

potential of ponderosa pine seedlings. For.

Sci. 12:451-459.
Larsen, H. S. and J. N. Boyer. 1986. Root growth

potential of loblolly pine (Pinus taeda L.)

seedlings from twenty southern nurseries.

Circular 286, Ala. Agric. Exp. Stn., Auburn

Univ. 16p.
Lee, C. I. and W. P, Hackett, 1976. Root

regeneration of transplanted Pistacia

chinensis Bunge seedlings at different growth

states, J. Amer. Soc. Hort . Sci.

101:236-240.
Nambiar, E. K. S., G. D. Bowen, and R. Sands.

1979. Root regeneration and plant water

status of Pinus radiata D. Don seedlings

transplanted to different soil temperatures.

J. Exp. Bot. 30:1119-1131.
Nambiar, E. K. S. 1980. Root configuration and

root regeneration in Pinus radiata seedlings.

N.Z. J. For. Sci. 10(1) :249-263.
Newman, E. I. 1966. A method of estimating the

total length of root in a sample. J. Appl,

Ecol, 3:139-145.
Rietveld, W. J. 1986. A new, more efficient

method to evaluate root growth potential of

planting stock using a root area index.

U.S.D.A, For, Serv, Gen, Tech, Rep, RM-137,

p. 96.

Ritchie, G. A. and J. R. Dunlap. 1980. Root
growth potential: its development and
expression in forest tree seedlings. N.Z. J.
For. Sci. 10(1) :218-248.

Ritchie, G. A, 1984, Assessing seedling quality.
Ch. 23 In: Duryea, M, L, and T, D, Landis,
eds. Forest nursery manual: Production of
bare-root seedlings. Martinus Nijhoff/Dr, W.
Junk Pub., The Hague/Boston/Lancaster. 386p.

Ritchie, G. A. 1985. Root growth potential:
principles, procedures, and predictive
ability. Ch. 8 In: Duryea, M. L. ed .
Evaluating seedling quality: principles,
procedures, and predictive abilities of major
tests. Workshop held October 16-18, 1984.
Forest Research Laboratory, Oregon State
University, Corvallis. 143p.

Rose, R. W, and R, P, Whiles, 1985, Root growth
potential and carbohydrate shifts in
previously cold stored loblolly pine
seedlings grown in hydroponic culture.
U.S.D.A. For. Serv. Gen. Tech. Rep. SO-54, p.
25-33.

Stone, E, C. 1955. Poor survival and the

physiological condition of planting stock.
For. Sci. 1:90-94.

Stone E. C, E. E. Gilden, D. W. Cooper, and R. J.
Malain. 1961. Planting dates for
Douglas-fir seedlings in California forest
lands. Calif. Agric. 15(8):15-16.

Stone, E. C. and J. L. Jenkinson. 1970.

Influence of soil water on root growth
capacity of ponderosa pine transplants. For.
Sci. 16:230-239.

Stone, E. C, J. L. Jenkinson, and S. L. Krugman.
1962. Root-regenerating potential of
Douglas-fir seedlings lifted at different
times of the year. For. Sci. 8:288-297.

Stone, E. C. and G. H. Schubert. 1959. Root
regeneration by ponderosa pine seedlings
lifted at different times of the year. For.
Sci. 5:322-332.

Stone, E. C, G. H. Schubert, R. W. Benseler,
F. J. Baron, and S. L. Krugman. 1963.
Variation in the root regenerating potentials
of ponderosa pine from four California
nurseries. For. Sci. 9:217-225.

Sutton, R. F. 1980. Planting stock quality, root
growth capacity, and field performance of
three boreal conifers. N.Z. J. For. Sci.
10(1) :54-71.

Tinus, R. W., K. E. Burr, S. J. Wallner, and

R. M. King. 1986. Relation between cold
hardiness, root growth capacity, and bud
dormancy in three western conifers. U.S.D.A.
For. Serv. Gen. Tech. Rep. RM-137, p. 80-86.

Tinus, R. W. and S. E. McDonald. 1979. How to
grow tree seedlings in containers in
greenhouses. U.S.D.A. For. Serv. Gen. Tech.
Rep. RM-60. 256p.

Torrey, J. G. 1976. Root hormones and plant

growth. Ann. Rev. Plant Physiol. 27:435-459.

Winjum, J. K. 1963. Effects of lifting date and
storage on 2+0 Douglas-fir and noble fir. J.
For. 61:648-654.

Effects of Lift Date, Storage, and Family on Early
Survival and Root Growth Potential of Shortleaf Pine^

S. W. Hallgren and C. G. Tauer^

Abstract. — High survival and RGP can be
expected for seedlings planted from December
through February even when a severe spring drought
occurs. Seedling performance is only slightly
reduced by storage, is positively related to
number of primary lateral roots, negatively
related to presence of secondary needles, and not
related to the presence of a terminal bud.

INTRODUCTION

Shortleaf pine (Pinus echinata Mill.)
is the most widespread of the southern
pines. It is an important timber species,
and is widely planted by the U.S. Forest
Service and private industry. Current
nursery practices and regeneration
techniques that work well for loblolly
pine are apparently inappropriate for
shortleaf pine which shows very poor
survival in plantations in the Ozark and
Ouachita Mountains. Contributing to these
poor results is the lack of specific
information about artificial regeneration
of shortleaf pine (Barnett et al. 1986).

Previous research has led to the
recommendation that southern pine seedling
quality be assessed by grading seedlings
for planting. Results vary somewhat, but
in general best performance can be
expected from seedlings that are large and
have an appropriate root/shoot ratio, that
have a woody stem, secondary needles and a
terminal bud (Wakely 1954, Phares et al.
1960, Grigsby 1975, Barnett 1984, Barnett
et al. 1985). Shortleaf pine seedlings
grown in southwest Arkansas showed high
field survival when lifted and planted
immediately during December through
February. Only seedlings lifted in
December retained high survival rates
after cold storage for 3 0 days (Venator
1985) .

■^Paper presented at the Intermountain
Nursery Association Meeting [Oklahoma
City, August 10-14, 1987].
Professional paper No. P-2540 of the
Agricultural Experiment Station,
Oklahoma State University.

S. W. Hallgren is Assistant
Professor and C. G. Tauer is Professor of
Forestry at Oklahoma State University,
Stillwater.

The capacity of a seedling to rapidly
produce new roots when transplanted into
the field is critical for survival and
growth. A frequently used measure of this
capacity is root growth potential (RGP)
which is considered a valuable tool for
assessing seedling quality (Ritchie and
Dunlap 1980) . RGP can be measured by
growing seedlings in a controlled
environment for 4 weeks and counting the
number of new roots greater than 1 cm
long. Factors known to affect RGP are
genotype, nursery environment, lifting
dates, and storage (Ritchie and Dunlap
1980, Jenkinson and Nelson 1978, Carlson
1985) , but very little is known about RGP
in shortleaf pine.

This study was undertaken to develop
improved techniques for artificial
regeneration of shortleaf pine. Since
there is considerable interest in managing
seedlings by family we decided to evaluate
the genetic variability in effects of lift
date and storage on survival and growth.
In order to better understand treatment
response, seedlings were also measured for
size, number of primary lateral roots,
root growth potential and presence of
secondary needles and a terminal bud.

MATERIALS AND METHODS

Shortleaf pine seedlings of 12 open-
pollinated families from Oklahoma and
Arkansas were grown for one season under
operational procedures at the Weyerhauser
Company Nursery at Fort Towson, Oklahoma.
Seedlings were grown in 3 replicates in a
randomized complete block design. They
were operationally undercut at a depth of
15 cm in November 1986.

starting December 1, 1986, one fifth
of the seedlings in each replicate were
hand-lifted every 28 days for 5 lifts
until March 23, 1987 (Table 1).

Table 1. — Schedule of Lift and Plant
Activities

Lift

Plant

Not

Stored

Dec. 1

Dec.

Dec. 29

Dec.

Dec. 30

Jan. 26

Jan.

Jan. 27

Feb. 23

Feb.

Feb. 24

Mar. 2 3

Mar.

Mar. 24

Apr. 21

Following each lift seedlings were graded
according to operational standards and
divided into two equal groups, one for
immediate testing and one to be stored for
28 days and then tested. Each group was
divided a second time, 80 seedlings per
family going to the field planting and 24
to the RGP test. The integrity of nursery
replicates was maintained throughout the
study .

The field test was planted at the
Kiamichi Forest Research Station near
Idabel, Oklahoma. Seedlings were planted
one day after lifting or upon removal from
28 days of storage. The experimental
design was a 12 x 5 x 2 (family x lift
date X storage) factorial with 10
replicates laid out in randomized complete
block design. Each treatment combination
was represented by an 8-tree row plot in
each replicate. A total of 9600 trees
were planted at a spacing of 0.5 m and the
entire experiment was surrounded by a
border row of similar shortleaf pine
seedlings. Immediately after the last
planting, all the seedlings were measured
for survival, diameter and height.

Weeds were controlled by herbicides
and manual methods. No irrigation was
applied. Temperature and precipitation
were monitored at a weather station on the
center. Early survival was counted on
June 22, 1987. The experiment will be
monitored for survival and growth for two
years .

Seedlings for the RGP test were kept
in cold storage until the test began 3
days after lifting or the end of the cold
storage treatment. Prior to commencement
of the RGP test seedlings were measured
for height, diameter, number of primary
lateral roots, root volume and presence of
secondary needles and a terminal bud.

Three seedlings of a family were
planted into 1 1 milk carton pots filled
with a 1:1 peat-vermiculite mixture (on
the first test date, 2 1 cartons were
used) . The pots were arranged in a
randomized complete block design with 8
replicates. The test was conducted in a
controlled environment chamber set for a
16 hour photoperiod and a 25° C day/15° C
night. After 28 days the seedlings were
removed from the chamber and placed in
cold storage until the roots could be
washed and the new root tips longer than 1
cm counted. RGP measurement was complete
within 2 to 3 days.

The data were subjected to analysis
of variance to determine the significance
of family, lift date and storage on RGP
and seedling survival. Phenotypic
correlations between survival and the
various seedling traits were calculated.

RESULTS AND DISCUSSION

Lift date, storage and family all
showed a significant effect (P< 0.05) on
survival and RGP of shortleaf pine (Table
2) .

Table 2. — Analysis of Variance Results

Probability

> F

Source

Survival

RGP

Date (D)

<0.0001

<0. 0001

Storage (S)

<0. 0001

0. 0465

Family (F)

<0. 0001

<0.0001

D X S

<0. 0001

<0.0001

D X F

0.2765

<0.0001

S X F

0.7704

0.4405

D X S X F

0.0323

0.2512

Error

1071/833

A significant interaction of lift date
with storage suggested that seedling
performance after storage is dependent in
part on lifting date. The lack of an
interaction between family and lift date
and family and storage treatment for
survival indicates that in general the
families respond in a similar manner to
lift date and storage. However, a
significant three-way interaction between
lift date, family and storage treatment
suggests the survival response is complex.
In general, the families showed a
dissimilar RGP response to different lift
dates but a similar RGP response to
storage treatment.

These results correspond well with
previous work in pines that has shown lift
date to affect survival and RGP (Jenkinson
1975, Jenkinson and Nelson 1978). Lift
date is also known to determine the
response of seedlings to storage (Stone
and Jenkinson 1971, Venator 1985) . The
pattern of changes in RGP and survival
with time of lift as well as the magnitude
of RGP at a given date have been shown to
be under strong genetic control (Jenkinson
1975, Nambiar 1982, Carlson 1985 and
1986) .

Overall, survival was high, over 90
percent, for seedlings planted from early
December to late February whether they
were stored or not (Figure 1) . Survival
fell after February and the late March
planting showed survival of 80 and 85
percent for freshly lifted and stored
seedlings. Only stored seedlings were
planted in late April and survival was
poor, less than 50 percent.

Survival for a specific planting date
was generally reduced only 5 percent by
storage (Figure 1) . Seedlings lifted on a
given date showed a reduction in survival
due to storage of only 2 percent in
December, 8 to 10 percent in January and
February and 3 6 percent in March. The
March lifted seedlings planted in April
showed poor survival partly due to the
spring drought.

RGP followed a seasonal pattern
somewhat similar to that for survival,
showing high values of 80 to 110 new roots
for seedlings lifted in December, stored
and unstored, and in January, unstored
(Figure 2) . RGP fell to 50 to 75 new
roots for stored seedlings lifted in
January and all seedlings lifted after
January whether stored or unstored. The
stored seedlings tested in April showed a
higher RGP than seedlings tested in March
and yet they showed much lower survival in

100

■<

RVI

t—

stared

NOV DEC JAN

MAR
DATE

APR

MAY JUN JUL

Figure 1. Effect of lift date and storage
on June 22 survival of shortleaf pine
seedlings by planting date. Points
represent values averaged across 12
families and bars represent plus and
minus the standard error of the mean.

175

150

125

1—

ICQ

.1 ...--[ Stored

unstored

NOV DEC JAN FEB

MAR

DATE

APR MAY JUN JUL

Figure 2. Effect of lift date and storage
on root growth potential of shortleaf
pine seedlings by date tested.
Points represent values averaged
across 12 families and bars represent
plus and minus the standard error of
the mean.

The late season drop in survival can
be at least partially explained by the
weather at the planting site.
Temperatures were mild and precipitation
adequate from November 198 6 through March
1987. The weekly maximum temperatures
never exceeded 3 0°C and monthly rainfall
ranged from 45 mm in December to 164 mm in
March. April and early May were much
hotter and drier with weekly maximum
temperatures constantly above 3 3°C and
rainfall of only 9 mm from March 3 0 until
May 15. Temperatures remained high and
precipitation returned to higher levels
for the last 2 weeks of May (154 mm) and
the first 3 weeks of June (40 mm) .

the field. Apparently the higher RGP did
not prevent severe mortality for seedlings
planted in the middle of the spring
drought. It is worth noting that in
general RGP declined for seedlings lifted
in February and later at the same time
that risk of mortality from drought and
high temperature was increasing. The
effects of storage on RGP were generally
small and inconsistent from one lift date
to the next.

Comparison of survival across all
dates for families showing the highest
(Family 5) and lowest (Family 6) survival
reveals small differences for unstored

seedlings, usually less than 10 percent,
and much larger differences for stored
seedlings, usually 20 percent or greater
(Figure 3). These families showed similar
seasonal changes in survival and
maintained their respective ranks
regardless of storage treatment.

100
90

•<

RVI

Rn
ou

»—

ACi
*rU

CK
UJ

lOOi

80-

•<

70-

60-

t/1

50-

40-

□-

20-

NOV DEC JAN FEB

MAR
DATE

APR MAY JUN JUL

NOV DEC JAN FEB

MAR
DATE

APR MAY JUN JUL

Figure 3. Effect of lift date and storage
on June 22 survival of shortleaf pine
families showing the highest (Family
5) and lowest (Family 6) overall
survival. Data are plotted by date
planted for unstored (a) and stored
(b) seedlings. Bars represent plus
and minus the standard error of the
mean.

RGP showed a good relationship to
field survival, as high survival for
Family 5 was associated with high RGP and
low survival of Family 6 was associated
with low RGP across all dates regardless
of storage treatment (Figure 4) . Unstored
seedlings showed a peak RGP in early
December for Family 5 and late January for
Family 6. Stored seedlings showed a peak
RGP for both families in late January.

Survival was significantly correlated
to RGP and number of primary lateral roots

175

150

125

1/1

^—
o

100

NOV DEC JAN FEB MAR APR MAY JUN JUL
DATE

175

150

125

1/5

t—
O

100

NOV DEC JAN FEB

MAR
DATE

APR MAY JUN JUL

Figure 4. Effect of lift date and storage
on root growth potential of shortleaf
pine families showing highest (Family
5) and lowest (Family 6) overall
survival. Data are plotted by date
tested for unstored (a) and stored
(b) seedlings. Bars represent plus
and minus the standard error of the
mean.

(Table 3) . Previous research has often
shown a close relationship between RGP and
survival (Ritchie and Dunlap 1980, Nambiar
et al. 1982, Larsen et al. 1986). Other
root characteristics such as root weight
and shoot/root ratio may be correlated
with survival (Larsen et al. 1986), and
the importance of primary laterals in
development of RGP has been noted (Nambiar
et al . 1982). The current study clearly
shows the close relation between number of
primary laterals and survival. In fact,
it was a better predictor of survival than
RGP. Number of primary laterals is easier
to measure than RGP and should be given
consideration as a measure of seedling
quality.

Survival showed no correlation with
root volume, diameter and height (Table
3) . We observed that root volume appeared
to be largely determined by the tap root
size which was reflected in seedling
diameter, hence the close relation between

Table 3. — Phenotypic Correlations for Survival and Various
Seedling Traits

RGP ROOT ROOT DIA HGT BUD SECONDARY
VOL. NEEDLES

SURVIVAL .657* .709* .109 -.173 -.093 -.263 -.661*

RGP .900** ,527 .216 .126 -.268 -.299

ROOT .624* .290 .223 -.140 -.278

ROOT VOL. .842** .327 .353 .384

DIA. .614* .600* .620*

HEIGHT .384 .246

BUD

* Significant at 5% level
**Signif icant at 1% level

.707**

root volume and diameter. Apparently, the
number of primary lateral roots is more
important in determining survival than tap
root size.

Surprising was the fact that survival
was not related to the presence of a bud
and was negatively related to the presence
of secondary needles. The presence of
both a terminal bud and secondary needles
has been suggested as important to
seedling quality (Wakely 1954, Barnett et
al. 1986). The data from this study
indicates that this recommendation should
be reevaluated, at least for shortleaf
pine. Very little attention has been paid
to this species and it appears that
regeneration techniques developed for
other southern pines are not well suited
to it.

RGP was, not surprisingly, strongly
correlated to number of primary lateral
roots. This again reinforces the
suggestion that number of primary laterals
be considered as a measure of seedling
quality. RGP was not related to any of
the other seedling traits.

CONCLUSIONS

Early results show survival is high
for seedlings lifted from early December
through the end of February and planted
without storage. Seedlings lifted in
December and January can be stored for 28
days with only a slight reduction in
survival. Seedlings planted in March and
April are subject to greater mortality.
High RGP and number of primary lateral

roots are associated with high survival.
The presence of a terminal bud shows no
relation to survival, and the presence of
secondary needles appears to be negatively
related to survival. Family differences
in performance indicate a significant
opportunity to improve regeneration
techniques through management of seedlings
by family.

LITERATURE CITED

Barnett, J. P. 1984. Relating seedling
physiology to survival and growth in
container-grown southern pine. p.
157-176. In Seedling physiology and
reforestation success (M. S. Duryea
and G. N. Brown, eds.). Martinus
Nijhoff/Dr. W. Junk Pub., Boston.

Barnett, J. P., J. C. Brissette and W. C.
Carlson, 1985. Artificial
regeneration of shortleaf pine. p.
64-88. In Symposium on the shortleaf
pine ecosystem. [Little Rock, Ark.,
March 31-April 2, 1986] (P. A.
Murphy, ed.). Ark. Cooperative
Extension Ser. , Monticello, Ark.

Carlson, W. C. 1985. Effect of natural

chilling and cold storage on budbreak
and root growth potential of loblolly
pine. Can. J. For. Res. 15:651-656.

Carlson, W. C. 1986, Root system

considerations in the quality of
loblolly pine seedlings. South. J.
Appl. For. 10:87-92.

Grigsby, H. C. 1975. Performance of
large loblolly and shortleaf pine
seedlings after 9 to 12 years. USDA
Forest Service Res. Note 50-196, 4
p. Southern Forest Exp. Sta. , New
Orleans.

Jenkinson, J. L. 1976. Seasonal patterns
of root growth capacity in western
yellow pines, p. 445-453. In
Proceedings National Conv. Soc.
American. For. [Washington, D.C.,
Septeinber 28-October 2, 1975].
Society. Amer. Foresters.

Jenkinson, J. L. and J. A. Nelson. 1978.
Seed source lifting windows for
Douglas-fir in the Humbolt Nursery,
p. B77-B95. In Proceedings of the
western forest nursery council and
intermountain nurseryman's asso.
combined nurseryman ' s conf . and seed
processing workshop. [Eureka,
Calif., August 7-11, 1978]. USDA
Forest Service, Region 5, San
Francisco.

Larsen, H. S., D. B. South and J. M.

Boyer. 1986. Root growth potential,
seedling morphology and bud dormancy
correlate with survival of loblolly
pine seedlings planted in December in
Alabama. Tree Physiology 1:253-263.

Nambiar, E. K. S. and P. P. Cotterill.
1982. Genetic differences in the
root regeneration potential of
radiata pine, J. Exp. Bot. 33:170-
177.

Phares, R. E. and F. G. Liming. 1960.

Comparative development of seeded and
planted shortleaf pine on a forest
site in the Missouri Ozarks. Jour.
Forestry 58:957-959.

Ritchie, G. A. and J. R. Dunlap. 1980.
Root growth potential: its
development and expression in forest
tree seedlings. N.Z.J. For. Sci.
10:218-248.

Stone, E. C. and J. L. Jenkinson. 1971.
Physiological grades for ponderosa
pine nursery stock based on predicted
root growth capacity. J. For. 69:31-
33 .

Venator, C. R. 1985. Survival of

shortleaf pine fPinus echinata Mill.)
seedlings as influenced by nursery
handling and storage. Tree Planters'
Notes 36:17-19.

Wakely, P. C. 1954. Planting the

southern pines. USDA Forest Seirvice
Agricultural Monography 18. 233 pp.

Fall Lifting: Its Effects on Dormancy Intensity of
Ponderosa Pine Seedlings — A Preliminary Investigation^

Steven K. Omi and Ursula K. Schuch^

Abstract . --Initial assessment of the feasibility of
fall lifting ponderosa pine seedlings at Bend Pine Nursery,
Oregon, involved calculating fall chilling hours and
monitoring release of seedlings from dormancy. Seedlings
lifted earliest failed to break bud, whereas budbreak was
accelerated for trees lifted later in the fall. Results
suggest that chilling was required to release seedlings
from dormancy.

INTRODUCTION

Three basic lifting practices are available
for use in high elevation or latitude nurseries:
(Option 1) fall lift and plant, (Option 2) late
winter or spring lift and plant, and (Option 3)
fall lift, overwinter storage, and plant.
Disadvantages of Option 1 include risks that
early fall snows or drought will terminate the
planting operation (Tung et al. 1986) and that
stock will be lifted before it is physiologically
ready (Ritchie et al. 1985). Fall lifting date
is critical because of the potential to upset
natural phases of dormancy and release of
seedlings from dormancy.

A disadvantage of Option 2, the most common
practice in the Northwest, is that nursery soils
may remain frozen in the spring when sites are
ready for planting. In addition, seedlings left
in the ground during winter months may be exposed
to desiccating conditions and may be sensitive to
physiological stress at the end of the safe
lifting window (Ritchie and Dunlap 1980, Ritchie
et al. 1985).

Disadvantages of Option 3 include that of
Option 1 regarding fall lifting date. Further-

Ipaper presented at the Intermountain
Nursery Association Meeting. [Oklahoma City,
Okla., August 10-14, 1987].

^Steven K. Omi is a Graduate Research
Assistant, Nursery Technology Cooperative,
Department of Forest Science, Oregon State
University, Corvallis, Oreg. and USDA Forest
Service Cooperative Education Student, Bend Pine
Nursery, Deschutes National Forest. Ursula K.
Schuch is a former Graduate Research Assistant,
Nursery Technology Cooperative, Department of
Forest Science, Oregon State University,
Corvallis, Oreg.

more, storage can be unsuccessful if seedlings
are lifted prior to the period of deep dormancy,
when buds are not responsive to chilling (Stone
and Schubert 1959, Ritchie and Dunlap 1980).
Seedlings which are not at their fully dormant
stage have higher respiration rates (Hocking and
Ward 1972, Navratil 1973) and may deplete their
reserves faster during storage than do fully
dormant seedlings. Use of Option 3 has been
discouraged in the past (Hocking and Nyland 1971,
Hermann et al. 1972, Navratil 1973), based on
data primarily derived from research on mid- or
low-elevation conifer species (Tung et al.
1986). Recent studies, however, indicate that
fall lifting and long-term cold storage of high
elevation or latitude stock are feasible (Ritchie
et al. 1985, Tung et al. 1986).

Fall lifting and overwinter storage ensure
that stock is available when sites are ready for
planting. This practice alleviates winter losses
due to rodents, desiccating winds, or extreme
temperatures (Hocking and Nyland 1971). In
addition, it allows greater flexibility in the
workload and makes nursery areas available for
early cultivation (Hocking and Ward 1972, Mullin
and Bunting 1972, Hinesley 1982). Low
temperature storage of seedlings also can play a
role in satisfying chilling requirements (van den
Driessche 1977, Ritchie et al. 1985). The
relationship among lifting date, chilling hours,
and dormancy intensity for ponderosa pine is not
well known.

Bend Pine Nursery (Bend, Oreg.) is located
at an elevation of 3700 ft (1100 m) , where soils
can remain frozen in spring when lower elevation
forest sites are ready to plant. Fall lifting
has not been attempted recently at this nursery;
however, the practice of fall lifting and
overwinter storage is used for a variety of
conifer species at three USDA Forest Service
nurseries in the Northwest/Intermountain

region — Wind River Nursery (Carson, Wash.), Lucky
Peak Nursery (Boise, Idaho), and Couer d'Alene
Nursery (Idaho). These nurseries are similar to
Bend Pine Nursery in that their operations are
subject to winter snows and frozen soils.

A preliminary trial was initiated in fall
1986 to assess the feasibility of fall lifting at
Bend Pine Nursery. The objectives of the
investigation were to determine (1) the dormancy
status of fall-lifted trees and the preferred
chilling range for release of seedlings from
dormancy, and (2) the relationship between
cumulative chilling hours and budbreak.

To quantify the relationship between
chilling hours and budbreak, percent budbreak for
each seed source after 20 wk was plotted against
cumulative chilling hours. Examination of
residual plots after fitting linear
relationships, lack of fit tests, and tests for
nonconstant error variance (Weisberg 1985)
suggested that linear models were not appropriate
for the untransf ormed data. An arcsine square
root transformation of the budbreak proportions
was found to linearize the relationship and
stabilize the variance for seed sources 3000 and
4000 ft; a quadratic term was required for
fitting the regression equation for seed source
3500 ft.

METHODS

Two-year old seedlings from three seed
sources (courtesy of Warm Springs Indian
Reservation in central Oregon — seedlots 38-85112
[3000 ft], 38-85110 [3500 ft], and 38-85105
[4000 ft]) were selected for study. These seed
sources were chosen because seedlings could be
destined for sites which are plantable prior to
the average spring thaw in the nursery--a
situation in which fall lifting and overwinter
storage could be advantageous. Seedlings were
shovel-lifted on three dates (October 22,
November 5, and November 13, 1986) from four
replications of each seed source. An additional
lift of seedlings from seed source 3500 ft was
made on February 19, 1987. Immediately after
lifting, seedlings were packed in ice, trans-
ported to Corvallis, Greg., and placed in cold
dark storage (2°C) for approximately 12 h.
Seedlings from each replication then were potted
(10 seedlings per pot, 4 pots per seed source) in
a 1:1:1:2 soil : sand : peat : pumice mixture and
placed in a glasshouse with a 13-h extended
photoperiod supplemented with lighting from
300-watt incandescent bulbs. Daily maximum and
minimum temperatures were approximately 24^0 and
12''C, respectively. Soil moisture was maintained
near saturation.

Dormancy intensity was determined by scoring
each seedling for terminal budbreak (separation
of bud scales to reveal emerging needles) and
tallying percent budbreak for each pot of
10 seedlings. Seedlings were monitored for 20 wk
after each 1986 lift date; the 1987 lift was
assessed for 7 wk.

RESULTS

Chilling hours generally started to
accumulate during September, and increased later
in the fall, regardless of chilling temperature
range (fig. 1). However, as indicated in

0+- 1 1 , 1 1

SEP OCT NOV DEC JAN FEB

MONTH

Figure 1. — Cumulative chilling hours from

September 10, 1986 to February 19, 1987 at
20 cm above the surface for four temperature
ranges .

figure 1, cumulative chilling hours differed,
depending on the temperature range defined. For
example, cumulative chilling hours in February
differed nearly threefold between the temperature
range less than or equal to lO'C and that from
0 to S^C.

Sensors at the nursery weather station took
a temperature reading every 5 min and recorded
hourly averages. Cumulative chilling hours were
determined by summing the number of hours that
the average hourly temperature was within a given
range. Temperature ranges were defined as:
(1) less than or equal to 5''C (41''F) , (2) 0-5°C,

(3) less than or equal to 10°C (50°F), and

(4) 0-10°C. The starting date for accumulation
of chilling hours was set arbitrarily as
September 10. Chilling hours were calculated for
three sensor locations from September 10, 1986 to
February 19, 1987.

As expected, the later the lift date, the
more chilling hours the seedlings received
(table 1). Chilling hour data (temperature range
less than or equal to 5°C) for the sensor 20 cm
above ground surface indicated that the first
three lift dates differed by over 100 h each
(table 1) . More than 2400 chilling hours were
received by seedlings lifted February 19.

Percent budbreak was similar for all three
seed sources (fig. 2). Budbreak in the glass-
house environment was virtually nonexistent for
trees lifted October 22; no budbreak occurred

in seedlings from seed sources 3000 and 4000 ft.
Slightly more activity (8-13 percent budbreak
after 5 mo) occurred in seedlings lifted
November 5, and the percentage of seedlings which
flushed after 12, 16, and 20 wk increased
consistently for all seed sources lifted
November 13. Budbreak was especially accelerated
for seedlings (seed source 3500 ft) lifted
February 19 (fig. 3). These trees achieved the
same amount of budbreak after 6-7 wk as the trees
lifted on November 13 did after 20 wk.

In an attempt to determine a preferred
chilling range for releasing ponderosa pine
seedlings from dormancy, percent budbreak after
20 wk was plotted against cumulative chilling
hours for the four temperature ranges studied.
Similar to findings of Ritchie et al. (1985), all
chilling ranges exhibited similar patterns and
none was clearly advantageous. Therefore, the
range less than or equal to 5°C was utilized for
remaining analyses because of its practical use
in tallying chilling hours in some Northwest
nurseries (Ritchie et al. 1985).

The relationship between budbreak proportion
after 20 wk (transformed) and cumulative chilling
hours was linear for the 3000 and 4000 ft seed
sources. Regression equations derived from data
on these seed sources did not differ
statistically (p > .05); therefore, data were
combined to produce a single linear regression
model (fig. 4, budbreak = -1.074 + .003 [chilling
hours]). Differences in chilling hours accounted
for 74 percent of the variation in budbreak for

Table 1. Chilling hours accumulated from

September 10, 1986 to four 1986-1987 lifting
dates at three sensor locations for four
temperature ranges.

Sensor
location

Chilling hours
accumulated

Time period

Temperature ranges
above ground <5°C 0-5°C <10° 0-10°C

Sept

10-

-Oct

1.5 m

322

278

666

622

20 cm

396

290

644

538

surface

205

195

533

523

Sept

10-

-Nov

1.5 m

443

382

884

823

20 cm

533

391

856

714

surface

337

327

737

727

Sept

10-

-Nov

1.5 m

599

477

1065

943

20 cm

683

472

1029

818

surface

474

441

908

875

Sept

10-

-Feb

19l

1.5 m

2459

1466

3336

2343

20 cm

2478

1369

3238

2129

surface

2551

1863

3210

2522

LlI
Ql
GO
Q
Z)
CD

I-

LlI
O

UJ
CL

^Information from 4:00 p.m. December 8 to
11:00 a.m. December 9 not available.

8 12 16 20

WEEKS AFTER LIFTING

Figure 2. — Percent budbreak (+ SE) for seedlings
from seed sources (A) 3000 ft, (B) 3500 ft,
and (C) 4000 ft assessed for 20 wk after
three lifting dates.

these two seed sources (n = 24). A curvilinear
relationship existed for seed source 3500 ft
(n = 12), with a coefficient of determination
equal to .85 (fig. 4, budbreak = 2.874 -
.013 [chilling hours] + .00001 [chilling
hours] 2) .

DISCUSSION

The number of chilling hours required for
growth to resume following dormancy has been
estimated at 1200 h at 0-10°C or 1400 h below 5''C
for Douglas-fir (Ritchie and Dunlap 1980). Such
information for ponderosa pine is lacking. With
the assumption that differences in budbreak
between lifting dates were due to differences in
cumulative chilling hours, the results of this
trial suggest that seedlings from the tested
seedlots had a chilling requirement. Seedlings
in the greenhouse were never exposed to long
photoperiods (e.g., 16 h) , which can compensate
partially for inadequate chilling (Campbell and
Sugano 1975). Apparently, seedlings were in deep
dormancy during the early fall lift, and may have
been unable to resume growth because they needed
chilling hours (Perry 1971). Thus, seedlings
could have been released from dormancy with the
accumulation of chilling hours (e.g., Lavender
1985) .

In contrast to the findings of this trial,
Tinus et al. (1986) reported no chilling
requirement for ponderosa pine. They used a high
elevation (7000 ft) Arizona seed source and
raised seedlings in containers under greenhouse
conditions .

Chilling hour data were retrieved from the
weather station with only minor problems.
Installed recently (June 1986) for the USDA
Forest Service Reforestation Improvement Program
(see Rietveld, this proceedings), the weather
station immediately showed its potential use in
collecting beneficial information for the
nursery. Nonetheless, determination of chilling

WEEKS AFTER LIFTING
Figure 3. — Percent budbreak (+ SE) for seedlings
from seed source 3500 ft assessed for seven
weeks after lifting February 19, 1987.

Z 1.0

400 450 500 550 600 650

CHILLING HOURS

Figure 4. — Relationship between budbreak

proportion (transformed) and chilling hours
for seed sources (A) 3000 and 4000 ft, and
(B) 3500 ft.

requirements poses numerous problems. Not all
chilling temperature hours below a specified
quantity are equally effective in releasing
seedlings from dormancy (Ritchie et al. 1985).
In addition, the chilling period may be
interrupted by warm temperatures . The
relationship between chilling hours and release
of seedlings from dormancy under controlled
environments will be more intensively studied
during fall 1987. In addition, investigations of
the interaction between dormancy intensity of
fall-lifted trees and the ability to tolerate
long-term storage, as well as of effects of fall
lifting and long-term storage on seedling
carbohydrates and outplanting performance, are
planned for 1987.

ACKNOWLEDGEMENTS

The authors appreciate the support of the
Nursery Technology Cooperative, Oregon State
University, USDA Forest Service Bend Pine
Nursery, and the Warm Springs Indian
Reservation. We also thank Pete Owston, USDA
Forest Service, for the use of greenhouse space.

LITERATURE CITED

Campbell, R.K. , and A.I. Sugano. 1975. The
phenology of bud burst in Douglas-fir
related to provenance, photoperiod,
chilling, and flushing temperature.
Botanical Gazette 136 (3) : 290-298 .

Hermann, R.K. , D.P. Lavender, and J.B. Zaerr.

1972. Lifting and storing western conifer
seedlings. Research Paper 17, 8 p. Forest
Research Laboratory, Oregon State
University, Corvallis, Oreg.

Hinesley, L.E. 1982. Cold storage of Fraser fir
seedlings. Forest Science 28:772-776.

Hocking, D. , and R.D. Nyland. 1971. Cold

storage of coniferous seedlings. Applied
Forestry Research Institute Research Paper
No. 6, 70 p. State University College of
Forestry, Syracuse, New York, N.Y.

Hocking, D., and B. Ward. 1972. Late lifting
and freezing in plastic bags improve white
spruce survival after storage. Tree
Planters' Notes 23:24-26.

Lavender, D.P. 1985. Bud dormancy, p. 7-16.

In Evaluating seedling quality: principles,
procedures, and predictive abilities of
major tests: Proceedings of the workshop.
[October 16-18, 1984] Forest Research
Laboratory, Oregon State University,
Corvallis, Oreg.

Mullin, R.E., and W.R. Bunting. 1972.

Refrigerated overwinter storage of nursery
stock. Journal of Forestry 70:354-358.

Navratil, S. 1973. Pathological and physiologi-
cal deterioration of planting stock in cold
storage (literature review). 27 p. Forest
Research Branch, Ministry of Natural
Resources, Ottawa, Ontario.

Perry, T.O. 1971. Dormancy of trees in winter.
Science 171:29-36.

Ritchie, G.A. , and J.R. Dunlap. 1980. Root growth
potential: its development and expression in
forest tree seedlings. New Zealand Journal
of Forestry Science 10:218-248.

Ritchie, G.A. , J.R. Roden, and N. Kleyn. 1985.
Physiological quality of lodgepole pine and
interior spruce seedlings: effects of lift

date and duration of freezer storage. Cana-
dian Journal of Forest Research 15:636-645.

Stone, E.G., and G.H. Schubert. 1959. The

physiological condition of ponderosa pine
(Pinus ponderosa Laws.) planting stock as it
affects survival after cold storage.
Journal of Forestry 57:837-841.

Tinus, R.W. , K.E. Burr, S.J. Wallner, and R.M.
King. 1986. Relation between cold
hardiness, root growth capacity, and bud
dormancy in three western conifers,
p. 80-85. In Proceedings: combined Western
Forest Nursery Council and Intermountain
Nursery Association meeting. [Tumwater,
Wash., August 12-15, 1986] USDA Forest
Service Technical Report RM-137, 164 p.
Rocky Mountain Forest and Range Experiment
Station, Fort Collins, Colo.

Tung, C.H., L. Wisniewski, and D.R. DeYoe.

1986. Effects of prolonged cold storage on
phenology and performance of Douglas-fir and
noble fir 2+0 seedlings from high-elevation
sources . Canadian Journal of Forest
Research 16:471-475.

van den Driessche, R. 1977. Survival of coastal
and interior Douglas fir seedlings after
storage at different temperatures, and
effectiveness of cold storage in satisfying
chilling requirements. Canadian Journal of
Forest Research 7:125-131.

Weisberg, S. 1985. Applied linear regression.
Second edition. 324 p. John Wiley and
Sons, New York, N.Y.

A Status Report on Nursery and Reforestation Projects
at the Missoula Technology and Development Center^

Ben J. Lowman^

Abstract. — This paper presents an overview of work
underway in the nursery and reforestation program at the
Missoula Technology and Development Center. Projects
include the Seedling Counter, Seeders, Seedling Handling
Equipment, Root Regeneration Chambers, a Stake Driver, an
Improved Planting Auger, and Field Storage.

INTRODUCTION

The Missoula Technology and Development
Center (MTDC) has a long history of development
in nursery and reforestation work. Current
projects at MTDC are indicative of a continued
commitment to improve Forest Service reforesta-
tion and nursery programs. The status of
current projects follows:

Nursery Technical Services. — Our goal in
this project is to provide engineering assist-
ance to Forest Service nurseries and to
disseminate information to help nursery managers
keep current with technological advances.
Under this project, we maintain drawing files on
nursery equipment and send them to nursery
managers and others on request. In FY 1987 MTDC
built 14 Root Growth Chambers and drawings were
prepared based on Dr. Tinus and Dr. Reinfelt's
design. In addition, electrical protection was
provided for 44 weather stations associated
with the Reforestation Improvement Program.
Detailed construction plans for two sizes and
types of Root Growth Chambers are available on
request. '

Seedling Counter. — Forest Service nursery
managers must have an accurate and current count
of their seedling crop by age and seedlot for
inventory, planning, and scheduling. Our goal
is to provide a fast, accurate, and inexpensive
system for counting seedlings in the nurserybed.
After analyzing current technology. Center
engineers decided that an optical-electrical
approach was the most feasible. A contract was
awarded to Dr. Glenn Kranzler at Oklahoma State
University to continue his work on seedling
counting. Dr. Kranzler performed laboratory
tests that provided information Center engineers
used to design a prototype counting system. The
counting system uses laser beams with linear array
detectors and light emmitting diodes with linear
array detectors. Preliminary tests at Lucky
Peak Nursery in Boise, Idaho, showed promise.
Further tests and refinements of the counter will
continue in 1988.

Seeders . — Uniformly spaced seed in the
nurserybed helps determine the quality of stock
produced. Nursery managers need a precision
seeder to accomplish this. MTDC continues to
monitor industry to determine the state-of-the-
art in precision seeders. We are particularly
interested in high speed transplanting equipment
used in row crops. In 1988, Center engineers
will conduct lab tests on at least two precision
seeders to determine their applicability for
sowing longleaf pine seed. MTDC engineers will
also design, fabricate, and test an improved
hand seeder for sowing small progeny seed lots.

Seedling Handling Equipment
result of a survey of Federal nur
MTDC designed, fabricated, and te
box pickup and conveyor system fo
full of trees from the ground to
transporting to the packing shed,
cation, and initial testing will
the end of 1987. Information and
this system will be available in
1988.

— As the direct
sery managers,
sted a prototype
r moving tubs
a trailer for

Design, fabri-
be completed by

drawings of
the spring of

Stake Driver — A three-point hitch-mounted
stake driver was designed, built, and transported
to Bend Pine Nursery for use in installing netting
that protects seeds from birds. This stake driver
was used in the spring of 1987 with excellent
success. Drawings are available.

Improved Planting Auger. — The Intermountain
Forest and Range Experiment Station experimented
with varying the shape of planting holes to improve
seedling establishment and growth. They found
that cone-shaped holes appear best suited for
bareroot seedlings. MTDC was asked to design and
build several styles of cone-shaped augers for
evaluation. Six prototype augers were built and
evaluated in the Intermountain and Pacific North-
west Regions. Personnel selected a prototype
design that creates a 4-inch diameter hole. Its
bottom 6 inches is tapered to about 1 inch. Ten
of these augers are being field tested. MTDC will
refine the augers in 1988.

Field Storage. — The nursery manager must,
protect seedlings from injury and damage from
the time they emerge until they reach their
shipping destination. Nursery managers usually
have the equipment, materials, and trained
personnel to provide the necessary protection,
but field units that take possession of the
planting stock often cannot provide protection.
Portable pick-up sized cold transport units are

needed. In FY 1987, center personnel contacted
field units to define the requirements for such
transport and storage units. One manufacturer
sent a proposal for a unit using the truck 12-
volt system, batteries, solar panels, and eutectic
cold plates for refrigeration. The proposal has
been sent to 15 field units for their comments.
MTDC will analyze these comments and base further
work on the results of this analysis.

Grading Pine Seediings with Machine Vision^

Glenn A. Kranzler and Michael P. Rigney^

A machine vision technique for grading pine seedhngs at
production Une rates was developed. Singulated seedhngs were
inspected on a moving belt. Classification as acceptable or cull was
based on minimum criteria for stem diameter, shoot height, and
projected root area. Individual seedlings were graded in approximately
0.25 seconds. Average classification error rate was 5.7 percent.

INTRODUCTION

Hundreds of millions of tree seedlings are grown
each year in commercial, federal, and state nurseries. At
harvest, these bare-root seedlings are graded to remove
inferior stock and improve productive potential.

Grading is typically performed manually by
grasping individual seedlings from a conveyor belt and
applying a number of visual quality criteria. Manual
inspection tends to be labor-intensive and costly.
Seedling classification is subjective and susceptible to
human error. Grading into more than two classes is not
feasible. Valuable production data such as seedling
count and classification statistics are difficult to obtain.
Disadvantages of manual grading have spurred growing
interest in automated alternatives.

A seedling grading machine was commercially
tested by Lawyer (1981). This mechanical system
measured stem diameter, shoot height, count, and
classified seedlings into three grades. However,
productivity was only 1000 seedlings per hour, a rate
approximately three times slower than manual grading.

A digital electronic system for measuring and
recording seedling diameter, height, root area index
(silhouette area), and sample number was described by
Buckley et al. (1978). Potentiometric transducers and a
linear 1024 element photodetector were employed.
Although measurements were accurate, the apparatus
was much too slow to grade large quantities of seedlings
at production line rates.

Digital image processing has been successfully
implemented in many industrial and agricultural
inspection processes. It has demonstrated high accuracy
and throughput and has permitted 100% inspection in
applications which were previously not feasible

^ Paper presented at the Intermountain Forest
Nursery Association Meeting. [Oklahoma City, OK,
Augusj 10-14, 1987]

Respectively, Professor of Agricultural
Engineering, Oklahoma State University, Stillwater, OK,
and Apphcations Engineer, International
Robomation/Intelligence, Carlsbad, CA.

(Kranzler 1985). Machine vision inspection would
appear to be an ideal tool for addressing the tree
seedHng grading problem.

OBJECTIVES

This study was initiated to investigate the ability of
machine vision to grade bare-root pine seedlings under
nursery production conditions. Specific objectives
included:

1. Develop and implement a machine vision
algorithm for obtaining grade classification
measurements at production line rates,

2. Evaluate performance in terms of measurement
speed, precision, and accuracy of classification.

METHODS AND MATERIALS

Assumptions

Several assumptions were adopted concerning the
environment in which the grading would be performed.
First, seedlings would be singulated, permitting only one
seedling to appear within the camera field-of-view at a
given time. Second, shoot orientation and lateral
position would be loosely constrained. Finally, it was
assumed that a black conveyor belt would be used to
transport seedlings beneath the cameras.

Equipment

Equipment included a conveyor belt, machine
vision computer, cameras, lenses, and lights. To simulate
production grading operations, a variable-speed belt
conveyor was constructed to transport seedlings for
inspection. The black belt shiny surface was dulled by
sanding to minimize specular reflection.

An International Robomation/Intelligence (IRI)
D256 machine vision development system was used.
Images were digitized into an array of 256 X 240 picture
elements (pbcels) with 256 grey levels. A high-speed
hardware coprocessor performed computationally
intensive operations such as image filtering and edge

100

detection, runlength-encoding, and moments
calculations. Software was developed in the C
programming language.

Two Hitachi KP-120U solid-state black-and-white
television cameras were employed for image acquisition.
Camera 1 was used to obtain a close-up image of the
seedling root collar zone. A field-of-view (FOV)
approximately 12.8 cm (5 in) square provided a 0.5 mm
(0.20 in) pixel resolution (fig.l). Camera 2, with a FOV
approximately 51 cm (20 in) square and resolution of 2.2
mm, acquired an image of the entire seedling.

Illumination was provided by fluorescent room
lighting and strobed xenon flash. Relatively low-level
room lighting was adequate for detection of the moving
seedlings in the FOV of camera 2. When a seedling was
detected, synchronized strobe lamps were triggered to
obtain a "frozen" image with each camera.

Grading Scheme

Morphological characteristics are used in the
grading of most nursery stock. These characteristics
mclude stem diameter at the root collar, shoot height and
weight, root weight or volume, root fibrosity, foliage
color, presence of terminal buds, root/shoot volume
ratio, and ratio of top height to stem diameter (sturdiness
ratio) (Forward 1982, May et al. 1982). Stem diameter,
shoot height, and root volume are generally given priority
and were adopted as the grading criteria for this study.
Of these three, stem diameter is typically considered
most important.

To meet image processing time constraints, we
decided to emphasize stem diameter measurement
accuracy and obtain close approximations of shoot height
and of root volume as indicated by projected root area
(root area index). A classification scheme based on
minimum acceptable values of these three parameters
(May et al. 1982) is given in table 1. Seedlings were
graded into two classes; acceptable and cull.

Figure 1. Field-of-view for cameras 1 and 2. Note
Waitfor window.

ALGORITHM

The grading algorithm is composed of several
separate tasks. These operations are: calibration,
seedling detection, measurement of orientation, location
of the root collar, diameter measurement, root area
measurement, shoot height measurement, grade
classification, and recording of seedling statistics. A
detailed description of the algorithm is presented by
Rigney (1986).

Accuracy of diameter measurement and the
probability of the root collar appearing within the
camera view influenced the choice of FOV for camera 1.
Because the position of the root collar cannot be closely
constrained, a relatively wide FOV is necessary. We
decided to make the FOV as large as possible, while
maintaining a measurement precision of at least 0.5 mm
(0.20 in).

Seedling Detection

A program loop is entered in which successive
images are acquired with camera 2 (wide FOV). Each
image is multiplied by a template which defines a
window in which seedling detection will trigger
subsequent operations (Waitfor window, fig. 1). After
grey-level thresholding, the area occupied inside the
vidndow is calculated. When the area exceeds a
programmed number of pixels, the presence cf a seedling
is assumed, and an image is automatically acquired from
each camera with strobe illumination.

Seedling Orientation

The image from camera 2 is next processed to
determine shoot orientation on the conveyor belt.
Coprocessor moments calculations provide the angle
between the seedling major axis and a line perpendicular
to the direction of travel. This angle is used as a
correction factor in subsequent calculations of stem
diameter and shoot height. Because measurement error
becomes excessive at large angles, seedlings are not
graded if the orientation angle is greater than thirty
degrees.

Location of the Root Collar

Accurate location of the root collar is crucial for
subsequent measurement of stem diameter, shoot height,
and root area index. The image from camera 1 is
thresholded, yielding a binary image showing the stem,
roots, branches, and needles (fig. 2). This image is then
runlength-encoded and processed line-by-line. The
runlength code is an array of column numbers of the
transitions from black-to-white and white-to-black on
each line of a binary image.

If the number of transitions on a line is less than or
equal to a selected variable (initially two), that line is a
candidate for the root collar location. Additionally, from
a priori knowledge about stem diameters, the maximum
distance between paired transitions must be between 5
and 18 pixels (2.5 to 9 mm) for a line to be a root collar
candidate. The root collar is located at the average of

101

Table 1. -Grading scheme for loblolly pine seedlings

Stem Diameter Root Area Index Shoot Height Grade

(mm) (pixels) (cm)

3.0 - 8.0 > 200 > 16 Acceptable

< 3.0 or > 8.0 any any Cull

3.0 - 8.0 < 200 or < 16 Cull

the largest set of adjacent candidate lines, if that set
contains at least six members. If the collar is noi found
using the initial value for number of transitions, the
procedure is repeated for values of four and then six.
When the root collar (line number) is found (fig. 3), it is
stored along with the collar midpoint (column number)
and number of adjacent candidate lines about the collar
line.

If the root collar is still not located, the procedure
is repeated after thresholding at a higher grey level. At
this increased threshold, only the stem, major branches,
and roots are visible (fig. 3). The use of two grey-level
thresholds for collar location improves overall algorithm
performance. A low threshold limits the number of
candidate root collar lines for typical seedlings, reducing
image processing time. A high threshold may be
required to minimize the effect of needles, branches, and
roots which are sometimes present in the root collar zone
(figs. 2 & 3).

Measurement of Stem Diameter

Diameter measurement is performed inside a
hardware window implemented about the root collar in
the image from camera 1. Window size is defined by the
set of candidate coUar lines found in the collar location

subroutine. The windowed zone is processed with an
edge detector favoring vertical edges and thresholded,
resulting in a binary image of the strongest stem edges
(fig- 4).

The image is then runlength-encoded. For lines
which contain four or more transitions (two transitions
occur at each stem edge), the two consecutive odd
transitions which bracket the collar midpoint are found.
If these transitions are within ten pixels (5 mm,
horizontally) of the collar midpoint, the distance between
the transitions is assumed to be the stem diameter on
that line. When the processing of candidate lines is
complete, and at least one line has provided a distance
measure, the stem diameter is calculated as the average
of the diameters on candidate lines.

Measurement of Root Area Index

The image from camera 2 is initially windowed
from the root collar to the bottom of the image and
processed with a specialized edge detector. The image is
then thresholded, yielding a binary image with a
maximum number of root pixels and minimum
background noise (fig. 5). The number of pucels inside
the hardware window is defined as the root area index.

Figure 2. Camera 1 close-up image details root collar

region. Figure 3. Algorithm locates root collar.

102

Measurement of Shoot Height

The image from camera 2 is thresholded and
runlength-encoded. Starting at the top of the image,
each line is checiced to determine if the maximum
distance between paired transitions exceeds five pixels.
The seedling top is assumed to be located when four
consecutive lines meet this criterion. Shoot height is
defined as the distance between the seedling top and root
collar.

Main Program

Inside the main program loop, values returned by
subroutines are tested to control program flow. If all
grading subroutines are successful in their respective
tasks, a series of if-else statements is used to assign a
grade to the seedUng. Whenever a subroutine fails its
task, the seedling is recorded as not gradable. Finally,
measured seedling parameters, grade, and count, are
written to a statistics file.

Calibration

Proper calibration of threshold values and scale
factors is essential for optimum algorithm performance.
The calibration subroutine initializes sixteen parameters
with default values. The user is then provided an
opportunity to alter the default values interactively. A
wooden dowel of known diameter and length is used to
calibrate scale factors. Grey level thresholds are set
using a representative seedling.

EVALUATION

A reference set of 100 loblolly pine (Pinus tacda
L.) seedlings was manually measured and graded. Stem
di? meters ranged from 2.3 to 6.0 mm. Performance of
th machine vision system was then evaluated by grading
each of the seedlings twenty times. Shoot orientation
was limited to plus-or-minus thirty degrees from vertical.

Figure 4. Image is processed to define stem edges in
root collar zone.

Figure 5. Image is processed to highlight seedling
roots.

and root collar location was constrained to the FOV of
camera 1.

Time required for the algorithm to grade a seedling
averaged approximately 0.25 seconds. Strobe
illumination provided reliable image capture at conveyor
speeds of up to 1.0 m/s (3.28 ft/s), corresponding to a
grading rate exceeding three seedlings per second. To
facilitate manual placement of the seedlings on the
grading belt, tests were conducted at a velocity of 0.46
m/s (1.5 ft/s).

The classification error rate averaged 5.7 percent
for the set of 100 seedlings (table 2). This is very
acceptable performance, bettering manual grading
operations which have an average misclassification rate
or seven to ten percent (Boeckman, 1986). As expected,
a large part of the classification error was attributable to
seedlings which straddled the borderline between
acceptable and cull with respect to diameter and root
area. Such seedlings comprised 17 percent of the grading
test set and had an average misclassification rate of 23.2
percent. The remaining 83 seedlings had an average
misclassification rate of 2.2 percent (table 2). Since there
is no significant penalty for misclassification of
borderline seedhngs, 2.2 percent misclassification may be
a better indicator of algorithm performance.

Measurement precision was excellent, considering
the spatial resolutions of cameras 1 and 2, which were 0.5
mm/pixel and 2.2 mm/pixel respectively. The coefficient
of variation of 20 measurement repetitions averaged 7.6,
12.2, and 4.1 percent for stem diameter, root area, and
shoot height, respectively.

The few seedlings which showed the largest
deviations in measured parameters were characterized
either by needles extending down past the root collar, or
by roots bent upward past the root collar, or both. The
subroutine which located the root collar performed
inconsistently on such seedlings. A few such seedlings
could not be graded.

103

Table 2.~Percent misclassification of 100 seedlings, 20 reps

Manual Acceptable Cull Total
Grade

# mis. # mis. # mis. n.g.

Borderline 6 31.7% 11 18.6% 17 23.2% 2.6%

Easily Classified 63 2.2% 20 2.0% 83 2.2% 2.3%

All 69 4.7% 31 7.9% 100 5.7% 2.3

n.g. = not gradable mis. = misclassified

We anticipate that algorithm performance could be
enhanced with minor modifications. First, the shoot area
could easily be measured, allowing calculation of a
root/shoot ratio. Calculation of the sturdiness ratio
(diameter /height) would also be straightforward.
Collection of a data base with the machine vision system
would allow implementation of a statistical classification
scheme, leading to improved grading performance.

The measurement precision demonstrated by the
algorithm suggests use for classification of seedlings into
several acceptable grades. Additional grade definitions
could be optimized for specific planting sites. Finally, we
expect that the comprehensive statistics collected in a
commercial implementation would make machine vision
grading a valuable nursery management and research
tool.

SUMMARY AND CONCLUSIONS

This study has demonstrated that machine vision
can provide accurate production rate grading of
harvested pine seedlings. Singulated seedlings were
transported on a conveyor belt, with shoot orientation
and root collar position loosely constrained. Seedlings
were classified as acceptable or cull on the basis of stem
diameter, shoot height, and projected root area.

Tests with loblolly pine seedlings revealed excellent
system performance. Seedlings were graded in
approximately 0.25 seconds, with an average
classification error rate of 5.7 percent. These results
exceed manual grading performance, which typically
requires one second per seedling with an error rate of
seven to ten percent. Misclassification was largely due to
seedlings with borderline diameter and/or root area, and
the occurrence of branches or roots in the root collar
zone. Measurement precision was adequate for seedling
classification into several grades, suitable for specific
planting sites.

DISCLAIMER

Reference to commercial products or trade names
is made with the understanding that no discrimination is
intended or endorsement imphed.

REFERENCES CITED

Boeckman, W. 1986. Personal contact. Weyerhaeuser
Nursery, Fort Towson, OK.

Buckley, D. J., W. S. Reid and K. A. Armson. 1978. A
digital recording system for measuring root area
and dimensions of tree seedlings. Transactions of
theASAE. 21(2):222-226.

Forward, P. W. 1982. Stock production specifications -
bare root stock. Artificial Regeneration of
Conifers in the Upper Great Lakes Region.
Michigan Technological University, Houghton, MI.
pp. 260-268.

Kranzler, G. A. 1985. Applying digital image processing
in agriculture. Agricultural Engineering. 66(3): 11-
13.

Lawyer, J. N. 1981. Mechanization of nursery

production of bare root deciduous planting stock.
Forest Regeneration. ASAE Publication 10-81, pp.
30-37. ASAE. St. Joseph, MI.

May, J. T., E. W. Belcher, Jr., C. E. Cordell, T. H. Filer,
Jr., and D. South. 1982. Southern Pine Nursery
Handbook. Forest Service, USD A.

Rigney, M. P. 1986. Machine vision for the grading of
pine seedlings. Unpublished MS Thesis.
Agricultural Engineering Department, Oklahoma
State University, Stillwater, OK.

104

Mycorrhizae Nursery Management for Improved Seedling
Quality and Field Performance^

2 3 A

Charles E. Cordell, Jeffrey H. Owen, and Donald H. Marx

Abstract . --Nursery and field outplanting studies have
repeatedly demonstrated that selected ecto- and endomycorr-
hizae on nursery seedlings reduce culls and improve field
survival eind growth. Mycorrhizae are significantly affected
by nursery soil factors such as pH, drainage and moisture,
fertility, and organic matter, and by cultural practices
such as soil fumigation, cover crops, and pesticide applica-
tions. Seedling lifting, storage, and planting practices
should be designed to retain the maximum number of feeder
roots and associated mycorrhizae as possible. Inoculum of
several species of ectomycorrhizae is commercially avail-
able, along with the necessary technology and machinery to
be incorporated into standard bare-root and container nur-
sery operations. Nurserymen and foresters are challenged
to utilize mycorrhizae technology as an integral component
of seedling production and forest regeneration.

INTRODUCTION

Seedling quality and field performance are
largely governed by processes occurring xjnder the
soil surface in the root zone of seedlings. Ab-
sorption of water and nutrients is a function of
the amount and quality of growing root tips or
feeder roots. The feeder roots of most tree
species are infected by specialized fungi that
form beneficial associations called mycorrhizae
(fungus-roots) . These symbiotic structures
greatly increase root absorption efficiency and
are vital to the survival and growth of both the
host tree and the fungus. Compared to nonmycor-
rhizal roots, those infected by mycorrhizal fungi
have increased absorptive capacity, nutrient fix-
ation, resistance to soil pathogens, and longev-
ity. As the main interface between seedling and

Paper presented at the Intermountain
Forest Nursery Association Meeting, Oklahoma
City, ^kla. August 10-14, I987.

Charles E. Cordell is National
Mycorrhizae Applications Coordinator, USDA Forest
Service, Forest Pest Management, Region 8,
Asheville, N.C.

Jeffrey H. Owen is Plant Pathologist,
USDA Forest Service, Forest Pest Management,
Region^^B, Asheville, N.C.

Donald H. Marx is Director, Institute
for Mycorrhizal Research and Development. USDA
Forest Service, Southeastern Forest Experiment
Station, Athens, Ga.

Figure 1. --Hardwood seedling feeder root infected
with the endomycorrhizal fungpjs , Glomus sp.
(left) and a mass of Pisolithus tinctorius
(Pt) ectomycorrhizae on a southern pine
seedling root (right) .

soil, mycorrhizae are a key measure of root sys-
tem quality and are a vital component of inte-
grated nursery management.

Mycorrhizae are of two biological types:
endomycorrhizae , which actually penetrate host
cells; and ectomycorrhizae, which grow between
the root cells and cover the root surface with a
mantle of fungus h5T3hae (Fig. 1). Most hardwood

105

tree species, including maple, sweetgum, syca-
more, ash, walnut, and poplar, along with some
conifers, including cypress, redwood, and arbor-
vitae, form endomycorrhizae and depend on them
for normal growth. This mycorrhizal type occurs
on all agronomic crops, including nursery cover
crops such as sorghum, corn, and the grasses.
Ectomycorrhizal fungi are associated with tree
species which include pine, spruce, fir, alder,
beech, oak, and hickory. Both ecto- and endomy-
corrhizal fungi have very broad host ranges.

Endomycorrhizal fungi penetrate cortical
cells of infected roots and form nutrient-
exchanging structures (arbuscles) inside them. A
loose network of fungal hyphae grows from the
feeder root surface, extending the effective area
of the root system. Endomycorrhizal roots absorb
and utilize nutrients, particularly phosphorous,
better than nonmycorrhizal roots. Thick-walled
spores (vesicles) may develop in feeder root
tissue, on the root surface, or in the root zone.
These microscopic "vesicular-arbuscular" (VA)
mycorrhizal fungi do not modify root morphology
or produce conspicuous above-ground fruiting
bodies, as do the ectomycorrhizal fungi.

Ectomycorrhizal feeder roots are visibly
different from nonsymbiotic roots. They usually
appear swollen, forked, more prolific, and diff-
erently colored. Fungal hyphae cover the feeder
root in a dense mantle. Strands of fungal hyphae
radiate into the soil and to the bases of fruit-
ing bodies produced by these fungi. Ectomycor-
rhizal fungi depend on their hosts for simple
carbohydrates, amino acids, and vitamins to com-
plete their life cycles and produce their spore-
disseminating fruiting bodies. They benefit
their hosts by increasing water absorption and
accumulation of nitrogen, phosphorous, potassium,
calcium, and other nutrients (Marx 1977) •

Extensive mycorrhizae research conducted by
the USDA Forest Service and a number of cooper-
ating forestry agencies has identified the pri-
mary functions of mycorrhizae in tree seedling
physiology and the nursery management factors
that limit mycorrhizal establishment. Technology
has been developed recently for the artificial
inoculation of bare-root and container nurseries
with selected ectomycorrhizal fungi. Several
types of commercial inoculum are currently avail-
able for selected ectomycorrhizal fungi and can
be operationally utilized in forest tree nur-
series. Techniques have been developed to iden-
tify and quantify ectomycorrhizae occurring on
seedling root systems utilizing ectomycorrhizae
as a measure of seedling quality. In numerous
container and bare-root nursery studies, along
with forest and reclaimed mineland outplanting
studies, selected ectomycorrhizae have signifi-
cantly increased seedling quality and field
performance. Provided with this unique technol-
ogy, nurserymen, foresters, and mineland reclama-
tion specialists are challenged to understand and
utilize mycorrhizae as an integral component of
nursery seedling production and forest
regeneration .

BENEFITS

Ectomycorrhizae

Most conifer tree species, including all
pines, cannot grow without ectomycorrhizae. This
obligate dependency of trees on their fungal sym-
bionts has been thoroughly substantiated through
extensive laboratory and field research, and
through unsuccessful attempts to introduce tree
species into areas where their symbiotic fungi
were not present. After the ectomycorrhizal
fungi were introduced, trees were successfully
established (Marx I98O) . In forest tree nur-
series in the United States, there is seldom a
total absence of ectomycorrhizal fungi. Seed-
lings form ectomycorrhizal associations with
naturally occurring fungi that originate from
windblown spores produced by fruiting bodies in
adjacent windbreaks, seedling beds, or forest
stands. In nurseries where cultural practices or
new field conditions have reduced ectomycorrhizal
fungus populations, seedlings grow poorly and do
not respond to increased fertilization. Pockets
of seedlings that do have ectomycorrhizae or even
had ectomycorrhizae established earlier in the
season, have increased stem caliper and height,
improved foliage color, and a more balanced
shoot: root ratio than adjacent stunted seedlings
which are deficient in ectomycorrhizae.

The ectomycorrhizal fungi that occur most
commonly in bare-root nurseries, such as
Thelephora terrestris (Tt) , are ecologically
adapted to the favorable growing conditions in
nursery soils. However, these fungi are poorly
adapted to the adverse conditions of many refor-
estation and reclamation sites. Research by the
USDA Forest Service has focused on one particular
ectomycorrhizal fungus, Pisolithus tinctorius
(Pt) , which is especially tolerant of extreme
soil conditions, including low pH, high tempera-
ture, drought, and toxicity. The conditions,
which occur on many forest sites, inhibit other
naturally occurring ectomycorrhizal fungi and
their host trees (Marx, Cordell, and others
X98k) . Pt was selected because of its adapta-
bility, ease of manipulation, wide geographic and
host range, and demonstrated benefits to trees,
both in the nursery and on reforestation and
reclamation sites.

Many conifer and some hardwood species on a
variety of nursery sites have been artificially
inoculated with Pt by treating seedling con-
tainers and prefumigated nursery seedbeds (Fig.
2). Effective Pt vegetative inoculum has con-
sistently improved the quality of nursery seed-
lings. National container and bare-root nursery
evaluations have demonstrated the effectiveness
of several formulations of Pt inoculum on
selected conifer seedling species (Marx, Ruehle,
and others I98I; Marx, Cordell, and others 1984).
During the past 10 years, over 125 bare-root nur-
sery tests have been conducted in 38 states. A
companion evaluation of container seedlings also
demonstrated the effectiveness of commercial Pt
vegetative inoculum in I8 nurseries in 9 states

106

and Canada. Inoculated seedlings have signifi-
cantly outperformed uninoculated checks (Fig. 3)
that contained only naturally occurring ectomy-
corrhizae (predominantly Tt) . Results obtained
from 34 nursery tests conducted during 3 years
showed that Pt inoculation of southern pine seed-
lings increased fresh weight by I7 percent,
increased ectomycorrhizal development by 21 per-
cent, and decreased the number of cull seedlings
at lifting time by 2? percent (Fig. ^i) . The
nursery failures that have occurred have been
correlated with such factors as ineffective Pt
inoculum, excessively high soil pH (above 6.5),
improper nursery cultural practices, pesticide
toxicity, or severe climate (Cordell I985).

Inoculated seedlings have been planted on
routine forestation sites, strip-mined areas,
kaolin wastes, and Christmas tree farms scattered
over the United States. Currently, over 100 Pt
ectomycorrhizal outplantings involving 12 species

Figure 2. — Abundant Pt fruiting body production
between 2-0 eastern white pine seedbeds pre-
fumigated and inoculated with commercial Pt
vegetative inoculum.

Figure 3- — 1-0 loblolly pine seedlings with Pt
ectomycorrhizae (left) and with only natu-
rally occurring ectomycorrhizae (right) .

PERCENT INCREASE/DECREASE

20 -

10 ■

-10 •

-20 -

-30 L

FRESH WEIGHT MYC0RRHI2AE CUOS

Figure 4 . --Increases in seedling fresh weights
and ectomycorrhizal development and
decreases in the number of culls are
obtained by inoculating seedlings with Pt.

of conifers are being monitored in 20 states.
Over 75 of these outplantings contain southern
pine species (primarily loblolly [Pinus taeda L.]
and slash pine [P. elliottii Engelm. var.
elliottii] ) in the Southern United States. Most
of these outplantings have been established since
1979; consequently, benefits to mature forest
stands cannot be estimated. At widespread loca-
tions, however, tree survival and early growth of
several conifer species have been significantly
improved by Pt inoculations in the nursery. A
significant increase (25+%) in tree volume is
still being observed on Pt-inoculated eastern
white (P. strobus L.), loblolly, and Virginia (P.
virginiana Mill.) pines over check trees after 10
years in western North Carolina. Loblolly pine
volume was 31 percent higher, and white pine vol-
ume was 151 percent higher than in uninoculated
checks. Outplantings established by the Ohio
Division of Mineland Reclamation on mineland
reclamation sites in southern Ohio during 1982
and 1983 showed an average survival increase of
23 percent and 24 percent, respectively, for
Virginia and eastern white pine seedlings over
routine nursery seedlings after 2 years in the
field. Treating longleaf pine (Pinus palustris
Mill.) seedlings with Pt inoculum in the nursery
increased their survival over uninoculated checks
by 17 percent after 3 years in the field in four
Southern States. Inoculation of longleaf pine
with Pt, in combination with selected cultural
practices in the nursery and a benomyl root
treatment prior to field planting, has signifi-
cantly increased the field survival and early
growth of bare-root seedlings (Kais, Snow, and
Marx 1981 ; Hatchell I985) .

After 8 years on a good-quality, routine
forestation site in southern Georgia, a 50 per-
cent increase was observed in volume/acre growth
of Pt-inoculated loblolly pine over controls.
The improvement was correlated with continued
Pt-inoculated tree growth during seasonal periods

107

of severe water deficit. Similar relationships
have been found in other field studies. Root
systems with abundant Pt ectomycorrhizae are
apparently more capable of extracting water and
essential nutrients from soil during periods of
extreme water stress than are root systems with
fewer ectomycorrhizae or with other species of
ectomycorrhizal fungi. These reported benefits
do not even show the full potential of Pt,
because as the fungus thrived on inoculated
treatment plots and spread to uninoculated plots,
treatment integrity was lost after 3 years.

Endomycorrhizae

Any nurseryman who has encountered stunted,
chlorotic hardwood seedlings in a prefumigated
bed, despite proper fertilization, irrigation,
and disease control, is fully aware of the bene-
fits provided by endomycorrhizal fungi. Nursery
studies have repeatedly shown increases in the
quality of seedlings with endomycorrhizae, com-
pared to those without endomycorrhizae (Fig. 5) •
Root and stem weight of black cherry, boxelder,
green ash, red maple, sweetgum, sycamore, and
black walnut seedlings were significantly in-
creased following treatment with VA mycorrhizal
fungi (Kormanik, Schultz, and Bryan I982) . Black
walnut seedlings grown in nursery soils infested
with VA fungi retained their leaves longer,
extending the effective growing season by 6 to 8
weeks and resulting in greater root and shoot
biomass production (Kormanik I985) . Benefits
from endomycorrhizae were greatest at phosphorous
levels below 75 PPm (150 lb/acre). At higher
soil phosphorous concentrations, nonmycorrhizal
seedlings grew as well as endomycorrhizal seed-
lings (Kormanik et al. 1982; Kormanik 1985). In
field studies where available phosphorous was low
(10-15 Ppm) , hardwood seedlings that had abundant
lateral roots and endomycorrhizae did not die

(mm

1171

• CTunotTin
r mm

Figure 6. --Observed correlation between increased
number of sweetgum seedling primary lateral
roots (= or > 1 mm diameter) and improved
seedling quality.

back as much after outplanting as those with few
lateral roots and poor endomycorrhizal develop-
ment. In most forest soils, long-term benefits
from endomycorrhizal treatments in the nursery
are difficult to determine because nonmycorrhizal
root systems are quickly colonized by naturally
occurring VA fungi (Kormanik I985) .

In the extended process of evaluating root
system development in relation to VA fungi, a
high correlation was found between the number of
primary lateral roots (1 mm or more in diameter)
and seedling performance after outplanting. In a
1-year-old sweetgum plantation, height, root-
collar diameter, and survival increased and top
dieback decreased (Fig. 6) as the number of lat-
eral roots increased (Kormanik 1986) . The previ-
ously observed correlation between the number of
lateral roots and seedling quality remained con-
sistent as additional tree species were examined.
Findings may be applicable to conifers as well as
hardwoods and ecto- as well as endomycorrhizal
host trees. While the effects of lateral root
morphology appear to be independent of mycor-
rhizal condition, they demonstrate the importance
of assessing root systems as a component of
seedling quality.

Figure 5- — Inoculation with a VA endomycorrhizal
fungus increased seedling biomass of eight
hardwood species (left) compared to noninoc-
ulated seedlings (right).

^Marx, D.H., C.E. Cordell, and A. Clark.
1987. Eight-year performance of loblolly pine
with Pisolithus ectomycorrhizae on a good quality
forest site. Manuscript in press. USDA Forest
Service, Southeastern Forest Experiment Station,
Institute for Mycorrhizal Research and Develop-
ment, Athens, Ga. [Submitted to Southern Journal
of Applieid Forestry.]

Identification and Quantification

A nurseryman who hopes to maximize seedling
quality should learn to recognize and perhaps
quantify the dominant mycorrhizal types occurring
on seedlings. Ectomycorrhizal fungi are most
easily identified by their fruiting bodies--the
numerous puffballs or mushrooms that develop some
time after seedlings have been colonized. The
fungi can also be recognized on the basis of dis-
tinct morphology of ectomycorrhizal feeder roots.
Although over 2,000 ectomycorrhizal fungi are
known, only a few (1 to 3) species usually are
found in a nursery. On western fir, spruce, and
pine seedlings, gilled mushrooms of Laccaria

108

(Fig. 7a) and Hebeloma (Fig. 7b) species, pored
mushrooms of Suillus species (Fig. 7c) , and puff-
balls of Rhizopogon species (Fig. 7d) are common.
On or near pine seedlings in the South, puff balls
of Pisolithus tinctorius (Fig. Je) and the papery
thin, funnel-shaped mushrooms of Thelephora
terrestris (Fig. 7f) frequently occur. Puffballs
of Rhizopogon species, which have white, homoge-
neous centers, can easily be distinguished from
those of Pisolithus tinctorius by their lack of
peridioles or small sacs of spores within the
context. Recognizing and separating ectomycor-
rhizal species on the basis of root morphology
requires a trained eye, but the different colors
and shapes of ectomycorrhizae can be distin-
guished with practice. Whereas nonmycorrhizal
feeder roots are generally thin, with texture and
color similar to the larger roots, ectomycor-
rhizae usually are swollen, forked or many-
branched, and differently textured and colored
from the rest of the root system.

During quantitative and qualitative seedling
evaluations, a relative measure of the amount of
mycorrhizal occurrence is more useful than iden-
tification of the ectomycorrhizal fungi on a
sample of seedlings. Sampling techniques have
been developed to estimate the proportion of a
seedling's feeder roots that are ectomycorrhizal.
In measured lengths of lateral roots, numbers of
feeder roots with and without ectomycorrhizae are
counted (Anderson and Cordell 1979) • Such labor-
ious examinations may be required for research
studies, but they are impractical for estimates

Figure 7- — Characteristic ectomycorrhizal fungus
fruiting bodies of (a) Laccaria sp., (b)
Hebeloma sp. , (c) Suillus sp. , (d) Rhizo-
pogon sp., (e) Pisolithus tinctorius , and
(f) Thelephora terrestris .

of large quantities of operational seedlings. A
reliable estimate can be determined by visual
examination of seedling root systems that have
been rinsed clean in water. An estimated per-
centage of ectomycorrhizal feeder roots is
assayed to each seedling and averaged for the
whole seedling sample. With experience, a seed-
ling can be evaluated in a matter of seconds.
These estimates provide values that can be com-
pared among samples, inventory dates, or even
different crop years. As nursery management
practices are refined, it becomes possible to
monitor the mycorrhizal component of seedling
quality.

Unlike ectomycorrhizae, the VA endomycor-
rhizal fungi produce no morphological changes or
structures visible to the unaided eye. Endomy-
corrhizae can only be identified by their micro-
scopic hypha and vesicle morphology, and by the
host association in which they occurred. In
bare-root nurseries, seedling stunting, chloro-
sis, and top dieback are often indicators of poor
endomycorrhizal development. Endomycorrhizal
deficiencies may result from soil fumigation or
from fungicide applications that eliminate or
drastically reduce soil populations of the fungi.
Endomycorrhizal deficiencies also occur in new
seedling production areas with insufficient popu-
lations of appropriate endomycorrhizae. Although
endomycorrhizae can be identified and quantified,
monitoring for possible deficiency symptoms
appearing among endomycorrhizal seedings is more
practical.

MYCORRHIZAE NURSERY MANAGEMENT

Endomycorrhizae or ectomycorrhizae in nur-
series can be increased by modifying nursery
management practices, as well as by artificial
mycorrhizal inoculation. Guidelines for mycor-
rhizal nursery management pertain more to main-
taining healthy seedling root systems than to the
requirements of a particular species of mycor-
rhizal fungus. Enhamcement of mycorrhizal fungi
is inseparable from increased seedling quality.
Management for increased mycorrhizal development
is not limited solely to establishing the symbi-
otic structures on roots. One must consider
development and retention of seedling feeder
roots and mycorrhizae from seed sowing to seed-
ling lifting in the nursery and to planting the
trees in the field. Nurserymen, field foresters,
and tree planters must be made aware of the two
symbiotic living organisms they are handling--the
tree seedling and its complement of mycorrhizal
fungi .

Soil and Cultural Factors

NurserjTDen strive to maintain optimal soil
conditions for seedling growth. Having evolved
with their host trees, mycorrhizae generally
require the same moisture, fertility, and pH as
the tree seedlings, but tolerance for extreme or
adverse conditions does vary. Mycorrhizae are
adapted to the full range of forest soils, from

109

heavy clays to coarse sands, but their responses
to nursery practices vary with the soil type.
For example, ectomycorrhizae on southern pine
seedlings in deep sands may have much reduced
tolerance of the systemic fungicide triadimefon
(Bayleton) as compared to ectomycorrhizae occur-
ring in clayey nursery soils. Soil fumigation
with methyl bromide formulations is generally
more effective in lighter, sandy soils than in
heavy clays, which bind the chemical and prevent
complete penetration. Similar interactions
between soil texture and composition and mycor-
rhizae may occur for other cultural practices,
including irrigation, fertilization, and appli-
cation of other pesticides.

Soil pH

The pH of nursery soils has a profound effect
on mycorrhizal establishment and growth. As a
measure of the balance of acid and basic chemical
activity in a soil, pH indicates limitations to
the availability of nutrients, the pattern of
nutrient absorption and exchange in the root
zone, and even the composition of micro-organisms
(mycorrhizal fungi, saprophytes, and soil patho-
gens) in the root zone. Although mycorrhizal
synthesis occurs on trees in soils with wide pH
ranges throughout the world, pH of nursery soils
should approximate the optimum for the tree
species and the forest soil type. For endomy-
corrhizae on hardwoods, Kormanik (I98O) recom-
mended maintaining soil pH between 5 and 6. He
cited a study in which satisfactory endomycor-
rhizal synthesis and sweetgum seedling growth
occurred at pH 4.5 and 5 -5. but not at pH 6.5 or
7.5- Ectomycorrhizae also are usually favored by
slightly acidic soils, and some, such as Pt, are
severely inhibited by soil pH over 6.5. Most
ectomycorrhizal fungi have a pH optimum between
pH 4 and 6 when grown in pure culture, but by
manipulating the amount and chemical formulation
of nutrients, this range can be extended or
shifted to more acidic or alkaline pH optimums.

The indirect effect of soil pH on nutrient
availability in soils may be more important in
mycorrhizae formation than the direct effects of
pH on the fungus (Slankis 1974). All the macro-
nutrients are more available above pH 6. Pt
thrives in nursery soils under standard fertili-
zation regimes, at pH 4.5 to 5.5. and on acid
mine spoils with soil pH as low as 3- Vegetative
inoculum formulations of Pt produced at pH
greater than 6.0 were not as effective as inocu-
lum produced at pH below 6.0 (Marx et al. 1984).
An additional hazard of high soil pH in the pro-
duction of both conifer and hardwood seedlings is
the increased activity of soil pathogenic fungi,
such as Fusarium and Pythium , which cause damping
off and root rot.

Soil Drainage and Moisture

For satisfactory mycorrhizal development and
seedling growth, nursery soils must have adequate
soil drainage but sufficient soil moisture. In

dry soils, free water is unavailable to roots,
and nutrient absorption and exchange stop. How-
ever, irrigation generally maintains adequate
soil moisture for seedling growth. In soils with
excess water, oxygen deficiency inhibits the
growth of both symbiotic fungi and tree roots.
Respiration is greater in mycorrhizal roots than
in noninfected roots. Prolonged flooding pro-
foundly changes root physiology, decreasing
phosphorous fixation, decreasing permeability to
water and nutrients, arresting growth, and even-
tually killing roots (Slankis 1974). Seedlings
grown in poorly drained soils are subject to
damping off and root rot diseases caused by fungi
with spores motile in water, such as Pythium and
Phytophthora. Where drainage is poor, soil con-
ditions must be improved by leveling, subsoiling,
or adding amendments.

Soil Fertility

As with other soil factors influencing my-
corrhizal development, fertility should be main-
tained at levels required for ample host seedling
growth. Excessively high levels of certain nu-
trients, particularly nitrogen and phosphorous,
may change chemical balances within seedling root
systems, limiting mycorrhizal infection. As pH
rises above 6, high phosphorous and nitrogen
levels may be especially discouraging to mycor-
rhizal fungi. With soil pH at or below 6, how-
ever, seedlings grown under high fertility (espe-
cially nitrogen) have produced abundant Pt ecto-
mycorrhizae. Hardwood seedlings grown under high
phosphorous fertility (greater than 200 ppm) have
reduced endomycorrhizal synthesis (10-355^ down
from 40-75/^) without reducing seedling growth.
Kormanik (I98O) recommends maintenance of 75 to
100 ppm phosphorous for good hardwood seedling
and VA mycorrhizal development. Kormanik also
recommends up to 10 applications of nitrogen,
totaling 500 lb/acre, scheduled to capture late
season height growth of hardwood seedlings fol-
lowing root development. Increasing total nitro-
gen from 250 to 500 lb/acre was accompanied by a
50-percent increase in height growth and approxi-
mately a 40-percent increase in root collar diam-
eter of endomycorrhizal sweetgum seedlings,
justifying the added nitrogen cost.

Soil Fumigation

Effective soil fumigation is necessary to
control against weeds, nematodes, insects, and
injurious soil fungi. Unfortunately, fumigation
also kills existing populations of mycorrhizal
fungi. Ectomycorrhizal fungi are quickly replen-
ished by high numbers of windblown spores from
mushrooms and puffballs. Replenishment occurs so
readily in most nurseries, that spring rather
than fall fumigation is required before artifi-
cial ectomycorrhizae inoculations to minimize
competition from these naturally occurring
fungi .

Spread only by physical movement of soil and
water, endomycorrhizal fungi are slow to return

110

to prefumigation levels. VA fungi populations
are highly variable in fumigated areas and build
up in the soil only after one or more crops are
grown. By growing cover crops between soil fumi-
gation and sowing of tree seedlings, endomycor-
rhizal populations are at effective levels for
seedling production. If certain soil pathogens,
such as Cylindrocladium sp. , were not of greater
danger than having insufficient endomycorrhizae ,
soil fumigation should be avoided all together.

Cover Crops

In addition to building up endomycorrhizal
populations, cover crops between seedling crops
rest the soil, increase organic matter content,
and improve soil structure. Crops of corn,
sudex, sorghum, millet, or grasses are effec-
tive in building up VA fungi in the plant roots
and in soil. Winter as well as summer cover
crops will increase endomycorrhizae. Although
sorghum induced highest densities of VA fungal
spores, sweetgum seedlings grown in compartments
planted with corn, millet, sudex, and sorghum
were of comparable quality and size (Kormanik,
Bryan, and Schultz I98O) . Crops with longer
growing seasons have greater potential for root
growth and spore production. Use of any cover
crop after fumigation must be accompanied by
careful monitoring of any chronic soil-borne
disease problems that may occur in particular
nursery soils .

Pesticides

Many pesticides of various types are used in
nurseries, and the effects of individual chemi-
cals on seedling growth or mycorrhizal synthesis
are seldom known. The effects of herbicides and
insecticides on mycorrhizae are particularly
unexplored. However, many effects of commonly
used fungicides have been documented. The fungi-
cides captan and benomyl are recommended for use
in conjunction with operational Pt inoculation of
bare-root nurseries. Metalaxyl (Ridomil or Sub-
due) , an effective fungicide against Phytophthora
root rot, has no deleterious effect on ectomy-
corrhizae on Fraser fir when used at recommended
dosages. Perhaps the most widely used fungicide
in southern pine nurseries is the systemic fungi-
cide, triadimefon (Bayleton) , used to control
fusiform rust. Triadimefon seed treatments which
provide rust control through southern pine seed-
ling emergence, have no negative impact on natu-
rally occurring or artificially-introduced ecto-
mycorrhizal fungi. However, foliar applications
applied three to four times during the rust
season (May- June) suppress ectomycorrhizal devel-
opment until late in the growing season. Pt
ectomycorrhizae are particularly susceptible to
this fungicide. Normally, by lifting time, natu-
rally occurring ectomycorrhizae, mostly
Thelephora terrestris , have recolonized the root
system. Negative impact on seedling quality is
hotly debated, but the effects on mycorrhizae are
well substantiated. Any and all pesticides,
prior to operational use in nurseries, should be

evaluated for their effects on mycorrhizal
development as well as seedling growth.

Shading

Shade-tolerant conifer seedlings require some
degree of physical shading. Too much shading
reduces photosynthesis and soil temperatures to
the degree that mycorrhizae cannot form. The
optimum level of shade must be found that pro-
tects seedlings from scorching but does not
inhibit mycorrhizae.

Root Pruning

At the proper depth and distance from seed-
lings, root pruning stimulates formation of com-
pact root systems and increased mycorrhizal
development. Injury of the root tips initiates
greater carbon allocation to the root system,
which causes the increased root growth. This
practice increases the amount of mycorrhizal
feeder roots proximal to the seedling stem,
effectively increasing the amount of mycorrhizae
that will be retained with the seedling during
lifting and handling.

Seedling Lifting, Storage, and Planting

Special care must be taken during all stages
of seedling handling to maintain sufficient root
systems and mycorrhizae. Mycorrhizae are deli-
cate structures. They can be ripped off and left
behind in seedling beds during lifting, desic-
cated in storage, or cut off prior to field
planting. For sustained seedling quality, lift-
ing and handling techniques must be modified to
minimize damage to feeder roots and mycorrhizae.
Stripping of roots adds severe negative impacts
on seedling field performsmce (Marx and Hatchell
1986) . Full bed seedling harvesters are less
destructive than single- or double-row lifters .
Condition of the root systems should be checked
during the entire lifting process; even slight
reductions in tractor speed can greatly reduce
damage to the roots as seedlings are lifted.

During transfer of seedlings from the field
to the packing room and at all other times when
seedlings are handled, special care is required
to avoid drying of the roots by exposure to wind
and sun. The procedure by which seedlings are
packed influences their ability to endure storage
and survive field planting. If extended storage
is required, Kraft paper bags with a polyethylene
seal will maintain seedling moisture better than
seedling bales. Cold storage is vital to slow
seedling respiration. Studies comparing packing
material have determined that seedling survival
is better when peat moss, clay, or inert super-
absorbents are used rather than hydromulch
(Cordell, Kais, Barnett, and Affeltranger 1984).
The material should be distributed through the
bag, not simply dumped at the bottom or top.
Better results are obtained when all root systems
are coated or at least in contact with the pack-

Ill

ing material. Numerous studies have documented
the effects of long-term storage on seedling
quality. For most tree species and their mycor-
rhizae, storage for 2 to 6 weeks is not harmful.
Beyond the threshold for each species, however,
significant negative effects can occur.

Seedling quality is vulnerable to any one or
more limiting factor. Even if quality is main-
tained through seedling growth, lifting, and
storage, it could still be severely reduced by
improper transportation to the planting site or
rough handling during planting. Tree planters
should understand proper planting methods and the
reasons for them. Where possible, seedlings
should be transported under refrigeration. If
that is not possible, they should be covered and
stacked with spacers to avoid high temperature
buildup inside the seedling containers. For
machine or hand planting, root pruning at the
planting site should be avoided because it elimi-
nates carefully nurtured feeder roots and mycor-
rhizae. High temperature, high winds, and low
humidity kill feeder roots and mycorrhizae very
rapidly. The first priority in planting should
always be to maintain seedling viability and
vigor. The rate at which acres are planted is of
no consequence if the seedlings do not survive.

Ectomycorrhizal Fungus Inoculations

Ectomycorrhizal Fungus Inoculum

Until recently, artificial inoculation of Pt
or any other ectomycorrhizal fungus species was
limited because procedures, commercial fungus
inoculum, and necessary equipment were not read-
ily available to nurserymen. The USDA Forest
Service has been cooperating with several private
companies to develop different types of commer-
cial ectomycorrhizal inoculum, along with equip-
ment and procedures needed for inoculating bare-
root and container-grown seedlings. In addition
to Pt ectomycorrhizal inoculum, strains of
Hebeloma sp., Laccaria sp. , and Scleroderma sp.
are currently available. The types of Pt inoc-
ulum that are available are vegetative inoculum
from Mycorr Tech, Worthington, Pennsylvania,
spore pellets, spore-encapsulated seeds, and bulk
spores from either International Forest Tree Seed
Co., Odenville, Alabama, or SouthPine, Inc.,
Birmingham, Alabama. A nursery seedbed appli-
cator (Fig. 8) has been developed to accurately
place Pt vegetative inoculum in seedbeds prior to
sowing in bare-root nurseries. Inoculum is
applied in bands under seed rows at desired
depths (Fig. 9)- Use of the applicator has
reduced the amount of vegetative inoculum needed
by 75 percent and reduced time and labor require-
ments as compared to broadcast application.

Inoculum Costs

There is a wide range in the cost of commer-
cial Pt inoculum (Table 1). Cost of the each
inoculum type also varies with such factors as

Figure 8. — A commercially available machine

applies bands of commercial Pt vegetative
inoculum to a bare-root nursery seedbed.

Figure 9-~~Diagram of a bare-root nursery seed-
bed shows bands of Pt vegetative inoculum
under seedling rows in root zones.

Table 1 . --Commercial Pt inoculum costs.

Inoculum cost per

inoculum type

1,000
seedlings

planted
hectare

planted
acre

Vegetative
mycelium

$10.00

$17.94

$7.26

Spore-
encapsulated
seeds

$ 2.22

$ 3.98

$1.61

Spore pellets

$ 2.75

$ 4.93

$2.00

Double-screened
bulk spores

$ 0.43

$ 0.77

$0.31

Cost estimates are for loblolly and2slash
pine bare-root gurseries (269 seedlings/m or
25 seedlings/ft ) and forest plantings (1.8 x
3.0 m or 6 X 10 ft. spacing; 1,79^ trees/ha. or
726 trees/ac.) in the Southern United States.

Double screening is required for even
flow through spray nozzles. Standard bulk spores
are only screened once.

112

nursery seedling density, seed size for spore-
encapsulated seeds, and field planting spacing.
In 1987, the Pt vegetative inoculum costs for
bare-root nurseries per unit of forest product
were reduced 25 percent by increasing nursery
seedbed inoculation efficiency, improving effec-
tiveness of inoculum, and decreasing application
rates. The vegetative mycelium is sold on a
volume (liter) basis, while the spore inocula are
all sold on a weight (pound) basis.

Inoculation Procedures

Operational procedures vary among the diff-
erent commercial Pt inoculum types, but with any
inoculum, the biological requirements of a second
living organism are added to those of the seed-
ling. Special precautions are necessary for
shipping, storing, and handling the Pt inoculum,
as well as for lifting, handling, and field
planting of seedlings. For successful Pt inocu-
lation in bare-root seedbeds, populations of
pathogenic and saprophytic fungi and native ecto-
mycorrhizal fungi that may already be established
in the soil must be reduced by spring soil fumi-
gation. Prior to spring sowing, vegetative inoc-
ulum can be broadcast on the soil surface and
incorporated into the fumigated seedbeds or it
can be machine-applied with greater effectiveness
and efficiency. For container-grown seedlings,
vegetative inoculum can be incorporated into the
growing medium before filling the containers or
placed at selected depths in the growing medium
in the container. Bulk spores can be sprayed,
drenched, or dusted onto growing medium for con-
tainerized seedlings and onto seedbeds in bare-
root nurseries. Spore pellets can either be
incorporated into the growing medium or seedbed
soil, or they can be broadcast on the soil sur-
face, lightly covered, and irrigated. Spore
pellets have been applied at several nurseries
with a standard fertilizer spreader (Fig. 10) .
Spore-encapsulated seeds can be sown by conven-
tional methods. A major disadvantage of the Pt
spore inoculum is the absence of a reliable means
of determining or controlling spore viability.
Consequently, Pt ectomycorrhizal development has
been considerably less consistent and effective
with spore inoculum than with vegetative
inoculum.

Figure 10. — Commercially available Pt spore

pellets are applied to a nursery seedbed
with a standard fertilizer applicator.

MIUJON SEEDUNGS

6 I

5 ■

4 -

3 -

2 -

1 -

1984 1985 1986 1987

Figure 11 . --Increased Pt-inoculated custom
seedling production in bare-root and
container seedling nurseries, 1984-87.

Operational Applications

The demand for Pt- tailored nursery seedlings
has significantly increased during the past 4
years, despite the added costs and financial dif-
ficulties that most forestry agencies are cur-
rently experiencing. Since 1984, annual demand
for tailored seedlings has increased 10- fold from
0.5 million to 5 million seedlings (Fig. 11).
During the spring of 1986, Pt vegetative inoculum
was operationally applied at 10 bare-root nur-
series in the Southern and Central United States.
Approximately 2 million seedlings of 9 conifer
and 1 hardwood species were produced. In addi-
tion, over 1 million pine seedlings were inocu-
lated with spore pellets. During the spring of
1987, Pt vegetative inoculum was applied at five
bare-root nurseries in the Southern and Central
United States. More than 3 million seedlings of
five conifer and one hardwood species were inocu-
lated. More than 2 million seedlings are being
produced at a South Carolina State nursery for
the USDA Forest Service, Savannah River Forest
Station, and the United States Department of
Energy. This represents the largest single
application of an ectomycorrhizal fungus in a
forest tree nursery to date. Over 2 million
additional pine seedlings were inoculated with
spore pellets at two bare-root nurseries in North
Carolina and South Carolina and a container seed-
ling nursery in Alabama.

Endomycorrhizal Fungus Inoculations

Although the technology required to produce
VA mycorrhizal inoculum and to inoculate soils
and plants is available and in use on certain
agricultural and orchard crops that are highly
dependent on endomycorrhizae, artificial inocu-
lation of forest tree seedlings is not generally
feasible. For most tree species, the phosphorous
threshold is low enough that increased fertili-
zation can remedy the effects of endomycorrhizal
deficiencies. In addition, within several

113

months, indigenous VA fungi on most reforestation
sites colonize root systems of seedlings that
were deficient in endomycorrhizae at the nursery.
However, artificial inoculation may be beneficial
if continued endomycorrhizal deficiencies and
subsequent reductions in seedling quality occur
at a nursery despite modifications in fertiliza-
tion, fumigation, and crop rotation.

Different methods of artificial inoculation
with variable potential benefits may be utilized.
Nurserymen can add endomycorrhizal forest soils
to the nursery soil, add soil from an area previ-
ously used to produce endomycorrhizal seedlings,
or build up VA fungi populations through cover
cropping. Soil or roots from the cover crop area
can be spread over a deficient area and tilled
into the soil. A potential problem with any of
these methods is that soil pathogens can be
introduced or increased by the same processes
that introduce or increase VA fungi. Commer-
cially available pot cultures of endomycorrhizal
hosts grown under aseptic conditions can provide
potentially cleaner and more effective inoculum
consisting of soil and roots. Various types of
VA fungal inocula are currently produced by NPI
(Native Plants, Inc.), Salt Lake City, Utah
84108. This endomycorrhizal "starter" inoculum
can be used to introduce appropriate VA fungi
into fumigated or naturally deficient soils.
Cover cropping can then be used to build up the
VA fungal populations to effective levels for the
production of endomycorrhizal seedlings.

CONCLUSION

Symbiotic relationships between tree seed-
lings and mycorrhizal fungi are the rule in
nature. Conifer and hardwood nursery seedlings
require adequate quantities and quality of either
ecto- or endomycorrhizae to meet seedling quality
standards. Minimum quantities or amounts of
mycorrhizae are required to provide adequate
field survival and growth. For southern pines
produced in bare-root nurseries, this minimum
ectomycorrhizae quantity has been established at
35 percent of the total seedling feeder roots on
90 percent or more of the seedlings. It should
be emphasized that this 35 percent must be pres-
ent when the pine seedlings are planted in the
field. The quality of ectomycorrhizae for a
planting site depends on the host tree-fungus
species combination; optimum combinations can be
produced by inoculating seedlings for specific
applications, such as mineland reclamation. Cus-
tom production of mycorrhizal seedlings has been
incorporated into bare-root and container nursery
operations. The quality of mycorrhizae and of
seedlings can also be improved through careful
management of existing ecto- or endomycorrhizae.

Regardless of the selected alternatives, nur-
serymen, field foresters, and tree planters must
be aware that they are dealing with two symbiotic
living organisms — the tree seedling and the my-
corrhizal fungus. Both must be nurtured to pro-
vide seedlings of the highest quality for field

forestation. The tree seedling-mycorrhizal fun-
gus symbiotic relationship is an integral compo-
nent of nursery seedling production. Any esti-
mates of seedling quality that exclude quanti-
tative and qualitative mycorrhizal assessments
are incomplete and unrealistic.

LITERATURE CITED

Anderson, Robert L., and Charles E. Cordell.

1979 • How to: recognize and quantify ecto-
mycorrhizae on conifers. USDA Forestry
Bulletin SA-FB/PB. 9 p. State and Private
Forestry, Atlanta, Ga.

Cordell, C.E., A.G. Kais , J. P. Barnett, and C.E.
Affeltranger. 1984. Effects of benomyl
root storage treatments on longleaf pine
seedling survival and brown-spot disease
incidence, p. 84-88. In Proceedings of the
1984 southern nursery conferences. [Western
Session: Alexandria, La. June 11-14, I985].
USDA Forest Service, Atlanta, Ga.

Cordell, Charles E. I985. The application of
Pisolithus tinctorius ectomycorrhizae in
forest land management, p. 69-72. In
Proceedings of the 6th North American
conference on mycorrhizae. [Bend, Oreg.
June 25-29, 1984]. Oregon State University,
Corvallis, Oreg.

Hatchell, Glyndon E. 1985- Nursery cultural

practices affect field performance of long-
leaf pine. p. 148-156. In Proceedings of
the international symposium on nursery
management practices for the southern pines.
[Montgomery, Ala. August 4-9, 1985].
Alabama Agricultural Experiment Station,
Auburn University, Ala.

Kais, A.G., G.A. Snow, and D.H. Marx. I98I .
The effects of benomyl and Pisolithus
tinctorius ectomycorrhizae on survival and
growth of longleaf pine seedlings. South.
J. Appl. For. 5(4) :189-195-

Kormanik, Paul P. I98I . Effects of nursery
practices on vesicular-arbuscular mycor-
rhizal development and hardwood seedling
production, p. 63-67. In Proceedings of
the 1980 southern nursery conference. [Lake
Barkley, Ky. September 2-4, 198O] . Tech-
nical Publication SA-TP 17 . USDA Forest
Service, Region 8, Atlanta, Ga.

Kormanik, Paul P. I985. Effects of phosphorous
and vesicular-arbuscular mycorrhizae on
growth and leaf retention of black walnut
seedlings. Can. J. For. Res. 15:688-693-

Kormanik, Paul P. 1986. Lateral root morphology
as an expression of sweetgum seedling
quality. For. Sci. 32(3) : 595-604.

Kormanik, Paul P. , W. Craig Bryan, and Richard C.
Schultz. 1980. Increasing endomycorrhizal

114

fungus inoculum in forest nursery soil with
cover crops. South. J. Appl. For.
4{3):151-153.

Kormanik, Paul P., Richard C. Schultz, and

William C. Bryan. I982. The influence of
vesicular-arbuscular mycorrhizae on the
growth and development of eight hardwood
tree species. For. Sci. 28(3) :531-539-

Marx, D.H. I98O. Ectomycorrhizal fungus inocu-
lations: A tool for improving forestation
practices, p. 13-71. In Tropical mycor-
rhiza research (Mikola, P. ed) , Clarendon
Press, Oxford.

Marx, D.H., C.E. Cordell, D.S. Kenney, J.G.

Mexal, J.D. Artman, J.W. Riffle, and R.J.
Molina. 198't. Commercial vegetative inocu-
lum of Pisolithus tinctorius and inoculation
techniques for development of ectomycor-

rhizae on bare-root tree seedlings. For.
Sci. Monogr. No. 25. 101 p. Society of
American Foresters, Washington, D.C.

Marx, D.H.. J.L. Ruehle, D.S. Kenney, C.E.

Cordell, J.W. Riffle, R.J. Molina, W.H.
Pawuk, S. Navratil, R.W. Tinus , and O.C.
Goodwin. I98I. Commercial vegetative
inoculum of Pisolithus tinctorius and
inoculation techniques for development of
ectomycorrhizae on container-grown tree
seedlings. For. Sci. 28(2) : 373-400.

Marx, Donald H. 1977 • The role of mycorrhizae
in forest production. Tappi 60:151-l6l.

Marx, Donald H. , and Glyndon E. Hatchell. 1986.
Root stripping of ectomycorrhizae decreases
field performance of loblolly and longleaf
pine seedlings. South. J. Appl. For.
10:173-179.

115

Integrated Pest Management in Forest Nurseries^

T. H. Filer, Jr. and C. E. Cordell^

Abstract. --INPM techniques and procedures provide the
necessary information to assist nursery managers in planning
the most effective practices to produce quality seedlings.
An integrated program that considers the following factors
will minimize losses from diseases, insects, and weeds:
site selection, fumigation, crop rotation, cover crops, sow-
ing date, fertilization, irrigation, seedbed density, and
chemical and biological control methods.

INTRODUCTION

Conservation reserve and other tree planting
programs have caused an accelerated rate of refor-
estation in the United States, which has caused an
increase in seedling production. New state and
industry nurseries are being established, as well
as old ones being expanded. More than 80 industry,
state, and federal nurseries in the South produce
over 1 billion seedlings annually. This represents
over 75% of the total annual bare-root production
in the United States. Nurseries grow a wide vari-
ety of both conifers and hardwood species.

Increased production and tree species confront
nursery managers with a wider array of potential
pest problems . The high value of genetically
improved seedlings has significantly increased the
impact of pest problems.

Seedling quality represents the most important
economic aspect of forestation. However, seedling
cost will average less than l^/c of total plantation
establishment cost per acre. To meet future wood
demands, high quality and quantity of tree seed-
lings must continue to be available to the forest
manager .

Major pest problems in the nursery are an
exception rather than the rule. When major
problems do occur, nursery managers can utilize
integrated pest management practices.

The integration of suitable techniques and
procedures into one concerted, harmonious effort is
needed for effective, efficient control of nursery
pests .

Integrated Nursery Pest Management (INPM) is
defined as the reduction of pest problems in the
nursery by employing decisions, plans, and a combi-
nation of management procedures in a coordinated
pest management program. This system, to be suc-
cessful, requires a systematic, interdisciplinary
approach from such related disciplines as soil
science, silviculture, forest pathology, entomol-
ogy, and weed science. Emphasis must be placed on
pest prevention, containment, and exclusion.

Nursery pest management practices are closely
related to and must be harmoniously used with pre-
scribed cultural practices to be practical and
effective. The selection of the most effective,
practical, and environmentally safe combination of
INPM practices for target pest problems is the key
to successful pest management.

PREVENTION

An effective quarantine program will prevent
the transfer and spread of pathogens, nematodes,
insects, and weeds into nursery and field forest-
ation areas. These pests may be present on seeds,
seedlings, soil, water, equipment, or personnel.
Preventive measures represent the most effective
and efficient pest management practice.

Paper presented at the Intermountain
Nursery Association Meeting, Oklahoma City, August
10-142 1987.

Plant Pathologist, USDA Forest Service,
Southern Forest Experiment Station, Stoneville, MS,
and Plant Pathologist, USDA Forest Service, Forest
Pest Management, Region 8, Asheville, NC.

PEST DETECTION, DIAGNOSIS, AND EVALUATION

Early pest detection, combined with rapid
diagnosis of problems, is a prerequisite to suc-
cessful nursery pest management. Rapid diagnosis
will permit the selection and timely application of
control procedures before the pest becomes
unmanageable .

116

NURSERY SITE SELECTION

SOIL AND WATER PH

Selection of the nursery site is the most
important cultural practice for consideration in
the nursery pest management plan. Select new
locations or expand existing nurseries only after
considering the following factors and their rela-
tionship to pest management: soil types, texture,
pH, past land use, presence of harmful pests, ade-
quate supply of clean water with proper pH. The
soil type for most tree species should be of a
coarse texture, primarily sand with some silt and a
low clay content. The soil profile should not have
any impermeable subsoil. This type of soil pro-
motes good tillage, fumigation, and drainage. Pre-
emergence damping-off, caused by soil-borne fungi,
is less severe in coarser soil with good drainage.
The pH of soil and irrigation water can influence
the development of soil-borne diseases. Pre- and
post-emergence damping-off diseases often occur in
conifers when the soil pH exceeds 6.0.

CROP ROTATION

Crop rotation is used in INPM programs to
reduce seedling losses from fungi, insects, nema-
todes, and weeds. The pests often become serious
problems when continuous seedling production is
practiced without rotation. Alternating suscepti-
ble and nonsusceptible crops in proper sequence
will minimize seedling losses. The alternation of
cover crops with seedling production is standard
practice in many forest tree nurseries.

COVER CROPS

Cover crop species vary in their susceptibil-
ity to different root rot pests. Corn, peas, soy-
beans, and sorghum are susceptible cover crop hosts
for charcoal root rot of conifers (Seymour and
Cordell 1979)- Alfalfa, soybeans, and other
legumes are susceptible to the Cylindrocladium root
rot fungus of hardwoods (Cordell and Skilling
1975).

To allow for adequate decomposition, cover
crops should be plowed under a minimum of 2 months
before fumigation. Non-decomposed organic matter
will absorb large quantities of fumigants, thereby
reducing pest control . Organic matter amendments
may reduce root pathogens because increased organic
matter promotes high populations of saprophytes and
soil organisms that compete with root pathogens.

ORGANIC MATTER AMENDMENTS

Annual applications of organic matter to nur-
sery beds help to improve tilth, nutrient, water
retention, and soil aeration. However, precautions
are required concerning the type and composition.
The addition of fresh sawdust or pine bark may have
adverse effects on tree seedling development by
changing the carbon/nitrogen ratio of the seedbed.
Micro-organisms tie up the available nitrogen and
the seedlings suffer from nitrogen deficiency.

Soil pH, excessively high or low, influences
the severity of diseases caused by soil-borne
fungi. The addition of elemental sulfur is useful
to lower soil pH and reduce disease losses such as
damping-off on conifer and hardwood seedlings. The
addition of lime will increase the soil pH to more
desirable levels. The pH of irrigation water can
be lowered by metering sulfuric or phosphoric acid
into the irrigation system. Desirable soil and
water pH levels range between 5-0 and 6.0.

SEEDBED SOWING DATES

Minimize seedling losses from soil-borne
pathogens by selecting the proper planting date.
Cold, moist soils are conducive to growth and
development of Pythium and Phytophthora fungi that
cause pre- and post-emergence damping-off of seed-
lings (Filer and Peterson 1975) • A delay in spring
seeding until soil temperatures are favorable for
seed germination will often avoid losses from
damping-of f f ungi .

In the southern states , an equally serious
problem is high soil surface temperature in late
spring, which causes sun scald of young seedlings.
Fall sowing is an alternative choice to avoid sun
scald problems of several hardwood species.

SEEDBED DENSITY

The correct seedbed density will reduce cer-
tain pest problems. Seedbeds planted too dense,
increasing competition for the available soil
nutrients and water, will result in reduction in
seedling growth and vigor. Poor seedling vigor
increases susceptibility to diseases and insects.
High seedbed density also reduces air circulation,
which results in more foliage diseases. The
increased demand for seedlings to meet accelerated
reforestation programs suggests a possible trend to
denser nursery seedbeds.

MULCH FUMIGATION

Mulches, such as pine needles and grain straw,
should be fumigated to eliminate pathogenic fungi,
weed seeds, and nematodes. Sanitation by fumiga-
tion prevents unnecessary introduction into the
seedbed of pathogenic fungi, insects, and other
pests. If pine needles, etc., are used for mulch,
fumigate under tarp with methyl bromide 98% -
chloropicrin 2% or methyl bromide 67% - chloro-
picrin 33% at the rate of 1 pound per cubic yard of
mulch. Aerate the mulch at least 48 hours before
it is applied to nursery beds.

FERTILIZATION

Fertilizer composition, rate, timing, and
application methods can have adverse or beneficial
effects on disease problems. Sub-optimal rates,
inadequate formulation, and improper use of fer-

117

tilizer often results in seedling stunting, yel-
lowing, poor root development, and mortality.
Excess nitrogen application in early spring in
soils deficient in calcium and phosphorus may
increase seedling damage by damping-off fungi.
Excessive levels of phosphorus (200 lbs. available
P^Oj^ per acre) will inhibit both naturally
occurring and artificially inoculated ecto- and
endomycorrhizae on conifer and hardwood seedlings.

CHEMICAL TREATMENTS

Chemical treatments involve a variety of pre-
and post-planting pesticide applications. Although
the use of pesticides is considered a significant
component of INPM, pesticides should be used only
when other INPM procedures are not available or
have failed to give satisfactory control of pests.

SANITATION

Sanitation is an important practice in nursery
pest management to prevent the spread of pest prob-
lems within the nursery and to field plantings.
The practice includes roguing diseased seedlings
and weed species in seedbeds. Existing susceptible
windbreak species may require elimination to avoid
build up of fungus inoculum and insects. Weed-free
riser lines and fence roads will help reduce the
spread of weed seeds, fungi, and insects into the
nursery bed.

SEEDLING GRADING AND CULLING

Grading of seedlings before packing will mini-
mize the transport of pest-infested seedlings to
the planting site. Conspicuous root, stem, and
foliage diseased seedlings should be culled in the
packing shed. Particular seedling grading and
culling efforts should be afforded potentially sig-
nificant pest problems, such as the root rots
(charcoal - Macrophomina phaseolina, cylindro-
cladium - Cylindrocladium spp., and phytophthora -
Phytophthora spp.) and southern pine fusiform rust
(Cronartium quercuum f. sp. fusi forme) (Rowan,
Cordell, and Affeltranger I98O) . Although it is
costly, nursery managers who have eliminated seed-
ling grading in packing sheds should consider rein-
stating this practice when severe pest problems
appear.

BIOLOGICAL AGENTS

Biological techniques represent one of the
most desirable INPM practices, but effective pest
control procedures are very limited for nursery
production. Perhaps the best example of biological
application in nurseries involves the artificial
inoculation and/or management of selected mycor-
rhizal fungi to increase seedling quality (Cordell
and Webb I98O) .

Most micro-organisms in the soil are either
saprophytic or nitrification agents. Some micro-
organisms are antagonistic or competitive with
soil-borne pathogens. Without sufficient popula-
tions of these beneficial microflora, organic
matter decomposition and nutrient fixation are
greatly impeded. Most of the organisms are the
pioneer colonizers of recently fumigated soil.
Their presence is essential for the conversion of
ammonia nitrogen to the nitrate form, which can be
used by seedlings.

SOIL FUMIGATION

Soil fumigation is the most effective chemical
control technique for a variety of soil-borne nur-
sery pests, including soil fungi, insects, nema-
todes, and weeds. The most effective soil fumi-
gants are the methyl bromide-chloropicrin formula-
tions. The methyl bromide 67% - chloropicrin 33/^
formulation is most effective in controlling root
pest problems and certain weeds and grasses, such
as nutsedge. Additional benefits from thermal
energy can be obtained by allowing the tarp to
remain on the seedbed after fumigation for 10 to ik
days or until the beds are prepared for planting.

SEED TREATMENT

In southern nurseries, most pine seeds are
coated with Thiram fungicide-latex sticker to
retard damping-off and repel birds. Thiram at the
rate of 2 pounds per 100 pounds of seed is commonly
used. For the control of fusiform rust in southern
nurseries, the systemic fungicide triadimefon
(Bayleton) is presently being used as either a
liquid seed soak or dry powder coating to protect
the young pine seedlings during the first few weeks
following emergence (Rowan and Kelley I983) .

PROTECTIVE FOLIAGE SPRAYS

There is often a need for protective foliage
sprays to control foliage diseases and insects on
both conifer and hardwood seedlings (Smyly and
Filer 1973)- However, only a relatively few chemi-
cals are available for effective and practical
control of foliage pest problems. Effective con-
trol of foliage diseases requires complete and con-
tinuous coverage of the susceptible foliage during
the fungus infection period when using a protective
contact fungicide. However, effective control of
fusiform rust can be obtained with reduced applica-
tions (i.e., 3 to 4 well-timed sprays) of the sys-
temic fungicide triadimefon (Rowan and Kelley
1983).

118

REFERENCES

Cordell, Charles E. and Darrell D. Skilling. 1975.
Cylindrocladium root rot. p. 23-26. In:
Forest nursery diseases in the United States.
Agric. Hand. No. 470. U.S. Department of
Agriculture, Washington, DC.

Cordell, Charles E. and David M. Webb. I98O.

Pt...a beneficial fungus that gives your trees
a better start in life. Gen. Rep. SA-GR 8.
16 pp. USDA Forest Service, Southeastern
Area, Atlanta, GA.

Filer, T.H. , Jr. and Glenn W. Peterson. 1975.
Damping-off. p. 6-8. In: Forest nursery
diseases in the United States. Agric. Hand.
No. kjO. U.S. Department of Agriculture,
Washington , DC .

Rowan, S.J., C.E. Cordell, and C.E. Af feltranger .
1980. Fusiform rust losses, control costs,
and relative hazard in southern forest tree
nurseries. Tree Planters' Notes 31(2) :3-8.

Rowan, S.J. and W.D. Kelley. I983. Bayleton for
fusiform rust control - an update of research
findings, p. 202-211. In: Proceedings of the
1982 southern nursery conference. Tech. Pub.
r8-TP4. USDA Forest Service, Region 8,
Atlanta, GA.

Seymour, CP. and C.E. Cordell. 1979- Control of
charcoal root rot with methyl bromide in
forest nurseries. South. J. Appl. For.
3(3) :104-108.

Smyly, W.B. and T.H. Filer, Jr. 1973- Benomyl

controls Phomopsis blight on Arizona cypress
in a nursery. Plant Dis. Rep. 57(l):59-6l.

119

The USPS Reforestation Improvement Program^

W. J. Rietveld, Peyton W. Owston, and Richard G. Miller^

Abstract. — The program applies state-of-the-art equip-
ment and methods to input weather, culture, growth, quality,
handling, and field data into a computerized database at
each Forest Service nursery. The ultimate goals of the
program are to increase efficiency, improve reforestation
success, and lower costs.

INTRODUCTION

The Reforestation Improvement Program (RIP)
is a combined effort of the three divisions of the
USDA Forest Service — National Forest System,
Research, and State & Private Forestry — to
improve nursery seedling quality and plantation
survival and growth. The concept is to use state-
of-the-art data logging and computer technology
to monitor selected seedlots and determine the
relationships among environmental conditions,
nursery culture, seedling handling, seedling
characteristics, and performance after outplanting.
This information will be used to refine nursery
and reforestation practices, develop a continuing
quality control system, and identify knowledge
gaps that require research.

Following the Seedling Quality Workshop at
Oregon State University in 1984, representatives
from the three divisions of the Forest Service
discussed the agency's nursery program and the
research needed to improve the production of
quality bareroot stock. In January 1985, a team
of nursery managers and research scientists
developed a draft proposal to implement RIP. The
final proposal was approved, all 11 Forest Service
nurseries agreed to participate, and plot estab-
lishment got underway by spring 1986. This paper
describes the objectives, procedures, and current
status of the program.

^Paper presented at the Intermountain Forest
Nursery Association Meeting, Oklahoma City,
Oklahoma, August 10-14, 1987.

^W. J. Rietveld is Research Plant Physiolo-
gist, North Central Forest Experiment Station,
Rhinelander, WI; Peyton W. Owston is Research Plant
Physiologist, Pacific Northwest Forest and Range
Experiment Station, Corvallis, Oregon; Richard G.
Miller is Nursery, Tree Improvement and Genetics,
National Fbrest System, Washington, D.C.

JUSTIFICATION

RIP was begun at this time for several
reasons. The National Forest Management Act of
1976 requires that the successes and failures in
our reforestation program be clearly documented
and reported to Congress. Responsibility for
successful reforestation has been included in
line officers' performance standards. We are
making more detailed evaluations of plantation
survival and growth, and the results of these
evaluations have dramatically increased the
visibility of our reforestation program. The
"Productivity Improvement Analysis of Reforesta-
tion" report published in 1983 states that a 10-
percent reduction in reforestation failures in
the National Forest System would save $2,624,000
annually and that a 50-percent reduction would
save more than $13,000,000 annually. Assuming at
least a 10-percent improvement in reforestation
success, the program is easily justified on a
purely economic basis. This is, of course,
desirable, but we feel that the public image and
professional reasons for improving reforestation
success are even more important.

MAKING A CASE FOR MONITORING

Quality monitoring is done in most industries
where market competition, liability, and reputa-
tion are important factors. In our "industry",
the reasons for monitoring are (1) our desire to
refine and improve, (2) our pride and reputation,
and (3) our accountability. Beyond these com-
pelling reasons, monitoring is impetus for pro-
fessional growth. Without recording our inputs
and their effects, our expertise grows slowly,
because we have no clear records of the fac-
tors that contributed to our successes and
failures. With monitoring implemented we can
learn from both our successes and our failures,
and readily pass that expertise on to our associ-
ates and successors.

Many plantation failures are difficult if
not impossible to explain with the data presently

120

collected. We simply do not know if the problems
are occurring at the nurseries, during shipping
and handling, during planting, or if they are
due to site factors or lack of seedling adapta-
tion. As always, more research is needed to
provide answers, but research may not be enough.
Presently, the minds of experienced nursery
managers and foresters are the databases that
hold the wisdom gleaned from years of experience.
Two unavoidable problems with this tradition
are (1) the memory is volatile, and (2) the data-
bases eventually transfer or retire. To progress
from here, we need to develop computerized data-
bases to store the volumes of existing and future
data and efficiently put them at our disposal.
Once a fairly complete database is developed
for each nursery, and research has adequately
filled in the important gaps in our knowledge,
we will be in a position to attain higher level
goals such as: (1) tailoring culture to unique
conditions within nurseries and to individual
species and seedlots, (2) identifying and mani-
pulating critical factors that most affect
planting stock quality, (3) developing an effec-
tive system to evaluate planting stock quality
and predict field performance, (4) developing
planting stock and site preparation prescriptions
for individual sites, and (5) developing computer
models for the entire reforestation process.

Some of the latest developments in refores-
tation science illustrate these points. There
is a trend towards specific nursery culture of
individual seedlots. Jenkinson (1980) has
developed time windows for lifting several major
timber species and specific seed sources at
individual nurseries. Lifting seedlings outside
these windows results in reduced survival and
growth, and in the worst case, plantation fail-
ure. The Weyerhaeuser Company 3 has led the way
in growing seedlings by family (seed collected
from a clone in a seed orchard), observing
growth response to cultural treatments, and
grouping families with similar growth into
"response groups". Cultural treatments are then
tailored to each "response group" to grow seed-
lings to desired specifications. This increasing
sophistication brings increasing complexity and
the need for more detailed record keeping, a task
that computers can help us with nicely.

The following organizational structure was
developed for RIP in order to maintain communica-
tion and continuity:

Data from
Recording Equipment and Hand Entry

Summaries

Raw Data

Archive at National
Computer Center

Graphics
Hardcopy

Archive
at Nurseries

Participating Units
and Interested Parties

A national steering committee monitors the
overall program and modifies it as necessary.
The program coordinator facilitates installation
of the monitoring system, and implementation of
data collection, summarization, and archival.
A scientific analysis team (SAT) was created to
select appropriate seedling measurement equipment
and techniques, develop data collection and
analysis procedures, and provide feedback and
recommendations to individual nurseries. The
team will evaluate the data from a research
perspective and identify specific problem areas
that need additional research.

Pathologists from the participating Regions
will conduct pathogen and mycorrhizae analyses.
National Forests and Ranger Districts interested
in participating in the outplanting phase were
identified before specific seed sources were
selected for monitoring. The program has also
arranged for a local research scientist to provide
guidance for each nursery, a technician available
by phone to provide support and spare parts for
instrumentation problems, a software developer to
prepare specialized methods to collect, summarize,
graph, and archive RIP's data, and a technician
to help with data processing.

PARTICIPANTS AND ORGANIZATION

All 11 Forest Service nurseries are parti-
cipating in the program. The nurseries are the
center of RIP and the principal benefactors.
The initial level of commitment at each nursery
is to monitor three successive crops of planting
stock of two seedlots of one species, and to
establish two field plots on different sites.

^Personal communication with Dr. William C.
Carlson, Tree Physiologist, Weyerhaeuser Co.,
Southern Forestry Center, Hot Springs, AR 71902.

EXPECTED BENEFITS

Benefits will increase each year as we
monitor new seedlots, encounter different weather
conditions, modify cultural practices, and accumu-
late information on field performance. Expected
short- and long-term benefits are as follows:

Short-term (1 to 5 years)

1. Installation and implementation of state-of-
the-art equipment and methods at the nurseries
to monitor weather, culture, growth, quality,
handling, and field variables, and efficient-
ly summarize and retrieve the data on a
computerized database at each nursery.

121

Development of a standardized system for
collecting and analyzing nursery data to
facilitate interchange of information and
technology among nurseries, research units,
and National Forests.

Increased awareness of seedling biology
through tracking of seedling performance
from seed to site.

Identification of stages in stock production,
handling, shipping, and planting where
quality is lost, so that nursery managers,
foresters, and researchers can focus their
efforts on the most critical areas. Some
immediate improvement in reforestation
success is expected from recognizing and
correcting conspicuous problems.

Improved communications between nursery
managers, field foresters, and researchers,
eventually developing feedback linkages
between these groups based on common goals.

Improved cultural and handling methods in
the nursery by utilizing the database to aid
decisions on when to perform certain practi-
ces, and to document the effects on seedling
quality and performance.

Long-term (5 years and longer)

Significantly increased and more consistent
tree survival and growth after outplanting,
with fewer failures and replants, and lower
reforestation costs. We should see increased
efficiency through the entire reforestation
process .

Development of specific cultural regimes to
match seedlots and seedling characteristics
to individual sites, thus utilizing the full
potential of each site.

Improved nursery practices and knowledge of
the relations between stock quality, site
conditions, and field performance will
improve our ability to predict tree survival
and growth on a variety of sites and optimize
the cost of stock production.

Development of a flexible quality control
program for individual nurseries that can be
continually refined. Seedling production
will gradually shift from an art to a science,
enabling nursery managers to manipulate
numerous variables and consistently grow
seedlings to target specifications.

is monitoring both loblolly and longleaf pines.
Ten nurseries made their initial sowings in 1986,
and one nursery began this year.

The same seedlots of each species will be
sown for 3 consecutive years so that they will be
grown under a variety of weather conditions.
Standard cultural practices will be used in the
100 feet of seedbed that will be sown for each
seedlot and year. All the sowings will be
clustered as close together as possible so that
they are in similar soil and subject to similar
weather conditions.

ENVIRONMENTAL MEASUREMENTS

Electronic recording weather stations are the
heart of the environmental monitoring phase of RIP.
One station is located on a permanent site at each
nursery to collect baseline weather data. A second
station is located near the test seedbeds so that
sensors can monitor the weather and soil condi-
tions to which the seedlings are actually exposed.
Conditions measured are: air temperature at 1.5m
above ground and at the seedling canopy level
(20 cm), relative humidity, precipitation and
irrigation, wind speed and direction, incoming
radiant energy and photosynthetically active
radiation, soil surface temperature, and soil
temperature and moisture in the seedling rooting
zone. The recorder scans the sensors every 5
minutes and records the hourly maximum, minimum,
and average temperatures; average humidity, radi-
ation, and wind direction; average and maximum
wind speed; and total precipitation or irrigation.

One-time measurements of soil physical
characteristics were made in the test beds, and
periodic measurements will be made of soil fer-
tility, pathogen levels, and quality of irrigation
and runoff water.

Environmental conditions that the seedlings
are subjected to during lifting, processing,
shipping, and planting will be carefully monitored.
This will include factors such as root exposure
time; temperatures during grading, storage, and
shipping; and number of times the seedlings are
handled. Temperatures during storage and shipping
will be measured by another recording device, a
Datapod^, that will be placed inside packing bags
to record temperature hourly until the seedlings
are removed from the bags for planting.

These environmental and history data will
be used in graphics, in correlations with seed-
ling growth in the nursery, and in interpreta-
tions of observed responses to culture.

ESTABLISHMENT OF NURSERY PLOTS

Each nursery is monitoring two different
seedlots of at least one of the major species
that it produces; five western nurseries are
monitoring ponderosa pine, four western nurseries
are monitoring Douglas-fir, one northern nursery
is monitoring red pine, and one southern nursery

^The use of trade or firm names in this
publication is for reader information and does not
imply endorsement by the U.S. Department of Agri-
culture of any product or service.

122

CULTURAL PRACTICES

ESTABLISHMENT OF FOREST PLOTS

All cultural activities performed on the
test seedlots will be documented by date and
specific treatment. Any errors and unusual
occurrences will be noted. Cultural practices
include seed stratification, sowing, mulching,
thinning, weeding, fertilization, irrigation,
pesticide application, shoot and root pruning,
and wrenching. No experimental treatments will
be applied to the monitored seedbeds, but if any
practice is changed nursery-wide during the
program, the modified practice will also be
instituted in the RIP seedbeds. This information
will be used primarily for interpreting results
rather than for making specific correlations
with growth and performance.

SEEDLING MEASUREMENTS

Despite all the high-tech gadgetry, seed-
lings are the main focus of the program. We
will examine them outside and in, i.e. morpho-
logically and physiologically, and correlate
their development, growth, and condition with
(1) nursery environment and culture, and (2)
field performance.

The payoff is, of course, field performance
of the seedlings. It makes no sense to grow high
quality seedlings if they are going to fizzle after
outplanting, or disappear into the unknown.
Therefore, we have asked various Forest Service
Ranger Districts to establish and monitor test
plantations. Planting stock from each nursery
will be outplanted on two forest sites; each will
have an electronic weather station identical to
those used at the nursery. The sites will be
partially planted in each of 3 consecutive years.
Depending on the compatibility of the monitored
seedlots with the seed zone of each forest site,
some test plantations will be planted with both
seedlots and others will have only one. Only 200
seedlings per seedlot will be planted and tracked
per site, so it will not be a heavy workload.
Site preparation will be the biggest problem on
many sites because the program requires that
approximately one-third of each site be planted
in each of 3 consecutive years, but with site
conditions as similar as possible. We will work
individually with each National Forest to develop
a planting plan that is operationally feasible,
statistically valid, and consistent with RIP plans
and objectives.

Monitoring will begin with establishment of
history plots at time of sowing to determine
germination rates and plantable seedlings as a
percent of seeds sown. Random samples of seed-
lings in the seedbeds will be repeatedly measured
to determine height and diameter growth, bud
activity, and foliage color; and separate samples
will be destructively measured to obtain root
growth. We will monitor plant moisture stress
during dormancy induction and mineral nutrient
status in the fall when the seedlings have
stopped growing.

Several measurements and tests will be done
when seedlings are lifted: morphological (exter-
nal) characteristics will be measured — height,
stem diameter, bud length, dry weight, and
foliage color; and physiological (internal)
conditions will be assessed by several tests —
mineral nutrient status, carbohydrate reserves,
root growth potential, cold hardiness, and
stress resistance.

Carbohydrate and mineral nutrient analyses
require sophisticated equipment and will be done
by private or university laboratories. The root
growth potential, cold hardiness, and stress
tests, however, will be done at the nurseries.
This will be more economical, and the seedlings
will not be subjected to storage and shipping
that might alter their physiology. The main
reason for doing the tests on site, however, is
to give nursery personnel greater familiarity
with the specialized measurements and tests of
planting stock quality.

As with the nursery phase, environmental
conditions, handling, seedling characteristics,
and seedling performance on the field plots will
be recorded for later analyses and correlations.
We are working with the National Forests this
year to make sure preparations are made for
installing forest plots during the 1988 planting
season.

DATA HANDLING AND ANALYSIS

Data collection and analysis are critical
parts of RIP. The general plan for data flow is
as follows:

National Steering Committee

Computer Center
(Archive)

123

Each nursery was provided with a micro-
computer, electronic weather stations and data
reader, datapods and reader, a portable data
collector, and software to receive the trans-
mitted data, automatically summarize it, and
archive it.

Weather data are stored in a removable
memory pack that holds 32,000 bits of information
(64 K packs are now available) . The packs are
changed once a month. A full pack is plugged
into a special reader that transmits the data
to a microcomputer where a communications pro-
gram captures it and stores it as an ASCII file.
The pack is then erased and reused. The same
scheme is used to retrieve package temperature
data stored in the Datapods. The scheme designed
for the portable data collector to collect seed-
ling data and transmit it to the computer for
processing is covered in more detail in a separ-
ate paper (Rietveld and Ryker 1988) .

ASCII files containing the data are impor-
ted into Preformatted spreadsheets where stand-
ardized data summaries and graphs are automa-
tically generated through the use of macros.
Graphs of weather data show monthly summaries
of: incoming radiant energy, photosynthetically
active radiation, precipitation, percent relative
humidity, air temperature at 1.5 m, air tempera-
ture at 20 cm, wind speed, wind direction, soil
surface temperature, soil temperature at 15 cm,
and soil moisture at 15 cm. Graphs of seedling
data are generated showing: seed germination,
height growth, caliper growth, root growth, and
bud activity, all in relation to time, air tem-
peratures, soil temperatures, soil moisture, and
solar radiation. Parameters such as growing
degree days, chilling hours, and potential
evapotranspiration are also calculated. Raw
and summarized weather and seedling data from
the nurseries and forest sites are archived at
the nursery, and summarized data are archived at
the National Computer Center at Fort Collins,
CO, for safekeeping and sharing with approved
interested parties.

Nursery

Weather
History
Culture

Nursery

Seedling growth
vs Seedling morphology
Seedling physiology

Field

Seedling morphology Seedling cond. on arrival

Seedling physiology vs Seedling surv. and growth
Processing & handling

Field

Site weather
Site history
Pest problems

Field

Seedling surv. and growth

Scientific analysis is expected to take the
following progression:

Observations

1. Evaluate field performance — if a seedlot
does poorly at one site and not at the other
site, look at site data; if a seedlot per-
forms poorly on both sites, look at both
site and seedling quality data.

2. Evaluate repeatedly measured variables (seed-
ling height, caliper, root growth, foliage
color, bud activity, plant moisture stress,
root growth potential, and carbohydrate
reserves) — the only thing that can be done
early in the program is to flag anything
that looks suspect, since we don't know what
constitutes a normal level for the variables
at each nursery.

3. Contrast variables — note differences in
selected variables between seedlots, sites,
and nurseries (for the same species) . Graph
selected variables for all nurseries growing
the same species (ponderosa pine or Douglas-
fir) to become familiar with basic nursery
and seedlot differences.

INTERPRETATION OF DATA

Nursery managers can manipulate the data
and generate other summaries and graphs as they
wish. Such information will be useful in plan-
ning and evaluating day-to-day nursery operations
and making decisions, as well as building a
strong database for continuing quality control.

The data will also be evaluated by RIP's
scientific analysis team. Because RIP is not a
controlled research experiment, the opportuni-
ties to apply statistical analyses will be
limited. Initially, the team will be restricted
to making inferences based only on observations;
after data are collected for three crops of
planting stock (fall 1990) , it will be possible
to apply some limited statistical analyses. The
general types of comparisons that will be made
are as follows:

4. Evaluate models and indices — evaluate the
usefulness of various models to relate weather
variables to seedling growth and phenology
(e.g. degree hours with seedling growth in
the nursery, chilling units with cold hardi-
ness, etc); and evaluate the ability of
existing stock quality indices to predict
seedling quality and performance.

5. Evaluate unusual events — evaluate the
effects of any disasters or any unusual
weather events, contrasting nursery practices
and field operations.

Statistical Analyses

1. Correlations — by fall 1990, we will have
first-season performance data on three crops
of planting stock on each of two forest sites,
giving a sample size of six for each seedlot.
Correlation analysis of planting stock quality

124

variables (seedling height, caliper, dry
weight, root growth potential, carbohydrate
reserves, etc.) with performance variables
(survival, height growth, caliper growth,
etc.) will be barely possible becaue of the
small sample size.

2. Regression analyses — simple linear re-
gression will be possible after we have data
for three crops of stock. However, the real
power of regression analysis cannot be
realized until a sufficient range of data
points is available, which will come with
additional years of monitoring. To some
extent, datasets can be expanded by includ-
ing data from more than one seedlot and
nursery (for the same species) , but only

if they satisfy certain tests for common
regressions .

3. Develop standards and indices — with
sufficient data, application of single

and multiple regression analyses will allow
inferences of cause and effect relations in
the nursery, between the nursery and the
field, and in the field. Consistently sig-
nificant relations may be used to develop
indices that can be conveniently applied to
predict response. In the process, we will
evaluate, modify, and adapt existing
indices and models for individual nurseries.

SUMMARY

The USDA Forest Service has undertaken an
ambitious program to accelerate the transition
of nursery management and reforestation from an
art into a science. The goals of the Refores-
tation Improvement Program are to (1) supply

each nursery with state-of-the-art equipment and
methods for recording weather, cultural, and
seedling variables; (2) develop a monitoring
system that links the nursery with the field and
provides a system for feedback; and (3) develop
a computerized database for each nursery that is
easily accessed, is interactive with nursery
management, and will eventually guide refinements
in nursery culture and field operations. The rea!
value of the database will grow in direct propor-
tion with the quality and completeness of the
data put in, and with time. There will be only
a limited ability to extract information from the
databases during the first few years; mostly we
will benefit professionally by increasing the
depth of our documentation and awareness. The
real payoff comes with the accumulation of data
over years. Eventually, with the assistance of
research, we will develop culture/quality/perfor-
mance relations for individual nurseries,
establish appropriate stock standards, and
greatly improve our ability to predict seedling
performance on a variety of sites.

LITERATURE CITED

Jenkinson, James L. 1980. Improving plantation
establishment by optimizing growth capacity
and planting time of western yellow pines,
U.S. Dept. Agric, Forest Service, Pacific
Southwest Forest and Range Exp. Stn. ,
Berkeley, CA 94701, Research Paper PSW-154,
22 p.

Rietveld, W.J. and Russell A. Ryker. 1988.

Applications of portable data collectors
in nursery management and research.
Tree Planter's Notes (in press).

125

Government vs Private Nurseries: The Competition Issue^

Thomas D. Landis^

Abstract. --The issue of competition between government and
private forest tree seedling nurseries has been politically
sensitive in recent years. An analysis of both the different
types of nurseries and seedling markets provided an
information base. The question of competition in the forest
nursery business can be analyzed in terms of seedling price
and quality in the open and closed seedling markets.
Although some degree of competition between government and
private nurseries is inevitable, a number of positive
approaches are presented which can overcome or prevent
serious problems.

INTRODUCTION

Over the past decade there has been
increasing concern over the issue of
competition between government and private
forest tree seedling nurseries. Advocates of
nursery privatization have gone as far as
introducing legislation both on the federal and
state level to eliminate government-run
nurseries. A recent informal survey was
circulated to state forest nursery managers in
the west to determine the extent of the
government/private nursery competition
problem. Survey responses indicated that all
western nursery managers were concerned about
the nursery competition issue, and that there
was a serious problem in 2'^% of the states at
the present time.

Actually, the government /private nursery
controversy is not a new topic, but has
surfaced several times in the past as evidenced
by an editorial cartoon that appeared over ^15
years ago (Figure 1). This cartoon was
generated by the introduction of legislation
that proposed the abolishment of the California
State Tree Nursery at Davis. Apparently, the
newspaper editors considered closing the state
nursery a foolhardy proposition.

Responding to this widespread concern, the
organizational committee for the I987
Intermountain Forest Nursery Association

Paper presented at the Intermountain
Forest Nursery Association meeting, Oklahoma
City, Oklahoma. August 10-14, I987

Thomas Daniel Landis is Western Nursery
Specialist, USDA-Forest Service, Pacific
Northwest Region, Portland, Or.

meeting decided to explore the nursery
competition topic. Rather than have formal
presentations expressing divergent, and
sometimes polarized, points of view, an
informal format was designed that encouraged
communication and discussion. The facilitated
small-group discussions generated a

Barking Up The Wrong Tree

Figure l.--The government/private nursery

controversy as depicted in the Sacramento
Bee, April 4, 19^1 (courtesy of G.A.
Ahlstrom)

126

comprehensive list of ways in which all forest
seedling nurseries can work together to
resolve, and possible prevent, confrontation.
This article was written to serve as an
introduction to these small-group discussions.

The purpose of this article is to provide
perspective on the government/private nursery
controversy, which will hopefully lead to an
increased understanding of the issues involved
and some mutually acceptable solutions. Before
we can analyze the government/private nursery
issue, however, both the types of nurseries and
the types of markets in the forest tree
seedling business must be defined.

TYPES OF FOREST NURSERIES

Nurseries that grow woody plant seedlings
can be organized into four classes:

1 . Federal nurseries - these government
nurseries, such as those operated by the
USDA-Forest Service or USDI-Bureau of Indian
Affairs, were established to produce seedlings
for government forest lands. Most are
prohibited from directly selling seedlings to
other forest land holders or on the ornamental
seedling market.

2. State nurseries - nurseries operated by
state governments produce seedlings for a wider
range of markets, including state forest lands,
but also sell seedlings for conservation
purposes on private forest lands. They are
generally prohibited from selling seedlings for
ornamental purposes.

3. Industrial nurseries - some of the
larger forest industries have nurseries which
produce seedlings for their own lands but also
sell seedlings on the open market, including
ornamental sales.

4 . Private nurseries - these nurseries are
operated by private individuals or corporations
and sell seedlings for all purposes in any
market.

TYPES OF MARKETS FOR FOREST TREE SEEDLINGS

There are two types of markets in the
forest nursery business:

1. Open markets - seedlings can be
purchased without restriction from any
supplier. The open market consists of both
large and small landowners who purchase
seedlings from state, industrial, or private
nurseries for a variety of conservation
planting purposes.

2. Closed markets - customers are obliged

to purchase their seedlings from one supplier.
Ebcamples of closed markets can be found in both
the government and private sectors. Tree
seedlings for most federal forest lands are
traditionally purchased from an associated
government forest nursery. Some timber
companies have also developed nurseries to
produce seedlings for their own lands.

Another related, yet slightly different,
market for woody plant seedlings is the
ornamental seedling market which consists of
seedlings sold for landscaping rather than
conservation purposes.

DEFINING AND EXAMINING THE COMPETITION ISSUE

According to Webster's Dictionary,
competition is defined as "the effort of two or
more parties acting independently to secure the
business of a third party by offering the most
favorable terms". The question of competition,
therefore, hinges on the phrase "most favorable
terms" which, in the tree seedling nursery
business, breaks down into 2 components: price
and quality. These two factors can be analyzed
in both the open and closed seedling markets:

The Pricing Issue in the Open Market

Most private and forest industry nurseries
set their seedling prices based on demand in
the open seedling market. There are basically
two pricing structures in the open market:
"spot market" and "contract". Spot market
prices are established near the end of the crop
rotation and are dependent on the traditional
economic forces of supply and demand. Contract
seedling prices are set at the time of contract
award, before the seed is even sown, and are
controlled by the terms of the specific
contract. Most smaller landowners purchase
their seedlings at the spot market price,
whereas larger landowners and government
nursery organizations normally purchase open
market seedlings by contract.

Many state government nurseries have
traditionally kept their seedling prices low to
stimulate tree planting for conservation
purposes. However admirable this pricing
policy may be, it actually fuels competition
because it keeps seedling prices below the open
market value. Private nursery managers have a
valid case when they contend that these
artificially-low priced seedlings may lure
potential customers away from their nurseries.
One solution to the price issue is to set state
nursery prices higher than private sources such
as is being done by the California Division of
Forestry. Using the dictionary definition,
competition between state government and
private nurseries would be eliminated under
this pricing policy.

127

The Quality Issue in the Open Market

Although there has been much discussion
and interest about seedling quality, this
attribute remains an elusive property. Much
research has been done on this subject, but
there is still no standard definition or
procedure for determining seedling quality.

Seedling quality is also variable from
region to region. Because of vast differences
in outplanting site conditions and in the
genetic constitution of a seedling, an
acceptable seedling from one geographical area
may not survive in another. This is often due
to the fact that seedlings adapted to lower
elevations and milder climates are less
cold-hardy than local species and can be
damaged, or even killed, when planted in areas
with harsher winters.

The use of source-identif ied ,
locally-adapted seedlings is absolutely
essential in conservation plantings to insure
that the seedlings will survive and grow after
outplanting. The use of source-identified seed
is well supported in the scientific literature
although it is conveniently overlooked in some
unprofessional nursery transactions. The
question of whether locally-grown seedlings are
better adapted to local planting sites is not
as clear, but this practice has been
traditionally emphasized by foresters in
climatically-diverse areas like the
Intermountain West. This "source-identified,
locally-adapted" concept is critical in the
forest nursery industry because the general
public might be tempted to buy tree seedlings
based on general appearance and price rather
than quality.

The need for source-identified,
locally-adapted stock is not as critical to
many ornamental tree seedling growers t ocause
they deal with "cultivars" that are selected
for foliage color or some other ornamental
trait. Because they are planted in landscape
situations where environmental stresses are
minimal, cultivars can be produced by many
different nurseries and are normally shipped
over wide geographical areas.

Seedling quality is also a function of
what happens to a seedling after it is
harvested from the nursery. Many nurseries can
grow reasonably healthy seedlings, but are not
equipped to properly handle seedlings through
the storage and distribution phase. Most
larger forest nurseries in the west, both
government and private, have well-designed
seedling storage facilities and handling
procedures. In some states with smaller
seedling programs, however, government
nurseries are often the only ones who have
properly designed seedling storage and delivery
systems - facilities like refrigerated storage
and distribution vehicles that take seedlings
out to the customer (e.g. "Trees on Wheels"

programs run by several western state forestry
organizations) .

Seedling Price and Quality in Closed Markets

Many nurseries that produce seedlings for
their own use generally set prices based on
production costs, rather than open market
value. The price of federal government nursery
seedlings is annually computed based on the
cost of production, and therefore seedling
prices reflect both variable costs like
fertilizer and fixed costs such as machinery
depreciation. In the past, because federal
nurseries sold seedlings to the closed
government market, the question of price
competition with private nurseries was somewhat
irrelevant. Now that private nurseries are
producing contract seedlings for federal forest
lands, however, the price issue becomes more
meaningful and competition is possible.

One of the most important issues
concerning the future of government seedling
contracts with private nurseries revolves
around the issue of seedling quality: the
proven ability of private nurseries to supply
quality seedlings on a sustained basis.

1 . Proven ability - Many private nurseries
have shown that they have the ability to
produce quality forest tree seedlings, although
a few nurseries with first-time contracts have
not performed satisfactorily. Established
nurseries that have demonstrated a good
seedling production record, however, can expect
to continue to receive government contracts.

2. Quality seedlings - Although some
private nurseries have shown that they can
produce good quality seedlings, government
foresters have had some serious problems with
private nursery contracts. Many of these
problems have centered around contract seedling
specifications: one of the relevant questions
here is whether anyone can really write
contract specifications that define something
as complex and controversial as a "quality
seedling" .

There is also a tendency among many
government contracting officers to think of
seedlings as inanimate production units -
"widgets". These non-biologists mistakenly
think that quality tree seedlings are like any
other contract item and can be routinely
produced by anyone with the proper equipment.
On the contrary, the ability to consistently
produce a high-quality forest tree seedling
crop requires technical expertise and cultural
ability seasoned by experience, in addition to
a suitable nursery facility.

The quality issue is not restricted to
government contracts with private nurseries.
Government nurseries also have problems with
seedling quality from time to time, yet
government foresters are often discouraged from
purchasing seedlings from other sources.

128

3. Sustained basis - This issue is a
"catch-22" and must eventually be resolved over
time. Unfortunately, many government agencies
only issue single-year seedling growing
contracts and award them to the lowest bidder.
Individual private nurseries have no way to be
certain that they will have part of the
government seedling market from year to year.
Because of this ephemeral demand, many private
nurseries have no way to prove that they can
fulfill government seedling needs on a
sustained basis.

The federal government has been purchasing
more seedlings from private nurseries in recent
years. As an example of this changing policy.
Region 6 of the USDA-Forest Service (Oregon and
Washington) has gradually increased its
contracting requests for privately-produced
tree seedlings. The number of private
nurseries with Region 6 seedling production
contracts has risen from 6 in 1984 to 10 in
1987, and the percentage of the total seedling
orders filled by private nursery contracts has
increased from 8 to lk% over the same time
period .

CONCLUSION: SOLUTION THROUGH COOPERATION

The solution to the problem of
government/private nursery competition must
eventually be resolved through the cooperative
efforts of all the parties involved. As is
true in animal ecology, competition between two
different organisms rarely leads to direct
conflict, but rather to some
socially-acceptable modification in the
behaviour of each individual.

True to this ecological adage, a spirit of
cooperation was evident in the small-group
discussions during the government/private
nursery session at this meeting. The opening
statements of many participants reflected
divergent viewpoints but, as they heard the
positions of other group members, traditional
barriers began to vanish. Two of the most
significant observations to come out of these
discussions were:

1. The government/private nursery
competition issue is much more complex than
most people originally thought. As is often
the case, there are no simple solutions and
increased communication between all concerned

parties is necessary to increase mutual
understanding.

2. The situation varies considerably from
one region of the country to another. What is
true in the Pacific Northwest does not
necessarily apply to the Great Plains or the
South. Because of this regional variation, the
problem should be treated on a local , rather
than a national, basis.

As a product of these enlightening
discussions, each group developed a positive
list of ways in which all nursery managers can
cooperate and resolve potential conflicts in
the future (details of this exercise are
reported in Session Two of the following
article) . Some of the more noteworthy ideas
were:

1. Establish regional nursery advisory
boards composed of representatives from both
the public and private sector. The activities
of these advisory boards would include planning
and coordination, establishment of seedling
quality standards, and conflict prevention.

2. Stimulate better communication between
all types of nurseries to minimize potential
conflicts and take advantage of opportunities
to cooperate. This could include regular
visits to other nurseries, and participation in
local nursery associations.

3. Promote use of private nurseries for
government seedling procurement, not only for
excess needs, but as part of the annual
program .

k . Each government nursery should develop
a formal nursery policy that spells out their
operating guidelines and how they relate to
private sector nurseries with respect to
potentially harmful practices like seedling
marketing and surplus seedling sales.

The author would like to express his
appreciation to Steve Hee of Weyerhaeuser
Company, Jerry Ahlstrom of the California
Department of Forestry, and to Dick Miller and •
Paul Forward of the USDA-Forest Service for
providing valuable insight into this important
issue and taking the time to review the
manuscript .

129

Working Group Sessions on Communications and the
Government/Private Nursery issue^

Kurtis L. Atkinson^

Abstract. — Facilitated working group
sessions were held to develop lists of
actions to improve communication and
cooperation among nurseries in the Great
Plains, and reduce the conflict between
the government and private nursery
sectors. These actions may be used as a
starting point to improve working
relationships between all nurseries.

Session I: Communications

A working-group exercise was held
to identify areas in which forest nur-
series could cooperate, communicate and
share ideas. The attendees were divided
randomly into four groups, and led
through the process by a trained facili-
tator. It was structured as follows:

Purpose

Find ways to increase communica-
tion and cooperation between forest
nurseries .

Desired Outcome

A list of opportunities for
increased cooperation and communication
between forest nursery organizations.

Process

Nominal Group Technique

Results derived from working group
sessions at the 1987 Intermountain Forest
Nursery Assoc. meeting [Aug. 10-14, 1987,
in Okla. City, Okla. ] .

Kurtis L. Atkinson is Assistant
Director of the Forestry Division of the
Okla. State Dept. of Agriculture, Okla.
City, Okla.

Results

The results from the four groups
follow. No attempt was made to consol-
idate these lists. The asterisks {*)
denote items given a high priority by
each group and were the only ones pre-
sented to the entire assembly.

Conclusion

It is hoped these results will
stimulate interchange between nurseries,
and perhaps serve as the basis for a
formal method of exchanging and sharing
information. The participants themselves
must take the initiative to further
develop these ideas into a workable
method to take advantage of the
opportunities which are evident.

Group I

* 1. List of tree seed, seedlings and

surpluses

2. Political issues facing nursery
business

3. New cultural practices

* 4. Share information on pesticides

and new insects & diseases

* 5. Co-op seed collection

6. Lists of salvage or replacement
equipment

7. Tested modifications in nursery
equipment

8. "Bugs & Cruds" problems and
solutions

9. Interacting with locally operated
nurser ies

10. Quick response on first time
problems

130

11. Use of by-products, recycling,
etc .

* 12. Improvements in safety

13. Bareroot precision sowing

14. Facilities that may be available
( contract/otherwise )

15. Species list

* 16. Nursery practices which enhance

outplanting survival

17. Human resources available for
consultation

18. Alternative labor sources
/employment opportunities

19. New insect & disease information

20. Development of national grading
standard

21. Seedling testing

22. Packing containers (type/cost)

23. Germinating problem species

24. Effective control of weeds

25. Improving customer relations

26. Odd species seed availability

* 27. Improved seed and seedling

storage

28. Good tiers (taers)

29. Bareroot vs. containers

30. Re-cycling to save costs; tubes,
boxes, etc.

31. List of suppliers, costs, bulk
ordering

32. Cooperative studies of cultural
practices

33. Results of seedbed densities

34. Sample contracts

* 35. List of current nursery studies

36. Grading & handling of bareroot
stock

37. Outplantings , contracts,
contractors, equipment

38. Bookkeeping practices

39. Research & observation of new
methodology

40. University resources (testing
pers.on power)

* 41. Innovative ways for seed

stratification
42. Accurate forecasting needs &
wants (market data)

Group II

* 1. Surplus/shortages of seedlings 5.

see<3

2. Quarterly recaps of productivity
and activities; a procedure for
dissemination

* 3. Educational program, i.e.,

training of staff, foremen, &
nursery personnel (management,
computers , etc . )

* 4. Seed collection, seed source

i.d., purchasing seed,
cooperation

5. Pooling of resources to promote
more intensive tree improvement
program between states

6. Incentives to increase
productiveness of seasonal labor

7. Consolidated purchasing of
materials and services

8. Interagency, state and regional
cooperation on I&E

* 9. Mechanical

innovations/developments

10. Sharing of equipment and supplies
in the event of breakdowns

11. Cooperative growing of seedlings

12. Personnel needs

13. Better feedback on plant material
success from the field

* 14. Information system that is

applicable to nursery management
and administration (principally
PC software)

15. Exchanging expertise in
specialized area

16. Equipment specification and
performance

17. Vendor listing by categories and
region

18. Join together to market products

19. Provide cooperative R&D on
problems and opportunities that
are common to nurseries

* 20. Information exchange of specific

cultural situations and problem
solving, including: pesticides,
pests, nutrients, soil/pesticide
interactions, innovations, seed
handling, collection, processing,
etc .

Group III

* 1. Day to day cultural and

operational tips

2. Record keeping

3. Harvesting techniques

* 4. Who's doing what (research, etc.,

names of contacts)

* 5. Listing of nurseries, species,

capacities, addresses, phone
numbers, etc.

* 6. Equipment technology & shared

equipment performance information

* 7. New laws relating to chemical

use, personnel management,
environmental constraints (in
understandable form - do's &
don ' ts )

* 8. Promotional techniques &

mater ials

9. R.I. P. information sharing

* 10. What's and How's in connection

with herbicide use

* 11. Inventory: surpluses, shortages &

pr ices

12. Surplus supplies inventory

13. Relate seedling quality to field
performance

* 14. Problem alert system

15. Job openings

16. Seed availability - price

17. Techniques of inventory control,
sales, and delivery management

131

* 18. Software needs & availability

19. Methods of packing

20. Cost reduction techniques

21. Evaluation of seed sources for
different products

Group IV

1. Success/failure in weed
management, herbicides, why?

2. Insect alerts, aphids/hoppers

* 3. What expertise do others have in

specific areas?

* 4. Software that others use such as

storage & retrieval of cultural
and production information

5. Training opportunities

6. Sharing, coordinating,
interpreting data

7. Telecommunications network

* 8. How inventories? Accuracy rates,

costs, procedures?
9. Calibrating mechanical seed
sowers, what accuracy
experienced?
10. Combined inventories of spare
parts

* 11. What supplies in common and where

acquired (boxes, chemicals, etc.)
possible coordination of
purchasing .

12. Surplus seed and seedlings

13. Surplus equipment

14. Available services (tissue
analysis, diagnosis, etc.)

15. Seed sources (especially
hardwoods )

16. Comparing germination data

17. Coordinating equipment
development

18. Coordinating job opportunities

19. Bulletin board service with
telecommunications

20. Seedling packing containers and
medium

* 21. Success or failure of plantations

22. What policies or guidelines do
others use? (size of seedlings,
complaints, many more)

* 23. Success/failure - pest

management, fungicides,
fumigants, insecticides, why?
24. New materials available for pest
control

* 25. What criteria others use to

determine seedling quality?
Equipment used? Which best to
predict field survival?
26. Comparing clean seed yields

* 27. Ideas about formal research and

informal trials underway at other
nurseries, results.

* 28. Availability and use of climatic

data to plan planting schedules
and make yield predictions.

* 29. Successes/failures in soils

management (pH, fertilization,
etc. )

30. Storage temperatures by species.

* 31. What species are others growing?

What cultural practices?

* 32. Planting methods, methods of

reforestation, equipment, etc.

33. Invite a friend to lunch and
share information.

34. Tonight is ladies night in the
bar .

Session II:
Government vs Private Nurseries

A second working-group exercise
was held to address the government
/private nursery issue. The attendees
were divided randomly into three groups,
each with a trained facilitator and
recorder who coordinated the process. It
was structured as follows:

Issue

Private sector concerns about
competition from publicly operated
nurseries .

Purpose

1. Stimulate participants'
minds about things they or their
organization can do to help reduce
concerns about this issue.

2. Document the suggestions of
this group of experts, close to the
issue, for use by various organizations
who may be studying the issue.

Process

Facilitated Discussion

Results

The results from the three groups
follow. No attempt was made to priori-
tize the ideas with-in the groups, nor to
consolidate the statements for the con-
ference as a whole.

Conclusions

The result of this session will
be provided to the National Association
of State Foresters to use during their
consideration of this issue. The parti-
cipants should also take the initiative
to further develop these ideas into a
workable, cooperative and mutually
agreeable plan of action.

132

GROUP 1

1. Artificially set seedling prices
from government nurseries higher
than private sector, on state by
state basis.

2. States develop a policy statement
related to public nursery
activities, with private sector
participation.

3. Contract with private nurseries
to produce stock for use on
public lands.

4. Establish a nursery advisory
board, with representation from
all sectors.

5. Assure selected (certified) seed
sources are available to all
growers .

6. Public education about the need
for quality seed sources,
species, quality of planting
stock, etc.

7. Regional coordination of nursery
policies, etc.

8. Assure private sector is included
as an option during public agency
technical assistance (CRP).

9. Establish basic standards of
stock quality, seed sources,
species selection.

10. Public and private sectors
should target market areas.

11. Nursery Board act in conflict
resolution .

12. Define, clarify and continue to
evaluate the need for public
nur ser ies .

13. Public nurseries become more
involved in private associations
(e.g., AAN, State Association,
etc. )

GROUP 2

1. Public nurseries should develop
marketing policies with input
from private and public sectors.

2. Develop joint
promotional/educational effort to
encourage tree planting.

3. Develop nursery advisory boards
by state/region involving all
sectors - public (state &
federal) and private.

4. Personal contact with private
nurseries for the purpose of
information exchange by field and
nursery personnel.

5. Sponsor a public nursery
inventory surplus list for
distribution to local private
nurseries for seedlings that are
available for sale.

6. Public nurseries should charge
their actual production costs
(including costs of land and
overhead ) .

7. Utilize private nurseries to
provide flexibility rather than
expand public nurseries (includes
contracting special needs,
trading stock, etc.)

8. Develop a positive medium for
information/technology transfer
promoting cooperative
partnerships .

9. State/Federal Forester rep,
should belong to State Nursery
Assoc .

GROUP 3

1. Increase communication among all
groups .

2. Share in each others planning
process .

3. Increase supply contracts to
private nurseries (state &
federal ) .

4. Moth ball marginal state or
federal nurseries.

5. When comparing quality and cost,
use the same criteria and
accounting procedures.

6. Establish regional advisory
boards to address needs and
impacts .

7. Moth ball or contract out low
demand species.

8. Limit the programs eligible for
discounted seedlings.

9. Sales from government nurseries
to private nurseries.

10. Study competition issues in other
industries. How do they resolve
problems?

11. All public nursery managers join
their state's nursery
association .

12. Have people involved in harvest
planning on advisory boards to
help predict the future.

13. Separate state and federal issues
when talking about alternatives.
Separate conflicts/address
separately .

14. Show and tell at public nurseries
for private nursery managers.

15. Examine decentralized seedling
procurement in the federal
system.

16. Make sure advisory board members
are knowledgable .

17. Make sure spokesmen from private
sector are expressing the
majority opinion.

18. Standard grading for seedlings.

19. Develop an action plan.

20. Implement.

133

Minutes of the Annual Business Meeting

The meeting was called to order by Tom Landis
at 8:30 A.M. on Friday, August l4.

Old business: The Proceedings of this
meeting will again be published as a General
Technical Report by the Rocky Mountain Forest
and Range Experiment Station, with funds
provided by State and Private Forestry,
USDA-Forest Service. The last date for papers
to be submitted for the Proceedings is October
1, 1987, and target date for publication is
January 1, 1988. Send papers to Bob Hamre at
the Research Station, or call Tom if you have
questions.

New business: The I988 Intermountain
Forest Nursery Association meeting will be held
in Vernon, B.C. on August 10-12, I988. This
will be a joint meeting of the Intermountain
Nursery Association, the Western Forest Nursery
Council, and The Forest Nursery Association of
British Columbia. Ralph Huber of the B.C.
Ministry of Forests is coordinating the meeting
plans and an informational mailing should be

distributed this fall. Ralph can be contacted
at 604-387-8942 for more information.

The 1989 Intermountain Forest Nursery
Association meeting will tentatively be
scheduled for either North or South Dakota.
More information will be forthcoming as plans
develop.

The Intermountain Forest Nursery Association is
27 years old! Marv Strachan, nursery manager
emeritus and organizer of the first meeting,
has volunteered to develop an archive for the
association. He will be attempting to gather a
complete set of past proceedings, and index
them for easy reference. The end product will
be a complete set of all Intermountain Forest
Nursery Association Proceedings with a subject
index. Tom Landis added that State and Private
Forestry supports this project and will attempt
to secure financing.

There was no further business, so the
meeting was adjourned at 9:00 A.M.

134

List of Attendees

Larry Abrahamson

State University of New York

College of Environmental Science & Forestry

Syracuse, New York 13210

(315) 470-6777

Arbab Amanullah

Forestry Dept. of Navajo Tribe

P. 0. Box 230

Fort Defiance, AZ 86504

(602) 729-5165

Dr. Steve Anderson, Extension Forester

Oil Ag Hall South

OSU Forestry Department

Stillwater, OK 74078-0491

(405) 624-5514

Mark Andrews

Oklahoma State University
Dept. of Plant Pathology
Stillwater, OK 74078-0491
(405) 624-5643

Kurt Atkinson
Dept. of Agriculture
Oklahoma Forestry Division
2800 N. Lincoln Blvd.
Oklahoma City, OK 73105-4298
(405) 521-3864

Rick Barham

International Paper Co.
Rt. 1, Box 314A
Bullard, TX 75757
(214) 825-6101

Jim Barnett
U.S. Forest Service
2500 Shreveport Highway
Pineville, LA 71360
(318) 473-7243

Phylis Bernarding
Industrial Services, Inc.
P. O. Box 10834
Brandenton, FL 33507
800-227-6728

Gary Bliss

State University of New York

College of Environmental Science & Forestry

Syracuse, NY 13205

(315) 469-3053

Bill Boeckman
Weyerhaeuser Company
HC 64, Box 101
Ft. Towson, OK 74735
(405) 873-2617

Tom Boggus

Texas Forest Service
Office of the Director
College Station, TX 77843
(409) 845-2641

Jerry Bratton

Great Plains Forestry Specialist
Rt. 4, Box 182-A
Chanute, KS 66720
(316) 431-3858

John Brissette
U.S. Forest Service
2500 Shreveport Hwy.
Pineville, LA 71360
(318) 473-7243

Karen Burr

U.S. Forest Service

Rocky Mtn. Forest & Range Exp. Station

240 W. Prospect

Fort Collins, CO 80524

(303) 493-2257

John Burwell

Dept. of Agriculture

Oklahoma Forestry Division

P. O. Box 10

Park Hill, OK 74451

(918) 456-6139

Kenneth Conway
Oklahoma State University
Dept. of Plant Pathology
Stillwater, OK 74078
(405) 624-5643

Mike Conway
HMS Soil Fumigation
7610 Hwy. 41 N
Palmetto, FL 33561
(813) 722-5587

Charles Cordell
Forest Pest Mgt., USDA
Box 2680, 200 Weaver Blvd.
Asheville, NC 28802
(704) 259-0643

Roger Davis, Director
Dept. of Agriculture
Oklahoma Forestry Division
2800 N. Lincoln Blvd.
Oklahoma City, OK 73105-4298
(405) 521-3864

L. D. Delaney, Jr.

Louisiana Forest Seed Co., Inc.

RR 2, Box 123

Lecompte, LA 71346

(318) 443-5026

Gary Dinkel

U.S. Forest Service

Bessey Nursery

P. O. Box 38

Halsey, NE 69142

(308) 533-2257

135

R. Daniel Dolata
USDA-FS, Boise N.F.
Lucky Peak Nursery
HC 33, Box 1085
Boise, ID 83706
(208) 343-1977

Rob Doye

Dept. of Agriculture
Oklahoma Forestry Division
2800 N. Lincoln Blvd.
Oklahoma City, OK 73105-4298
(405) 521-3864

A. C. Dromgoole
Ridgeway Wood Products
RR 1, Box 105A
Rocky, OK 73661
(405) 946-0512

Dr. Fernando Erazo
Aglukon, Inc.
P. O. Box 17088
Newark, NJ 07194
(914) 268-2122

Dane Erickson
Lincoln-Oakes Nurseries
Box 1601

Bismarck, ND 58501
(701) 223-8575

Dr. Ted Filer, Jr.
USDA Forest Service
Southern Hardwoods Lab.
P. 0. Box 227
Stoneville, MS 38776
(601) 686-7218

George Finger
Weyerhaeuser Company
Tacoma, WA 98477
(206) 924-5204

Clark Fleege
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 4 4
Washington, OK 73093
(405) 288-2385

Paul Forward

USDA Forest Service

P. O. Box 96090, Rm. 1201 RPE

Washington, DC 20090-6090

(703) 235-1637

Robert Gardner
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

Hugh Gerhardt
Old Mill Company
Savage Industrial Center
Savage, MD 20763
(301) 725-8181

Andrea Haley
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

Stephen Hallgren
Oklahoma State University
Dept. of Forestry
16 Agriculture Hall
Stillwater, OK 74078-0491
(405) 624-6805

Bob Harrel

Dept. of Agriculture
Oklahoma Forestry Division
2000 18th Street
Woodward, OK 73801
(405) 254-3213

Keith Harris

Oklahoma State University
Forestry Department
016 Agriculture Hall South
Stillwater, OK 74078-0491
(405) 624-5780

Beat Hauenstein
Bartschi of America, Inc.
16600 Robbins Rd . , Lot 512
Grand Haven, MI 49417
(616) 842-4470

Jim Heater

Summit/Silver Mt . Christmas Trees
4672 Drift Creek Rd.
Sublimity, OR 97385
(503) 769-7127

Stephen Hee
Weyerhaeuser Company
7935 Hwy. 12 SW
Rochester, WA 98531
(206) 273-5527

Floyd Hickam

Arkansas Forestry Commission
Rt. 1, Box 515C
North Little Rock, AR 72117
(501) 945-3345

Diane M. Hildebrand
U.S. Forest Service
Rocky Mtn. Region
11177 W. 8th Ave.
Lakewood, CO 80225
(303) 236-9542

Gary Hileman
U.S. Forest Service
Lucky Peak Nursery
HC 33, Box 1085
Boise, ID 83706
(208) 343-1977

136

Dr. Gordon Howe
PFRA Tree Nursery
Canada Agriculture
Indian Head
Sask. CANADA SOG 2K0
(306) 695-2284

Ralph Ruber

Ministry of Forests and Lands
Silviculture Branch
1450 Government Street
Victoria, BC V8W 3E7
(604) 387-8942

William Isaacs
South Pine, Inc.
P. O. Box 7404
Birmingham, AL 35253
(205) 879-1099

LaVar Jensen

Moses Lake Conservation Nursery

Rt. 3, Box 415

Moses Lake, WA 98837

(509) 765-4879

Robert Karrfalt
USDA-Forest Service
National Tree Seed Lab.
Rt. 1, Box 182B
Dry Branch, GA 31020
(812) 744-3312

Glenn Kranzler
Oklahoma State University
Agricultural Engineering
Stillwater, OK 74078-0491

(405) 624-5426

Tom Landis
USDA-Forest Service
Box 3623

Portland, OR 97208
(503) 221-2727

Joan Landrum

Texas Forest Service

P. O. Box 617

Alto, TX 75925-0617

(409) 858-4202

Clarence Lemons
Hendrix and Dail
P. O. Box 589
Oxford, NC 27565
(919) 693-4131

Bill Loucks

Kansas State & Extension Forestry
2610 Claflin Rd.
Manhattan, KS 66502
(913) 539-6092

Ben Lowman
U.S. Forest Service
Building 1, Ft. Missoula
Missoula, MT 59801

(406) 329-3958

Bill McCullers
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

Patrick A. McDowell
Dept. of Agriculture
Oklahoma Forestry Division
2800 N. Lincoln Blvd.
Oklahoma City, OK 73105-4298
(405) 521-3864

Blaine Martian

Bix Sioux Nursery

S.D. Division of Forestry

RR 2, Box 88

Watertown, SC 57201

(605) 886-6806

Dr. John Mexal
New Mexico State University
Dept. of Agronomy & Horticulture
Box 30003

Las Cruces, NM 88003
(505) 646-3335

Levoy Mizell

Buckeye Cellulose Corp.

Rt. 3, Box 260

Perry, FL 32347

(904) 584-0213

Randy Moench

Colorado State Forest Service
C.S.U. Foothills Campus
Fort Collins, CO 80523
(303) 491-8429

Greg Morgenson
Lincoln-Oakes Nurseries
Box 1601

Bismarck, ND 58501

(701) 223-8575

Patrick Murphy

Nevada Division of Forestry

201 S. Fall St.

Carson City, NV 89710

(702) 885-4243

Tom Murray

Dept. of Agriculture

Oklahoma Forestry Division

P.O. Box 1919

Burns Flat, OK. 73624

(405) 562-4885

Al Myatt

Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

Steven Omi

USDA Forest Service

Bend Pine Nursery

63095 Deschutes Market Rd.

Bend, OR 97701

(503) 388-5640

137

Bob Oswald

Trees Unlimited

9595 Nelson Rd., Box D

Longraont, CO 80501

(303) 776-4034

Alex Otey

PC Information Systems
P. O. Box 742454
Dallas, TX 75374
(214) 931-8378

Jeffrey Owen

USDA Forest Pest Mgt.

Box 2680, 200 Weaver Bldg.

Asheville, NC 28802

(704) 259-0643

Kenneth Quick
University of Idaho
College of Forestry
Moscow, ID 83843
(208) 885-6923

Nita Rauch
Bessey Nursery
P. 0. Box 3 8
Halsey, NE 69142
(308) 533-2257

Dr. W. J. Rietveld

U.S. Forest Service

North Central Forest Exp. Station

Rhinelander, WI 54501

(715) 362-7474

Frank Rothe
Colo-Hydro, Inc.
5555 Ute Hwy .
Longmont, CO 80501
(303) 449-5990

James Riley
P. 0. Box 2652
Edmond, OK 73083
(405) 348-3441

Tom Smith

Dept. of Agriculture
Oklahoma Forestry Division
Box 40

Broken Bow, OK 74728
(405) 584-3351

John South

PC Information Systems
6909 Custer Rd. Suite 708
Piano, TX 75023
(214) 964-2670

Marvin Strachan

Colorado State Forest Service

Foothills Campus

Ft. Collins, CO 80521

(303) 491-8429

Randy Thorpe

Division of State Lands & Forestry
Lone Peak State Seedling Nursery
14650 Prison Road
Draper, UT 84020
(801) 571-0900

Leaford Windle
U.S. Forest Service
3615 Los Picaros Rd., SE
Albuquerque, NM 87105
(505) 873-0750

Bill West

Loveland Industries, Inc.
3213 Sweetwater Dr.
Boise, ID 83705
(208) 386-9415

Dr. Carl Whitcomb
Rt. 5, Box 174
Stillwater, OK 74074
(405) 377-3539

Dennis Young
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

"OTHER ASSISTANCE"

Darlene Bolser
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

Jo Myatt

Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

Helen Newby
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

Steve Vaughn
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 44
Washington, OK 73093
(405) 288-2385

Charlotte Willis
Dept. of Agriculture
Oklahoma Forestry Division
Rt. 1, Box 4 4
Washington, OK 73093
(405) 288-2385

W U.S. GOVERNMENT PRINTING OFFICE:1988-574-1 10/85046

138

Rocky
Mountains

Great
Plains

U.S. Department of Agriculture
Forest Service

Rocky Mountain Forest and
Range Experiment Station

The Rocky Mountain Station is one of eight
regional experinnent stations, plus the Forest
Products Laboratory and the Washington Office
Staff, that make up the Forest Service research
organization.

RESEARCH FOCUS

Research programs at the Rocky Mountain
Station are coordinated with area universities and
with other institutions. Many studies are
conducted on a cooperative basis to accelerate
solutions to problems involving range, water,
wildlife and fish habitat, human and community
development, timber, recreation, protection, and
multiresource evaluation.

RESEARCH LOCATIONS

Research Work Units of the Rocky Mountain
Station are operated in cooperation with
universities in the following cities:

Albuquerque, New Mexico

Flagstaff, Arizona

Fort Collins, Colorado*

Laramie, Wyoming

Lincoln, Nebraska

Rapid City, South Dakota

Tempe, Arizona

•Station Headquarters: 240 W. Prospect St., Fort Collins, CO 80526

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Full text of "Meeting the challenge of the nineties : proceedings, Intermountain Forest Nursery Association, August 10-14, 1987, Oklahoma City, Oklahoma"

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