Full text of "The challenge of producing native plants for the intermountain area : proceedings, Intermountain Nurseryman's Association, 1983 conference, August 8-11, 1983, Las Vegas, Nevada"

See other formats

Historic, Archive Document

Do not assume content reflects current
scientific knowledge, policies, or practices.

United States
Department of
Agriculture

Forest Service

Intermountain
Forest and Range
Experiment Station
Ogden, UT 84401

General Technical
Report INT- 168

May 1984

8 A.

The Challenge of
Producing Native
Plants for the
Intermountain Area

Proceedings: Intermountain
Nurseryman's Association
1983 Conference
August 8-11, 1983
Las Vegas, Nevada

FOREWORD

Native plant materials are gaining status in
the nursery industry. There is a current
imbalance of supply and demand for the natives.
Plant scientists and a growing number of
nurseries are working to make more native
plants economically available.

This conference was designed to provide an
overview of procedures involved in the propa-
gation of native plant materials common to the
Intermountain area. This proceedings includes
the major papers delivered at the meeting.

-- Patrick M. Murphy

The use of trade, firm, or corporation names in this
publication is for the information and convenience of
the reader. Such use does not constitute an official
endorsement or approval by the U.S. Department of
Agriculture of any product or service to the exclusion
of others that may be suitable.

COVER PHOTO: The Leviathan Mine, an open-pit sulfur mine, illustrates
the challenges facing resource managers and researchers in revegetating
severely disturbed areas in the Intermountain area. The Leviathan is a major
source of pollution to the Lahontan watershed on the east side of the Sierra
Nevada. Recently, $3 million was appropriated through the California
Regional Water Quality organization to reclaim the site.

The Challenge of
Producing Native
Plants for the
Intermountain Area

Proceedings: Intermountain
Nurseryman's Association
1983 Conference
August 8-11, 1983
Las Vegas, Nevada

Compiled by:
Patrick M. Murphy
Assistant State Forester
Nevada Division of Forestry

Issued by:

Intermountain Forest and
Range Experiment Station
Forest Service

U.S. Department of Agriculture
507-25th Street
Ogden, UT 84401

CONTENTS

Page

Germination of Seeds of Wildland Plants
James A. Young, Jerry D. Bundy,
and Raymond A. Evans 1

Producing Bareroot Seedlings
of Native Shrubs

Nancy Shaw 6

Producing Native Plants as
Container Seedlings
Thomas D. Landis and

Edward J. Simonich 16

Use of Shrubs on Mine Spoils

Stephen B. Monsen 26

Toward Producing Disease-Free
Container-Grown Native Wildland Plants

David L. Nelson 32

Biology and Management of Botrytis Blight
Robert L. James 39

Page

Using a Pressure Chamber to Detect
Damage to Seedlings Accidentally
Frozen During Cold Storage

Douglas D. McCreary 58

Asexual vs. Sexual Propagation
of Quaking Aspen

Robert B. Campbell, Jr 61

Effects of Soil Amendments
on Aspen Seedling Production
James T. Fisher and

Gregory A. Fancher 66

Growth of Austrian Pine and Norway
Spruce Seedlings in Mini -Containers
Houchang Khatamian and

Fahed A. Al-Mana 69

Equipment for Revegetating Disturbed
Lands

Richard G. Hallman 74

Salt Tolerance of 10 Deciduous Shrub
and Tree Species

Richard W. Tinus 44

Containerized Seedling Production
for Forest Regeneration in the
Pacific Northwest

James M. Sedore 50

The Nursery Technology Cooperative:
A Coordinated Effort to Improve
Seedling Quality

Mary L. Duryea and

Steven K. Omi 53

Preliminary Trials on Upgrading
Platanus occidental i s with the Helmuth
Electrostatic Seed Separator
Robert P. Karrfalt and

Richard E. Helmuth 79

Survival , Growth, and Root Form
of Containerized Jeffrey Pines
Ten Years after Outplanting

J. D. Budy and E. L. Miller 82

Growing Containerized Tree Seedlings
in a Shadehouse

Thomas M. Smith 89

Attendance Roster

GERMINATION OF SEEDS OF WILDLAND PLANTS
James A. Young, Jerry D. Budy and Raymond A. Evans

ABSTRACT: Germination of wildland seeds is often
dependent on proper seed collection and storage.
Timing, seed collection, and the moisture content
of seeds in storage often influences germination.
A systematic approach to germination testing often
will pinpoint the type of dormancy of seeds in
wildland species and lead to germination enhance-
ment.

INTRODUCTION

Successful germination of seeds of plants collect-
ed from wildlands starts with proper collection of
the seeds. Both the timing of collection and the
handling of the freshly harvested seeds are impor-
tant .

TIMING THE COLLECTION OF WILDLAND SEEDS

Many wildland plant species have indeterminate
type inflorescences where flowering and maturity
are continuous for extended periods. This means
that seeds are ripe and falling from the inflo-
rescences at the same time blooming is still
occurring at other locations on the inflorescence.
It is difficult to avoid collecting immature seeds
in this situation. For determinate species that
mature at one time there is the danger of the
seeds suddenly being dehisced and lost unless they
are collected slightly before maturity.

Slightly immature seeds are not necessarily poor
germinators. The propagator has to determine the
influence of maturity on germination through trials.
To conduct meaningful trials, it is necessary to
label the seed collection with some detail of the
phenological stage of development, where the seed
lot was collected, and to maintain the identity
of the seed lot through germination trials.

Various maturity classes of seeds can be collected
by separating collections made on the same plant,
moving from early maturing south to north slope
communities, or by collecting at higher elevation
within the range of the species.

James A. Young and Raymond A. Evans are range
scientists for the USDA Agricultural Research
Service, Reno, Nev. Jerry D. Budy is Assistant
Professor of Forestry, University of Nevada, Reno,
Nev .

HANDLING FRESHLY HARVESTED SEEDS

A seed is a living organism in a resting stage,
but it is most important to remember that it is
alive! Freshly harvested seeds have too high a
moisture content for safe storage. The moisture
content of the seed must be allowed to reach equi-
librium with the atmosphere. In the Intermountai n
area this is usually simple because the relative
humidity of our air during the summer and fall is
usual ly qui te 1 ow.

For freshly harvested seeds to reach a moisture
equilibrium they must be stored in such a manner
to allow for free aeration. Uncoated paper or
mesh bags make good storage containers for initial
drying. Never use plastic bags for storage of
freshly harvested seeds!

Artificial drying, especially at high temperatures,
is usually not necessary, and often not desirable.
Screen freshly harvested material to remove high
moisture content trash. This will reduce drying
time .

Fleshy fruits require prompt treatment to remove
the fleshy material to avoid spoilage or mummifi-
cation of the fruits.

The seeds of species collected from marsh or wet-
land environments often require special handling.
The technique used depends on the species involved,
but often it is necessary to keep the seeds in a
cool, wet environment or actually stored in water
to avoid acquiring dormancy or loss of viability.

SEED CLEANING

Generally the sooner the seeds are cleaned and
placed in storage after they reach moisture equi-
librium, the less chance of predation from birds
or small mammals or contamination from insects.

Avoid rough handling of seeds during cleaning.
Remember the seed is alive and the embryo can be
very fragile. Never use a hammer mill in seed
processing unless you have first determined by
careful testing that seed viability is not being
adversely affected by the process.

Proper seed cleaning makes subsequent handling of
the seeds in the germination process much simpler.
Especially if the seed lot contains trash or empty
or obviously immature seeds, much time may be
wasted sorting the material to find germinable
seeds .

SEED STORAGE

To avoid problems with storage insects, start with
clean, insect-free storage conditions. Do not
introduce pests with the seeds to be stored.
Cool storage conditions lessen the chances of
insect problems.

The key to seed storage is maintaining proper
moisture conditions so that the seeds remain
alive, but ungermi nated . Remember that the amount
of water that the storage atmosphere will hold as
a vapor is directly related to temperature. If
you decrease the storage temperature of a sealed
container, moisture condensation will occur.

Storage in paper or mesh bags in a cool, dry
location is satisfactory for most seeds. Once the
seeds have reached moisture equilibrium, storage
in glass jars or plastic boxes is possible to
avoid insect or mold contamination. Some seeds
can be stored easily in small lots, but suffer
losses in viability when quantities of seeds are
stored together. Some seeds have inherently very
short storage lives and seed stocks of these spe-
cies must be removed annually.

GERMINATION TESTING

Two common determinations are made from seed tests:
viability and germi nabi 1 i ty. Viability simply
means the seed is alive. It does not indicate if
the seed will germinate. Viability tests may be
as simple as cutting a seed or fruit with a knife
blade to determine if an embryo is present. More
complex viability tests involve the use of the
chemical, tetrazolium. This chemical, after pro-
per sectioning and preparation of the seed, has
the property to accept hydrogen atoms from dehy-
drogentate enzymes during the respiration process
in viable seeds. Essentially, respiring or living
tissue in the seeds is evidenced by a red color
change.

The fact that the seeds or fruits contain living
tissue does not mean the embryo will germinate.
This is a common misinterpretation. For seeds of
the major crop species, standards have been deve-
loped that relate the tetrazolium reaction to
potential germination. These standards have not
been developed for the seeds of most wildland
species.

Germinabil i ty is a much more meaningful statistic
for individuals interested in propagating plants
from seeds. To obtain an estimate of germinabil ity,
the seeds must be subjected to a germination test.
The Association of Official Analysis (AOSA) pre-
scribes the rules for testing seeds of specific
species. For example, seeds of Canada bluegrass
(Poa compressa) are tested on germination paper,
at 15/25 or 15/30°C (15°C for 8 hours/30°C for
16 hours daily), with light during the 8-hour
period and potassium nitrate (KNO2) added to the
substrate. Unfortunately, for the seeds of most

wildland species, no standard germination tests
exist. The AOSA has draft standards for about
100 wildland species. Until the standards are
accepted and/or developed for the seeds of impor-
tant wildland species, germination figures as given
on seed tags are meaningless.

DETERMINING GERMI NAB I L ITY OF WILDLAND SPECIES
Af terri peni ng

The seeds of many species will not germinate soon
after they are harvested. As time passes, germi-
nabil ity of these seeds gradually increases until
they may be highly germi nable.

This time period that must pass before the seeds
will germinate has been termed the afterripening
requirement. These requirements are not respon-
sive to external stimuli. One cannot do anything
about them but wait.

This type of dormancy has been attributed to
immature embryos that require post-harvest time to
mature.

A variant of this type of dormancy is called tem-
perature-dependent afterripening. In this case,
seeds will not germinate at one incubation tem-
perature (usually moderate to high incubation
temperatures), but will germinate at other tem-
peratures (usually cold incubation temperatures).

Practically, this means the nurseryman has to wait
to obtain germination with the seeds of certain
species. Do not confuse afterripening with
stratification requirements where the dormancy
does respond to external stimuli. Stratification
requirements will be discussed later.

Hard Seed Coats

If seeds do not initially germinate or fail to
germinate after a reasonable afterripening period,
the first germination factor to check is to see
if the seeds imbibe water. This can be done by
pressing the seed with a thumbnail or by cutting.
If the interior of the seed appears chalky and
hard, water has not been imbibed through the seed
coat. Imbibed seeds should be soft and easily
squashed with the thumb.

Seeds with coats that do not freely allow the
passage of water are termed hard seeds.

Scari fi cation

To break the hard seed coats some form of scari-
fication is required. This scarification can be
accomplished with mechancial , thermal, or chemical
treatments. If the seeds are large enough, scari-
fication may be accomplished by filing a notch in
the coat or clipping so as not to injure the
embryo. Smaller seeds can be scarified by mecha-
nically abrading them in some manner. This may
be as simple as rubbing the seeds between sheets
of sandpaper.

Mechanical scarifiers have been developed with
abrasive lined drums in which the seeds are rota-
ted. Virtually any mechanical scarification that
results in increased germinabil ity results in de-
creased viability. In other words, you pay the
price for getting some seeds to germinate by
fatally injuring other seeds. Hammer mills are
used for scarifying seeds. Great care must be
taken to not excessively injure seeds with these
treatments. Minimum clearance between concave
bars in threshing machines can be used to crack
the seeds of legumes to obtain increased germina-
bil ity, but again, with some reduction in viability.

Thermal scarification is obtained by dropping seeds
into boiling water and then allowing the water to
cool. Such treatment may have many other influences
such as thermal shock to the embryo or leaching
soluble inhibitors. Thermal cracking of seed coats
is facilitated by fall seeding at shallow depths
with exposure to freezing temperatures.

Concentrated sulfuric acid is used to remove hard
seed coats. This treatment is difficult to con-
trol and may have many side effects. The duration
of treatment has to be determined for individual
seed lots. Heating from the acid reaction with
rinse water and hydrolysis of the seed tissue may
induce germination other than through the intended
increased imbibition of water.

Always try to control the temperature of the acid-
treated seeds in a water bath, rinse a small amount
of acid and seeds in a large volume of water, and
use a neutralizing solution after the treatment.

Stratification

Seeds that imbibe water but fail to germinate are
good candidates for stratification. Do not confuse
this word with scarification. Stratification in-
volves placing seeds in a wet environment at tem-
peratures that are not conducive to germination.
For most western plants these are temperatures
too cold for germination. Such treatments are
termed cool -moist stratification. The duration
of stratification requirements can range from a
few days to many months. For prolonged stratifi-
cation a substrate must be furnished for moisture
retention. Historically peat has been used.
Commonly used materials include sand and vermi-
cul i te .

Naked stratification has proven effective for the
seeds of some species of conifers. This is accom-
plished by soaking the seeds overnight in water
and then placing the damp seeds in plastic bags
that are sealed for the duration of the stratifi-
cati on .

Special stratification conditions include prolonged
soaking in refrigerated baths that are saturated
with oxygen or by using activated charcoal as a
stratification substrate.

Some species require specific stratification
temperatures. Their seeds are very difficult
to germinate without prolonged experimentation.

Nurserymen have long solved stratification pro-
blems by fall planting seeds and allowing nature
to supply the treatment. In cold areas where snow
cover is prolonged, such practices can be quite
effective. The interface between continuous snow
cover and the surface of the seedbed usually is
near 0°C, a near-ideal stratification environment.
Any interruption of temperature or moisture condi-
tions during the stratification period results in
prolonging the stratification requirement. Cover-
ing seeds in flats and covering them with sand
and placing the flats outdoors on the northside
of a greenhouse can provide a test environment
for the stratification of seeds whose requirements
are not known.

The seeds of several eastern hardwoods require
periods of warm-moist stratification for germina-
tion. Some species require warm-moist stratifica-
tion followed by cold-moist stratification.

Nitrate Ion

The most influential factor in enhancing germina-
tion of seeds is often enrichment of the germina-
tion substrate with nitrate ions. The nitrate is
usually supplied as potassium njtrate (^NCO at
concentrations ranging from 10" to 1 0 mmoles
(1.0 to 0.01 g per litter of water). In the field
or nursery bed, flushes of spring germination may
be associated with nitrification and the availa-
bility of nitrate nitrogen in the seedbed.

Gibberellic Acid

The mode of action of gibberellic acid in seed
germination is not known, but very low concentra-
tions of this growth regulator can greatly enhance
germination. Concentrations of from 1 to 250 parts
per million (p/m) are commonly used in germination
enhancement. Combinations of gibberellic acid and
potassium nitrate are often more effective than
either material alone. Both of these materials
can be obtained from chemical supply houses. The
potassium nitrate is more easily obtained than
gi bberel 1 in.

A good balance is needed for preparing the minute
concentrations of gibberellic acid. A solution
with a concentration of 1 p/m of gibberellic acid
consists of 0.001 grams of gibberellic acid dis-
solved in 1,000 milliliters of water. Gibberellic
acid is sold as a 10-percent active ingredient
preparation, which makes the weighing simpler.
One alternative is to prepare higher concentrations
than needed and dilute to the desired concentration.
For example, 1 ,000 p/m would be 1 g in 1 ,000 ml;
however, gibberellic acid is relatively expensive
and breaks down very rapidly under warm temperatures

Hydrogen Peroxide

Seeds of several species, especially members of the
rose family, have their germination enhanced by
soaking in hydrogen peroxide solutions. Dramatic
germination enhancement has been obtained with
seeds of bitterbrush (Purshia tridentata) and
curl leaf mountain mahogany (Cercocarpus ledi fol ius) .

A wide range of concentrations from 1 to 30 percent
is effective. Generally, the higher the concentra-
tion, the shorter the soaking time, but the greater
the risk of damaging the seed. Hydrogen peroxide
is a very reactive chemical. Concentrations greater
than 3 percent are particularly dangerous to handle.

Other Chemicals

A large number of other chemicals have been used
to enhance germination. These include, among
others, ethylene producing compounds and various
sulphydryl compounds.

Light

Many seeds are sensitive to light during germina-
tion. This light or phytochrome reaction involves
germination stimulation by near red light and dor-
mancy inductions by far red light. Generally cool-
white florescent light enhances germination and
incandescent light should be avoided.

Practically, seeds that require light for germina-
tion have to placed virtually on the surface of the
seedbed. The seeds should be pressed into the
seedbed for optimum moisture transfer.

Copeland, L. 0. Principles of seed science and
technology. Minneapolis, MN: Burgess Publish-
ing Co. ; 1 976. 368 p.

Emery, D. Seed propagation of native California
plants. Santa Barbara Botanical Garden Leaflet
1(10): 81-96; 1 964.

Grabe, D. F., ed. Tetrazolium testing handbook.
Contribution No. 29 to the handbook on seed
testing. Association of Official Seed Analysis;
1 970. 62 p.

Harmond, J. E.; Brandenburg, N. R.; Klein, L. J.
Mechanical seed cleaning and handling. Agricul-
ture Handbook No. 354. U.S. Department of
Agriculture; 1 968. 56 p.

Harmond, J. E.; Klein, L. M. A versatile plot
thresher. Agriculture Research Service Note
ARS 42-4-1, U.S. Department of Agriculture;
1 964. 7 p.

Harmond, J. E.; Smith, J. E., Jr.; Park, J. K.
Harvesting the seeds of grasses and legumes.
In: Seeds, the Yearbook of Agriculture; Washing-
ton, D.C.: U.S. Department of Agriculture;
1 961: 181 -188.

SEEDBED REQUIREMENTS

Seeds have to take moisture up from the germination
substrate faster than they lose it to the atmos-
phere. In a well -firmed seedbed, optimum germina-
tion conditions can occur with proper water manage-
ment. Planting small seeds on the surface of a
firmed seedbed and covering them with vermiculite
can produce a quality germination environment.

Generally only seeds with external mucilage can
germinate on the surface of seedbeds. Exceptions
are seeds such as Russian thistle (Sal sola iberica)
with extremely rapid germination.

Even seeds with extremely low percentage germina-
tion can give satisfactory establishment if
sufficient seeds are planted in a quality seedbed.

SUGGESTED READING

Bradenburg, N. R. Bibliography of harvesting and
processing forage-seed, 1949-1964. ARS 42-135.
U.S. Department of Agriculture, Agricultural
Research Service; 1968. 17 p.

Chan, F. J.; Harris, R. W.; Leiser, A. T. Direct
seeding of woody plants in the landscape.
Leaflet No. 2577. University of California,
Division of Agriculture Science; 1977. 13 p.

Colby, M. K. ; Lewis, G. D. Economics of contain-
erized conifer seedlings. Fort Collins, CO:
U.S. Department of Agriculture, Forest Service;
1973. 7 p.

Harrington, J. F. Problems of seed storage.

In: Heydecker, W., ed. Seed ecology; University
Park, PA., and London: Pennsylvania State
University Press; 1973: 578 p.

Hartman, J. T.; Kester, D. E. Sexual propagation.
In: Plant propagation--pri nci pi es and practice;
Englewood, Cliffs, N.J.: Prentice Hall; 1968:
53-188.

Hary, E. M. ; Collier, J. W.; Norris, M. J. A
simple harvester for perennial grass seeds.
Davis, CA: University of California, Agronomy
and Range Science; 1969.

Heydecker, W., ed. Seed ecology. University
Park, PA, and London: Pennsylvania State Uni-
versity Press; 1973: 578 p.

Hopkins, A. D. Periodical events and natural
law as guides to agricultural research and
practice. U.S. Monthly Weather Review Supple-
ment. 9: 5-42; 1918.

Larsen, J. E. Revegetation equipment catalog.
Missoula, MT: U.S. Department of Agriculture,
Forest Service; 1 980. 1 97 p.

McKenzie, D. W. Survey of high-production grass
seed collectors. Project Record. San Dimas,
CA: U.S. Department of Agriculture, Forest
Service, Equipment Development Center; 1977. 13 p.

Maquire, J. D.; Overland, A. Laboratory germination
of seeds of weedy and native plants. Circular
No. 349. Washington Agriculture Experiment Sta-
tion; 1 959. 1 5 p.

Mirov, N. T.; Kraebel , C. J. Collecting and
handling seeds of wild plants. Forestry Publi-
cation No. 5. U.S. Department of Agriculture,
Civilian Conservation Corps; 1939. 42 p.

Mitrakos, K. ; Shropshire, W., Jr., ed. Phytochrome.
London and New York: Academic Press; 1971. 631 p.

Nord, E. C. Bitterbrush and seed harvesting: When,
where, and how. Journal of Range Management
16: 258-261 ; 1963.

Peterson, B. 0. Bitterbrush (Purshia tridentata)
seed dormancy broken with thiourea. Journal of
Range Management 10: 41-42; 1957.

Plummer, A. P.; Christensen, D. E.; Monsen, S. B.
Restoring big-game in Utah. Utah Division of
Fish and Game Publication No. 68-3; 1 968. 183 p.

Schneegas, E. R.; Graham, J. Bitterbrush seed
collecting by machine or by hand. Journal of
Range Management 20: 99-102; 1967.

Schopmeyer, C. S., ed. Seeds of woody plants in
the United States. Agriculture Handbook No. 450,
U.S. Department of Agriculture; 1974. 878 p.

Spencer, J. S.; Rashelof, V. M.; Young, J. A.
Safety modification for operations and trans-
portation of the rangeland drill. Journal of
Range Management 32: 406-407; 1979.

Storey, C. L.; Speirs, R. D.; Henderson, L. S.
Insect control in farm-stored grain. Farmers'
Bulletin No. 2269, U.S. Department of Agricul-
ture; 1979. 18 p.

Tinus, R. W.; Stein, W. I.; Balmer, W. E., eds.
Proceedings of the North American containerized
forest trees seedlings symposium; 1974 August
26-29; Denver, CO. Washington, D.C.: Government
Printing Office, Great Plains Agricultural
Council, Publication No. 68; 1974. 458 p.

Young, J. A.; Evans, R. A.; Kay, B. L.; Owen, R. E.;
Budy, Jerry. Collecting, processing, and germi-
nating seeds of western wildland plants. ARM-W-3.
Oakland, CA: U.S. Department of Agriculture,
Science and Education Administration; 1981. 44 p.

U.S. Department of Agriculture. Woody plant seed
manual. Miscellaneous Publication No. 654; 1948.
416 p.

U.S. Department of Agriculutre. Stored-grain
insects. Agriculture Handbook No. 500, U.S.
Department of Agriculture; 1979. 54 p.

In: Murphy, Patrick M., compiler. The challenge of
producing native plants for the I n termounta i n
area: proceedings: I n termounta i n Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report I NT- 1 68 .
Ogden, UT : U.S. Department of Agriculture,
Forest Service, I ntermounta i n Forest and Range
Experiment Station; 1984. 96 p.

PRODUCING BAREROOT SEEDLINGS OF NATIVE SHRUBS
Nancy Shaw

ABSTRACT: Bareroot planting stock of native
shrub species is being requested for soil
stabilization, range and wildlife habitat
improvement, and low-maintenance landscaping
projects in the Intermountain region. Shrub
seedlings of a number of species are successfully
grown using modifications of techniques developed
for the propagation of conifers and introduced
shrubs. Refinement of techniques and solutions
to specific cultural problems in the production
of individual species should improve the quality
of stock being produced.

INTRODUCTION

Bareroot seedlings of introduced hardwood tree
and shrub species traditionally used in windbreak
and conservation plantings are routinely produced
by many Federal, State, and private nurseries.
In the Intermountain region the need, and in some
cases the legal requirement (McArthur 1981), for
native species to revegetate disturbed lands has
led to the production of a number of native
shrubs as bareroot stock. Seed and transplant
stock of species suited to specific habitat types
are needed for reclamation of disturbed sites,
range and wildlife habitat improvement, and low
maintenance landscaping.

The decision to use bareroot or container
planting stock depends upon a number of factors:

1. Species required. Although some
species are difficult to grow as
bareroot stock, others have been
successfully propagated (tables 1, 2)
using modifications of cultural
practices developed for conifers.
Information relating to the germination
and growth of related species (for
example, Rosa , Rhus , or Prunus spp. )
has also been applied. Cultural
practices are being refined based on
experience gained in growing native
plants at specific nursery sites.
Consequently, techniques and
information exist that are not
presently available in the literature.

2. Characteristics of the planting site.
Both container and bareroot seedlings
have been successfully planted on a
wide variety of wildland sites,

Nancy Shaw is a Botanist, Intermountain Forest
and Range Experiment Station, Forest Service,
U.S. Department of Agriculture, located at the
Forestry Sciences Laboratory, Boise, Idaho.

although bareroot stock generally does
not perform as well on adverse sites
(Hodder 1970), particularly rocky
areas where there is inadequate soil
to pack around the root system.

3. Scheduling. The time from seed
collection to lifting of bareroot
stock varies from approximately 11
months for fall lifting 1-0 big
sagebrush (Artemisia tridentata) to
nearly 3 years for species such as
Rocky Mountain maple (Acer glabrum)
that are lifted as 2-0 stock. For
some species sowing and lifting may
be scheduled for either fall or
spri ng .

4. Cost. Bareroot seedlings generally
cost less than seedlings grown in
containers. Consequently, their use
may often be justified economically.
Handling and transportation of
bareroot seedlings must be carefully
planned to protect plants from
desiccation and overheating before
planting (Dahlgreen 1976). However,
bareroot seedlings are much less
bulky than container seedlings, and
if adequate storage facilities are
available, they can be transported
and maintained with much less
difficulty and at a lower cost
(Stevens 1981).

PLANNING AND SCHEDULING

For both speculation and contract growing the
source of seed or cuttings should be carefully
selected. Extensive morphological and
physiological variation exists among
populations of individual native shrub species
(Stutz 1974; Blauer and others 1975; Welch and
Monsen 1981). Populations vary in their range
of adaptation, growth habit, growth rates,
pal atabi 1 i ty , nutrient value, soil stabilizing
capability, and ease of propagation. The
opportunity exists to select and market
transplants using seed or cuttings from
populations adapted to the planting site that
exhibit characteristics compatible with
specific planting goals.

Seed production of many shrub species is
erratic and scheduling problems may make seed
collection difficult. Seed of some minor
species is not harvested regularly by
commercial collectors. Seed banks may be
maintained to avoid these problems. Bareroot
stock of easily rooted species may be

propagated from cuttings if seed is unavailable
or difficult to germinate.

All steps in the propagation of each species must
be carefully scheduled. Seed and cuttings must
be collected during the appropriate season (see
Plummer and others 1968; U.S. Department of
Agriculture, Forest Service 1974; Hartmann and
Kester 1975; Vories 1981). Adequate time must be
allotted for seed processing, testing, presowing
treatments, field or laboratory stratification,
and field production. Most seedlings are lifted
after one year's growth in the seedbed, although
a few species may require two growing seasons.
Seedlings may be lifted in either the fall or
spring.

Antelope bitterbrush and other native shrubs have
been grown at the Lucky Peak Forest Service
Nursery near Boise, Idaho, during the past 10
years. Practices employed for native shrub
production at Lucky Peak will be described where
applicable throughout this paper.

SEED ACQUISITION AND PROCESSING
Purchase or Collection

Named varieties of several important native shrub
species have been released for commercial seed
production following extensive testing by the
U.S. Department of Agriculture, Soil Conservation
Service, and cooperating agencies (U.S.
Department of Agriculture, Soil Conservation
Service 1982). Seed of these releases is being
produced under agricultural conditions in seed
orchards or seed fields and is commercially
available. The characteristics and range of
adaptation of each named variety have been
carefully determined. Production of shrub seed
under agricultural conditions should result in
improved seed quality and availability as
appropriate cultural techniques are developed for
each species. Other seed sources include plants
of selected populations maintained at the
nursery, collections from selected wildland
stands, or purchases from commercial seed
dealers. Seed source information should be
provided with purchased seed. Acceptable purity
levels for seed used for wildland plantings have
been suggested by Plummer and others (1968).
Acceptable germination levels are given in table
1. Seed transfer guidelines have not been
established for native shrubs. For contract
growing, seed of populations known to be adapted
to the planting site should be obtained.

Precise timing is essential for the collection of
seed from wildland stands. Maturation dates for
individual shrub species range from May to
February (U.S. Department of Agriculture, Forest
Service 1974; Vories 1981; Wasser 1982). The
exact seed maturation date for a specific
wildland stand will depend upon its geographic
location and local weather conditions. Species
that ripen in late fall and winter must be
collected nearly a year before fall sowing. Seed
maturation in stands selected for seed collection
should be carefully monitored. Expected crops

may not develop and seed of some species such as
antelope bitterbrush or snowbrush ceanothus
(Ceanothus velutinus) is dispersed very quickly
after ripening (U.S. Department of Agriculture,
Forest Service 1974; Vories 1981).

Cleaning and Storage

Seedlots must be cleaned carefully to obtain
high purity levels. Clean seed is required to
maximize uniformity of seed placement and
subsequent seedling development in the nursery
beds. Sagebrush, rabbitbrush (Chrysothamnus
spp.), and other species are often sold at low
purities for rangeland seedings. Purchased
seed of these species may require additional
cleaning for nursery use.

Optimum storage conditions and the effect of
various storage methods on the duration of seed
viability have not been determined for most
native plant species. Dry seed of sumac (Rhus
spp.) and other species with water-impervious
seed coats will remain viable for 10 to 20
years when exposed to ambient temperature and
humidity conditions in open storage (Heit 1967;
Hartmann and Kester 1975). Stevens and others
(1981) found seed of antelope bitterbrush,
fourwing saltbush (Atriplex canescens), and a
number of other native shrub species to retain
viability for at least 15 years in open
storage. Fumigation or insecticides may be
required to prevent infestation of open-stored
seed.

Cold, dry storage increases the longevity of
most medium to long-lived seeds and is desir-
able if seeds are to be stored for long
periods. Seed should be placed in sealed,
moisture proof containers and stored at 32° to
50°F (0 to 10°C). Below freezing temperatures
(0° to 32°F [-18 to 0°C]) are most effective if
the added cost is justified. The most
effective moisture contents for cold, dry
storage of native species have not been
determined. Maximum safe seed moisture
contents for cold, dry storage of many tree
species is 9 percent. The relative humidity
(R.H.) should be less than 70 percent and, if
possible, less than 50 percent (Heit 1967;
Hartmann and Kester 1975).

Cold moist storage (32° to 50°F [0 to 10°C]) at
80 to 90 percent humidity is required for such
species as oak (Quercus spp.) and spring
ripening maple species. Seeds of these species
should not be allowed to dry prior to storage
(Hartmann and Kester 1975).

Testi ng

Purity and germination or viability tests are
used to provide an estimate of seed quality.
Seeding rates are subsequently based on these
tests plus determination of number of seeds per
pound. Purity and seed weight are obtained
following standardized procedures (A0SA 1981).
Association of Official Seed Analysts (A0SA)
standards for testing the germination of

Table 1. — Nursery production of native plant species

Species

Seed

maturation
dates

Seed Acceptable Acceptable Duration of Storage 5 g y Presowing^

cleaning^ purity j germination viability requirements ' ' treatment

(percent) (percent) (years)

Stratification5 '6
Warm Cold
(numbers of days)

Bitterbrush, 6/25-8/15 4-2-4-5
antelope

Buffaloberry, 8/1-9/30
silver

3-6-4

Ceanothus ,
redstem

7/10-8/15 6-4

Chokecherry, 7/25-9/15 3-6-4
common

Cliffrose, 7/5-8/10
Stansbury

2-4-5

Currant ,
golden

Dogwood ,
redosier

Elder,

blueberry

Ephedra,
green

Eriogonum,
Wyeth

Hawthorn,
river

7/20-8/10 3-6-4-5

8/20-9/10 3-6-7-4

8/15-9/25 3-6-4-5

7/15-9/1 6-2-4

7/25-8/20 6-2-4

8/15-10/15 3-6-7-4

Juniper, Rocky 9/1-12/30 2-6-4
Mountain

Maple, Rocky 8/1-9/30
Mountain

2-4

Mountain mahogany, 7/10-9/1 2-4-5
curlleaf

Rabbitbrush, 10/15-12/30 2-4
rubber

Rose, Woods 9/1-11/30 3-6-4

Sagebrush ,
big

Saltbush ,
f ourwing

11/5-1/15 1 or 2-4

10/20-3/1 1-4

Serviceberry , 7/10-9/15 3-6-7-4
Saskatoon

Snowberry ,
common

Sumac ,

skunkbrush

Winterf at
common

8/10-9/15 3-6-4
6/20-10/10 3-6-4
9/25-11/25 2-4

95
95
95
95
95
95
95
98
90
90

10-15

95
8-12

70
80

16+ open or cold,'

dry

11-15 cold, dry

16+ open or cold,

dry

4-6 cold, dry

16+ open or cold,

dry

16+ dry, sealed

4-6 cold, dry

16+ cold, dry

16+ open

4-6

16+ cold, dry

0-3

16+ open or cold,

dry

0-3 open

16+ cold, dry

4-6

16+ open

16+ cold, dry

7-10 open or cold,

dry

16+ open or cold,

dry

0-3 cold, dry

hot water none

H.SO. (15

2 j
mm. dry

seed only)

none

H SO
(60 min)

hot water

120

20-60

60-90

0-90

120-160

60-90

84-112

120

180

36
120

30-365
0-10

30-50

120-180

60-300

30-90

Purities listed are recommended minimum acceptable levels for rangeland seedlings (Plummer and others 1968) .

"Key: 1. Hammermill; 2. Barley debearder; 3. Dybvig with water; 4. Two screen fan machine; 5. Gravity table; 6. Dry; 7. Seed
grindermacerator . Jorgenson, K. ; Stevens, R. , Ephraim, UT: Data on file at Great Basin Experimental Area; 1982.

^Recommended minimum acceptable levels for rangeland seedings. Jorgensen, K. ; Stevens, R. , Ephraim, UT: Data on file at Great
Basin Experimental Area; 1982.

Open warehouse storage. Stevens and others (1981).

3Vories (1981).

U.S. Department of Agriculture, Forest Service (1974).

7Heit (1967).

Treatments used at Lucky Peak Nursery.

3 o o

Open storage - ambient conditions. Cold, dry storage - dried seed stored under refrigeration at 0° to 50°F (-18° to 10 C) in
sealed containers (R.H. of 70 percent or less).

Table 2. — Nursery production of native plant species .

Species

Sowing Hand
date cast

or broad-
sowing

Pruning
Top Root

Lifting
considerations

Production
period

Persistent Vegetative
leaves propagation

Special
considerations

Bitterbrush,
antelope

Fall2

Lateral roots
strip easily

1-0

Treat seed with captan

Blueberry ,
elder

Fall

Thick taproot

1-0

Stratified seed germinates
over 2-year period.

Buf faloberry ,
silver

Fall

-0 or 2-

-0

Ceanothus ,
redstem

Fall

1-0

Short seed collection period.
Insect predation of seeds
common. Seedlings subject to
damping off, stem rot.

Chokecherry ,
common

Fall

1-0

Cliffrose,
Stansbury

Fall

Lateral roots
strip easily

1-0

Currant ,
golden

Fall

1-0

Hardwood
cuttings

Dogwood,
redosier

Fall

-0 or 2-

-0

Ephedra,
green

Fall, spring

Fragile roots

1-0

Eriogonum,
Wyeth

Fall, spring

Taproot

1-0

Insect predation of seeds
c ommon .

Hawthorn,
river

Fall

1-0

Dry fresh seed several weeks
prior to acid treatment.
Seed lots frequently do not
germinate uniformly.

Juniper, Rocky
Mountain

Summer

2-0

Maple, Rocky
Mountain

Fall

-0 or 2-

-0

Mountain mahogany,
curlleaf

Fall

1-0

Rabbitbrush,
rubber

Fall, spring

(X)

Large taproot

1-0

Wildings

Rose, Woods

Fall

1-0

Sagebrush, big

Fall, spring

(X)

Large taproot

1-0

Wildings

Saltbush, fourwing

Fall

Large taproot,
brittle stems

1-0

Low seed fill.

Serviceberry ,
Saskatoon

Fall

1-0

Snowberry ,
common

Late summer,
early fall

-0 or 2-

-0

Stem
cuttings

Warm stratification more
effective than acid treat

Sumac ,

skunkbush

Fall

Large taproot

1-0

Root
cuttings

Winterf at ,
common

Fall, spring

Large taproot

1-0

Fluffy seed - not free flow-
ing.

Willow,
Scouler

Extensive
root system

1-0

Hardwood stem
cuttings

Based on production experience at Lucky Peak Nursery.

Species normally sown in fall may be artificially stratified and sown in spring.
Normally deciduous, but may retain leaves in nursery.

individual native shrub species have not yet been
established. Consequently, each seed laboratory
has developed or adopted procedures for
germinating commonly tested species.

Individual populations of a single shrub species
may vary widely in germination requirements. In
addition, the prolonged stratification periods
required to release the dormancy of many shrub
species (Vories 1981) decrease the usefulness of
germination tests. Tetrazolium chloride tests of
seed viability are frequently substituted for
germination tests. At present, tetrazolium
chloride test results for native shrubs are
generally higher and more consistent than
germination results, as not all viable seed will
germinate under the less than optimum germination
conditions provided.

Condi tioni ng

Some native shrub species require presowing
treatments to release various forms of seed
dormancy (Heit 1971; U.S. Department of Agricul-
ture, Forest Service 1974; Vories 1981; table 1).
Acid or mechanical scarification, dry heat, hot
water, hormone applications, and other chemical
treatments are commonly used. The level of
treatment required varies with accession and
condition of the seedlot.

Dormancy requirements of many native shrub
species are met by fall seeding. Heit (1968)
found fall seeding of many dormant species ful-
filled cold stratification requirements and
provided increased seedling production, more
uniform stands, maximum first year production,
and less disease loss compared to spring sowing.
He provided fall sowing recommendations for 55
shrub species. Species requiring moist, warm
stratification may be sown during the late summer
or early fall, watered, and covered with a layer
of polyethylene or other mulching material.
Artificially stratified seed of dormant species
and seed of nondormant species such as
rabbitbrush and winterfat (Ceratoi des 1 anata ) may
be sown in spring.

Seed should be artificially stratified if it is
unlikely that an adequate stratification period
would be provided in the nursery. Artificial
stratification is also an alternative if seed is
not available at the time of fall seeding or when
fall seeding is impossible due to weather
conditions. Spring sowing also provides a means
of controlling seedling size.

or greater. Other nursery drills that were
developed for conifer seed are difficult to
calibrate and cannot be used to sow
small-seeded species.

Seeding Rate

Optimum seedling densities have not been
established for native shrubs. Densities
selected depend upon the species sown,
geographic location of the nursery, size
requirements for lifted seedlings, and other
nursery conditions. Most shrubs grow rapidly
compared to conifers and can be lifted as 1-0
stock. Fourwing saltbush, blueberry elder
(Sambucus cerulea), big sagebrush and related
species develop extensively branched shoot
systems, large taproots, and spreading, lateral
root systems, particularly when grown at low
densities. Although they grow rapidly, species
such as common chokecherry ( Prunus vi rginiana)
and curl leaf mountain mahogany (Cercocarpus
ledifol ius) usually produce one main shoot and
only moderate sized root systems. Slowly
developing species such as silver buffaloberry
(Shepherdia argentea) and Rocky Mountain maple
may be lifted as 2-0 stock and are normally
planted at higher densities than species on a
1-0 rotation. Desired densities for native
plant species range from 16 to 25 per square
foot (172 to 269/m2) at the Lucky Peak Nursery.

For many shrub species, the amount of seed
required to produce a requested number of
seedlings may be only estimated. Culling rates
and seedbed mortality figures have not been
established for individual species at most
nurseries because too few seedlots have been
sown to provide adequate data. In addition,
these figures tend to vary with the seed
accessions being grown. At the Lucky Peak
Nursery, seedbed mortality for bitterbrush is
estimated to be approximately 35 percent and
the culling rate 15 percent. A seedbed
mortality figure of 40 percent and culling rate
of 20 percent are used for all other native
plant species.

The following equation may be used to calculate
the amount of cleaned seed required to grow a
specified number of plantable seedlings. Data
for typical seed lots and constants for
production at the Lucky Peak Nursery were used
to calculate the amount of seed needed to
produce 1,000 plantable seedlings of antelope
bitterbrush and fourwing saltbush.

Sowi ng

Newly developed nursery drills such as the
Love-Oyjord are capable of sowing seeds with a
wide range of sizes and shapes. Seed must be
carefully cleaned to facilitate uniform
distribution and prevent clogging of the drill
drop tubes. Seed of big sagebrush, which
averages well over 2,000,000 seeds per pound
(4,400,000 per kg) (Plummer and others 1968), for
example, can be successfully seeded through such
drills if first cleaned to a purity of 80 percent

• (lbS-} = (P)(G)(n)(l-M)(l-C)

Antelope Fourwing

Symbol s bitterbrush sal tbush

N = number of plantable seedlings

required 1,000 1,000

P = purity (decimal) .95 .95

G = germinabi 1 i ty (decimal) .90 .50

n = number of seeds per pound 21,900 58,000

M = seedling mortality (decimal) .35 .40

C = culling rate (decimal) .15 .20

Wt(lbs.) = weight of seed required to

produce N seedlings .10 lb . 08 1 b

Seeding Depth

Shrub seeds vary in size from those of the common
chokecherri es (4,790 per pound [10 538 per kg])
to rockspirea (Holodiscus discolor) (5,340,000
per pound [11 748 000 per kgj) (Grisez 1974;
Stickney 1974). Seeds should be sown at
approximately 1.5 times seed diameter, or
slightly deeper in light soils or for fall
seedings (Williams and Hanks 1976). Small -seeded
species are easily sown too deep. They should be
drilled into shallow, open furrows and mulched
lightly to regulate the planting depth.

Seed of shrubs such as winterfat and rabbitbrush
do not flow freely. These and any other species
that cannot be satisfactorily seeded with
available equipment may be hand sown in drill
marks and covered. Alternatively, seed may also
be broadcast mechanically or by hand. Small
seeds can be broadcast on a prepared seedbed and
covered using a lightweight drag. The seedbed
may be prepared using a roller, cultipacker, or
other imprinter. Trashy or fluffy seed such as
winterfat, rabbitbrush, Apache-plume, ( Fal 1 ugi a
paradoxa ) , or western virginsbower ( CI emati s
1 i gusti ci f ol i a ) can be broadcast on an imprinted
or rough surface. However, these seeds cling
together and are not effectively covered with
drags. They should be incorporated in the soil
surface by running an imprinting implement such
as a cultipacker over the seeded beds.

NURSERY CULTURE

Cultural requirements for most native shrub and
tree species have not been determined.
Practices in use include a combination of stan-
dard propagation techniques modified through
on-site experience and observations of seedling
development, growth rates, and morphological
characteristics of individual species.

Mulching

Mulching fall-sown seedbeds reduces erosion,
frost-heaving, drying, and crusting; protects
seeds from cold; and reduces weed growth.
Spring-sown seed may be mulched to retard
surface evapotranspi rati on and regulate seeding
depth. Well -watered seedbeds may be covered
with a polyethylene film or any of a variety of
materials commonly used as mulches (Hartmann
and Kester 1975). Seedbeds may be rapidly
covered by hydromul ching . Mulch net, burlap,
or snow fencing may be placed over the mulch to
protect it from high winds. Mulches provide a
uniform environment for overwinter
stratification. They may be left in place to
prevent premature germination where late frosts
are a hazard. Rapid germination results when
they are removed (Heit 1968; Hartmann and
Kester 1975; Williams and Hanks 1976).

Irrigation

Once established, many species from arid sites
require less irrigation than species from more
mesic sites. Although it may not be possible
to provide separate irrigation regimes for
individual species, it may be possible to group
species from similar vegetative communities
within compartments or nursery fields.

Throughout the germination period, the soil
surface must be kept moist to maximize seed
germination and seedling emergence. This may
be difficult to accomplish as the soil surface
is subject to wide fluctuations in temperature
and moisture supply. This problem is accentu-
ated for small -seeded species sown at shallow
depths and for seedlots with low germination
rates and long germination periods. If a
number of species are fall-planted without
mulching, germination of individual species may
occur at various times during a 2- to 3-month
period. Fall or spring mulching of fall-sown
seedbeds and removal of mulch after the danger
of spring frosts has passed serves to minimize
this problem by promoting more uniform
germination, reducing the length of the
germination period, and decreasing the length

of time the surface of the seedbeds must be kept
moist. Fungal infections are of concern in the
production of antelope bitterbrush, fourwing
saltbush, mountain mahogany, and other native
plants. Emergence may be enhanced by surface-
sterilizing the seeds or dusting the seeds with a
fungicide such as captan (Booth 1980). If
seedling mortality is noted, water should be
applied only sparingly.

Ferti 1 ization

Native plants are generally faster growing and
less demanding of nutrients than conifers. If
adequate nutrient levels are established before
seeding, deficiencies of most elements are not
likely to occur (Smith 1979). Nitrogen
applications are usually necessary, particularly
if high carbon-nitrogen ratios develop as a
result of mulching. Conifers and shrubs normally
receive similar fertilizer treatments at the
Lucky Peak Nursery. Two thousand pounds per acre
(2 245 kg/ha) of 6-2-0 Milorganite is
incorporated into the soil prior to sowing.
Ammonium nitrate (34-0-0) and superphosphate
(0-46-0) are applied as side dressings.

Weed Control

Soil fumigants may be applied to nursery beds
before shrub seeding to reduce weed problems.
However, late August or early September fumiga-
tion with methyl bromide (98 and 67 percent) at
249 and 349 lbs/acre (280 and 392 kg/ha) followed
by seeding of broadleaf species has produced
unsatisfactory results in northern Plains
nurseries (Riffle 1976). Poor seed germination
and erratic growth during the first growing
period following fumigation were attributed to
decreased endomycorrhizal spores in the soil and
endomycorrhizal development on seedlings (Riffle
1980). The use of fumigants such as Mylone that
eliminate root pathogens but are not harmful to
mycorrhizal fungi was recommended.

Most native shrub seedlings are weeded
mechanically or by hand as herbicide
recommendations are not available for individual
species. Lohmiller and Young (1972) believed
that herbicide recommendations established for
agricultural species could be transferred to
related wildland shrubs following simple testing.
They found that preemergence herbicide techniques
developed for peanuts and soybeans could be
applied to several leguminous shrubs.

Several introduced hardwood species as well as
antelope bitterbrush and common chokecherry have
been included in the Western Forest Tree Nursery
Herbicide Study (Abrahamson 1980; Ryker 1979).
Ryker (1979) found postsowing and postgermination
applications of bifenox reduced height growth of
antelope bitterbrush and common chokecherry while
postsowing and postgermination applications of
DCPA were safe for common chokecherry. Enide has
been used as a post-emergence herbicide for
antelope bitterbrush at the Lucky Peak Nursery.
Nursery managers should test promising herbicide

treatments by applying them to test plots of
individual species at the nursery site before
large scale application (Sandquist and others
1981).

Pruni ng

Many shrub species grow rapidly, producing
highly branched shoots (fourwing saltbush, big
sagebrush) or shoots with numerous large leaves
(blueberry elder, smooth sumac) during the
first growing season. Large plants dominate
smaller or later germinating seedlings,
resulting in a lack of plant uniformity. Top
pruning larger seedlings encourages more
uniform growth and improves shoot/root ratios
because smaller seedlings are released from
competition. Top pruning early in the season
promotes the development of larger branches on
the lower stems (Williams and Hanks 1976).
Seedlings may also be top or side pruned in the
nursery during the dormant season or in the
packing shed after lifting to provide a more
desirable size for packing and planting.

Roots are pruned to increase seedling
uniformity, stimulate fibrous root development,
and improve shoot/root ratios. Severing the
taproot of bitterbrush, fourwing saltbush,
blueberry elder, and other species early in the
growing season serves to stimulate lateral root
growth. The fibrous roots that develop are
stronger and less easily damaged during
lifting. Pruning taproots of rapidly growing
species one or more times during the growing
season at increasing depths (for example, 4, 6,
and 8 inches [10, 15, and 20 cm] also prevents
the development of a thick root at the normal
lifting depth. If these thick taproots are
damaged during lifting, the open wound can
easily be infected with disease organisms.

Lateral root pruning is used to increase
fibrous root development, control seedling size
and facilitate lifting. Roots of some species
(for example, shrubby penstemon [Penstemon
fruticosus] ) may intertwine in the nursery bed
and must be separated by hand during sorting.

SEEDLING HARVESTING AND STORAGE
Lifting

Shrub seedlings are frequently lifted in the
spring, and usually break dormancy earlier in
the spring than do conifers. They may also be
lifted in the fall for immediate planting, when
weather and soil conditions are favorable.
Fall lifting and overwinter storage is a third
option, especially for stock that must be
planted early in the spring before weather
conditions would permit lifting. Fall lifting
and overwinter seedling storage also serve to
reduce the spring workload and free bed space
for sowing. Seedlings should not be lifted in
the fall until they are adequately hardened by
exposure to low temperature or frosts, or
following leaf fall (Williams and Hanks 1976).

Species with fragile root systems or brittle
shoots are easily damaged during lifting,
packing, and planting. Plants that produce
extensive root and shoot systems that have not
been adequately pruned are bulky and difficult to
pack and plant without damaging the plants or
reduci ng survi val .

Gradi ng

Grading criteria have not been established for
most native plant species. If possible,
seedling specifications should be developed
with the customer before sowing. Several
factors should be considered in establishing
specifications for individual species and
orders. First, past outplanting experience may
indicate morphological or size characteristics of
seedlings that are correlated with transplanting
success. For example, Carpenter (1983)
recommends that only those antelope bitterbrush
seedlings with branched stems should be used as
this characteristic seemed to be indicative of an
adequate root system for field planting (table
3). Second, seedling size requirements are
related to planting site conditions; larger
seedlings are generally required for more
adverse sites. Third, size specifications may
be modified to fit the proposed planting
method. Seedlings with bulky root and shoot
systems are difficult to plant using standard
planting tools or mechanical tree planters.
Fourth, customers may have individual
preferences based on planting goals or past
experience.

Table 3. — Grading and first year field survival of antelope bitterbrush
seedlings at Lucky Peak Nursery. Nursery bed density 17.6
seedlings per square foot (180 seedl ings/m2 ) .

Grading Criteria

Size Class

III

Shoots

length (inches)
branching

dry wt. (g)

4.7 (4-6)
branches <l/3
length of main stem
0.5

6.5 (6-8)
branches equal
main stem length
1.2

8.8 (>8.0)
branches equal
main stem length
1.9

Roots

length (inches)
description

dry wt. (g)

9.5 (8-10)
taproot - few short
lateral roots
0.4

9.8 (8-10)
taproot - few
lateral roots
0.8

10.7 (10-12)
taproot - few
lateral roots
1.0

Outplanting

Percent of plantable
seedlings 13
survival (percent) 88

79
88

8
90

Storage

Fall -lifted seedlings of deciduous species may
be held in frozen storage at 28°F (-2°C) for
extended periods. Seedlings must be protected
from desiccation. At the Lucky Peak Nursery
antelope bitterbrush and other shrubs may be
fall-lifted for immediate planting at local
sites. Seedlings not planted are packed in
Kraft bags with polyethylene liners and stored
in coolers at 28°F for spring planting
(Carpenter 1983; Carpenter, personal communica-
tion). Fall-lifted seedlings with persistent
leaves are subject to mold infection if held in
cold storage and may be more successfully
stored by "heeling in", although the success of
this technique depends upon local weather
conditions. At Lucky Peak spring-lifted shrubs
are refrigerated at 32° to 34CF (0° to 1°C) in
Kraft bags for periods of 1 to 3 months prior
to planting.

VEGETATIVE PROPAGATION

Some species of native plants are more easily
and economically produced from cuttings than
from seed. Vegetative propagation is also used
to maintain the genetic identity of stock with
desirable characteristics. Such easily rooted
species as willows (Sal ix spp. ) , poplar
(Populus spp.), and cottonwood are often
produced from hardwood cuttings. Oldman
wormwood (Artemisia abrotanum), Absinthium (A.
absinthium), willow (Salix spp.), and currant
( Ri bes spp . ) have been grown from cuttings at
the Lucky Peak Nursery.

Hardwood or semi -hardwood cuttings of the
wormwood species root readily and may be
collected and planted immediately without
callusing. Cuttings may be made when the
plants are dormant or during the growing
season. Most species that can be propagated
vegetatively in the nursery are grown from
hardwood cuttings. Hardwood cuttings are inex-
pensive and are easily collected, handled,
stored, and propagated. Cuttings may be
collected from stands near the planting site or
from cutting blocks maintained at the nursery.
Cuttings are taken during the dormant period
from healthy, moderately vigorous plants
growing in full sunlight. Wood from the
previous season's growth should be selected.
Individual cuttings should include at least two
nodes and may be from 4 to 30 inches (10 to 76
cm) in length and from 0.25 to 1.5 inches (0.6
to 3.8 cm) in diameter (Hartmann and Kester
1975; Williams and Hanks 1976).

Cuttings of species that do not root readily
may be treated with a root-promoting substance
such as i ndol ebutyri c acid, naphthal eneacetic
acid, or indoleacetic acid. Indol ebutyri c acid
at concentrations between 500 and 10,000 ppm
(0.05 to 1.0 percent) is commonly used with
higher concentration usually being more
effective for hardwood cuttings. Fungicides
such as captan or benomyl may be applied in
combination with rooting compounds. Cuttings
should be allowed to callus for several weeks

in cold storage before planting. Dormant
cuttings are planted 2 to 4 inches (5 to 10 cm)
apart within rows of the nursery bed with at
least one bud above ground. They should be
watered frequently as roots begin to develop.
Willow, currant, wormwoods, poplar, and other
rapid-growing species can normally be lifted as
1-0 stock.

PUBLICATIONS CITED

Abrahamson, L. P.; Burns, K. F. Western forest
tree nursery herbicide study - Great Plains
segment. Syracuse, NY: State University of New
York; 1980. 49 p. 1979 progress report.

Association of Official Seed Analysts. Rules for
testing seeds. J. Seed Tech. 6(2): 1-126; 1981.

Blauer, A. C; Plummer, A. P.; Stevens, R.;

Giunta, B. C. Characteristics and hydridization
of important Intermountai n shrubs. I. Rose
family. Res. Pap. INT- 169. Ogden, UT: U.S.
Department of Agriculture, Forest Service,
Intermountain Forest and Range Experiment
Station; 1975. 32 p.

Booth, D. T. Emergence of bitterbrush seedlings
on land disturbed by phosphate mining. J. Range
Manage. 33(6): 439-441; 1980.

Carpenter, R. Artificial revegetation using
antelope bitterbrush - a land manager's view.
In: Tiedemann, A. R.; Johnson, K. L. ,
compilers. Research and management of
bitterbrush and cliffrose in western North
America; 1982 April 13-15; Salt Lake City, UT.
Gen. Tech. Rep. INT-152. Ogden, UT: U.S.
Department of Agriculture, Forest Service,
Intermountain Forest and Range Experiment
Station; 1983: 118-125.

Dahlgreen, A. K. Care of forest tree seedlings
from nursery to planting hole. In: Baumgartner,
D. M. ; Boyd, R. J., eds. Tree planting in the
inland northwest; 1976 February 17-19; Pullman,
WA. Pullman, WA: Washington State University
Cooperative Extension Service; 1976: 205-238.

Grisez, T. J. Prunus L. In: Shopmeyer, C. A.,
tech. coord. Seeds of woody plants in the
United States. Agric. Handb. No. 450.
Washington, DC: U.S. Department of Agriculture,
Forest Service; 1974: 658-673.

Hartmann, H. T.; Kester, D. E. Plant propagation.
3rd ed. Englewood Cliffs, NJ: Prentice-Hall,
Inc.; 1975. 662 p.

Heit, C. E. Propagation from seed. Part II:
Storage of deciduous tree and shrub seeds. Am.
Nurseryman 9: 12-13, 86-94; 1967.

Heit, C. E. Propagation from seed. Part 15: Fall
planting of shrub seeds for successful seedling
production. Am. Nurseryman 10: 8-10, 70-80;
1968.

Heit, C. E. Propagation from seed. Part 22:
Testing and growing western desert and
mountain shrub species. Am. Nurseryman
13(10): 10-12, 76-89; 1971.

Hodder, R. L. Roadside dryland planting

research in Montana. Highway Res. Rec. 335:
29-34; 1970.

Lohmiller, R. G.; Young, W. C. Propagation of
shrubs in the nursery. In: McKell, C. M. ;
Blaisdell, J. P.; Goodin, J. R. , tech. eds.
Wildland shrubs - their biology and
utilization; July 1971; Logan, UT. Gen. Tech.
Rep. INT-1. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain
Forest and Range Experiment Station; 1972:
349-358.

McArthur, E. D. Shrub selection and adaptation
for rehabilitation plantings. In: Stelter, L.
H. ; DePuit, E. J.; Mikol, S. A., tech.
coords. Shrub establishment on disturbed arid
and semi-arid lands; 1980 December 2-3;
Laramie, WY. Cheyenne, WY: Wyoming Game and
Fish Department; 1981: 1-8.

Plummer, A. P.; Christensen, D. R. ; Monsen, S.
B. Restoring big-game range in Utah. Publ .
No. 68-3. Salt Lake City, UT: Utah Department
of Fish and Game; 1968. 183 p.

Riffle, J. W. Effects of soil fumigation on
growth of hardwood seedlings in a northern
plains nursery. (Abstr.) Amer. Phytopathol .
Soc. Proc. 3: 215; 1976.

Riffle, J. W. Growth and endomycorrhi zal
development of broadleaf seedlings in
fumigated nursery soil. Forest Sci. 26(3):
403-413; 1980.

Ryker, R. A. Western nursery herbicide study -
1979 update. In: Proceedings of the
Intermountain Nurserymen's Association
meeting; 1979: 16-23.

Sandquist, R. E.; Owston , P. W.; McDonald, S.
E. How to test herbicides at forest tree
nurseries. Gen. Tech. Rep. PNW-127. Portland,
OR: U.S. Department of Agriculture, Forest
Service; 1981. 24 p.

Smith, E. M. Fertilizer practices for

field-grown nursery stock. Am. Nurseryman 21:
9, 62, 63, 64; 1979.

Stevens, R. Techniques for planting shrubs on
wildland disturbances. In: Stelter, L. H.;
DePuit, E. J.; Mikol. S. A., tech. coords.
Shrub establishment on disturbed arid and
semi-arid lands; 1980 December 2-3; Laramie,
WY. Cheyenne, WY: Wyoming Game and Fish
Department; 1981: 29-36.

Stevens, R. ; Jorgensen, K. R. ; Davis, J. N.
Viability of seed from thirty-two shrub and
forb species through fifteen years of
warehouse storage. Great Basin Nat. 41(3):
274-277; 1981.

Stickney, P. F. Holodiscus discolor (Pursh)
Maxim. In: Shopmeyer, C. S. , tech. coord.
Seeds of woody plants in the United States.
Agric. Handb. No. 450. Washington, DC: U.S.
Department of Agriculture, Forest Service;
1974: 448-449.

Stutz, H. C. Rapid evolution in western shrubs.
Utah Sci. 34: 16-20, 33; 1974.

Vories, K. C. Growing Colorado plants from seed:
a state of the art. Volume I: shrubs. Gen.
Tech. Rep. INT-103. Ogden , UT: U.S. Department
of Agriculture, Forest Service, Intermountai n
Forest and Range Experiment Station; 1981.
80 p.

Wasser, C. H. Ecology and culture of selected
species useful in revegetating disturbed lands
in the West. Washington, DC: U.S. Department of
Interior, Office of Biological Services, Fish
and Wildlife Service; 1982. 347 p.

Welch, B. L.; Monsen, S. B. Winter crude protein
among accessions of fourwing saltbush grown in
a uniform garden. Great Basin Nat. 41(3):
343-345; 1981.

Williams, R. D. ; Hanks, S. H. Hardwood

nurseryman's guide. Agric. Handb. No. 473.
Washington, DC: U.S. Department of Agriculture,
Forest Service; 1976. 78 p.

U.S. Department of Agriculture, Forest Service.
Seeds of woody plants in the United States.
Agric. Handb. No. 450. Shopmeyer, C. S. , tech.
coord. Washington, DC: U.S. Department of
Agriculture, Forest Service; 1974. 883 p.

U.S. Department of Agriculture, Soil Conservation
Service. Improved plant materials. Tech. Note
42. Washington, DC: U.S. Department of
Agriculture, Soil Conservation Service; 1982.
17 p. Revi sed annual ly .

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the I ntermounta i n
area: proceedings: I ntermounta i n Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report I NT - 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, I ntermounta i n Forest and Range
Experiment Station; 1984. 96 p.

PRODUCING NATIVE PLANTS AS CONTAINER SEEDLINGS
Thomas D. Landis and Edward J. Simonich

ABSTRACT: Crops of native plants should be planned
to allow enough time for seed collection, seed
processing, seed treatments and stratification,
greenhouse growth, and hardening. An ideal con-
tainer nursery consists of a production green-
house, a cold frame, a shadehouse and refrigerated
storage. Four propagation methods can be used to
produce native plants: direct seeding, germinants,
transplants, and rooted cuttings. The choice of
container should consider seedling growth, species
characteristics and outplanting site. Most native
plants can be grown reasonably well under a stand-
ard greenhouse environment and in commercial pot-
ting mixes. The type and amount of hardening will
depend on the species characteristics and the
future use of the plant. Nursery managers must be
aware of variation between species, seed sources,
and annual seed crops. Successful growers must
acquire direct experience in producing each
species under their own nursery system.

INTRODUCTION

The large scale production of native plants is
still a relatively new enterprise and the grow-
ing of container seedlings in greenhouses is the
newest production technique in western forest nurs-
eries. Producing native plants in containers is a
logical operation, however, because some species
have proven difficult to grow as bareroot seed-
lings. For example, Mormon tea (Ephedra spp.) has
very brittle stems and fragile root systems which
are sensitive to breakage during bareroot lifting
operations and the expansive root system of elder-
berry (Sambucus spp.) makes it hard to culture in
seedbeds. Other native plants such as Arizona
cypress (Cupressus avizonied) just seem to grow
better in containers.

Container seedlings have been reported to have
several advantages over bareroot seedlings such
as a shorter production period and improved sur-
vival and growth after outplanting (Stein 1974).
As already mentioned, some species are easier to
grow in containers compared to bareroot stock and
there is no root disturbance during seedling pro-
cessing. On the outplanting site, container seed-
lings suffer less transplant shock and are generally
easier to plant than bareroot seedlings. Instead
of the limited spring planting period for bareroot
trees, container seedlings have been successfully

Thomas D. Landis is Western Nursery Specialist
for the USDA Forest Service, Lakewood, Colo.
Ed Simonich is Nursery Manager for Native
Plants Inc., Salt Lake City, Utah.

outplanted during the fall and may be suitable
for other planting times as well (Stein 1974).

Although tree seedlings have been grown in con-
tainers for well over a decade, only a few nur-
series are producing native plants as container
seedlings. Compared to commercial tree species,
very little is known about the culture of native
plants in greenhouses. Many nursery managers are
reluctant to try and grow natives because they
have heard horror stories about the difficulty of
breaking seed dormancy, and the availability and
quality of native plant seeds have been unreliable.

The objective of this paper, therefore, is to
discuss some of the cultural practices useful in
growing native plants in containers. Because of
their years of experience and good reputation in
the field, the greenhouse operations of Native
Plants Inc. of Salt Lake City, Utah, will be used
as a model throughout the paper. Other pertinent
literature will be referred to whenever appropriate.

PLANNING AND CROP SCHEDULING

Before the decision is made to produce native
plants in containers, the grower should assess
the potential market. This assessment requires
business and marketing skills which are beyond
the scope of this paper. Basically, though,
there are two business approaches: (1) contract
growing, or (2) speculation on future demand.
Growing contracts are typically for a designated
number of one or more plant species which are to
be grown to certain size and quality standards by
a specified time. Speculative growing is often
risky and requires a keen appraisal of future
markets. Some nurseries like Native Plants Inc.
operate with a combination of contract and specu-
lation growing.

The market analysis should result in a list of
plant species to be produced. The grower must
next decide whether the species can best be prop-
agated by seeds or by vegetative cuttings. Seed
dealers should be consulted to determine seed
availability as some native plants do not produce
a good seed crop every year and seed of some
species does not store well. The grower must be
certain that he can secure seeds or cuttings
before proceeding with the planning process.

When the crop species have been selected, the
grower should develop detailed production
schedules that delineate the duration and sequence
of the various operations (fig« 1 & 2). Crop
planning is normally done during April or May so
that there is enough time to secure seed later
in the summer or early fall.

Jan

Feb

Mar

Apr

M a v

J u n

Jul

A u a

Sep

Oct

Nov

Dec

Plans

Collect Seed

Seed

Jan

Feb

Mar

A p r

M a v

J u n

Jul

A u q

Sep

Oct

Nov

Dec

Stratification

Greenhouse

Hardening

Jan

Feb

M a r A p r

M a v

J u n

Jul

A u q

Sep

Oct

Nov

Dec

Shadehouse

Figure 1. — Production schedule for growing native plants in containers:
creeping Oregon grape (Mahonia repens) — germinants

Jan

Feb

M a r

A p rfM a v

J u n

Jul

A u a

Sep

Oct

Nov

Dec

Plans

Collect Seed

Strat.

Jan

Feb

Mar

A p r

M a v

J u n

Jul

Aug

Sep

Oct

Dec

In Seed Trays

Transplanting

Greenhouse

Jan

Feb

Mar

Apr

M a v

J u n

Jul

Aug

Sep

Oct

Nov

Dec

Greenhouse

Hardening

Shadehouse

Figure 2. — Production schedule for growing native plants in containers:
Rocky Mountain juniper ( Juniperus scopulorem) — transplants

If seed must be procured, the total time for crop
production may take from 2 to 3 years depending
on the species of native plant and the type of
propagation system (fig. 1 & 2). These rotation
times are longer than for a typical conifer seed-
ling which may take only from 8-12 months. The
longer production period is primarily due to the
problems with seed collection and processing and
the extended stratification periods required for
many native plant species. If seed can be obtained
immediately, then the production time of some
native species can be reduced to about 1 year.
Most native plant seed can be collected and stored
ahead of time although storability varies with
species. Butterbrush (Purshia trident at a) can be
stored under refrigeration for over 10 years,
whereas prostrate summer cypress (Kochia pvostvata)
loses viability after one year (Steve Monsen, per.
comm.). For planning purposes, however, it would
be wise for new growers to allow ample time to
grow their first crop of native plants.

Compared with many greenhouse crops where the
plants are sold directly out of the production
greenhouse, native plants must be properly hard-
ened before they are suitable for sale. This
hardening period will be discussed in detail later
but normally requires at least 1 month.

PRODUCTION FACILITIES

Whereas many ornamental crops can be produced in
a single structure, the greenhouse, native plants
may require as many as four separate facilities.
An ideal container nursery consists of 1) a pro-
duction greenhouse to grow the seedlings, 2) a cold
frame or shadehouse to harden the plants 3) a shade-
house to store the seedlings until they are sold
and 4) refrigerated storage to maintain dormant
stock for late season plantings. Native Plants
Inc. has a three-structure system consisting of
greenhouses, a cold frame, and an extensive shade-
house .

The best type of greenhouse depends on several
factors but most important is the nursery climate.
Most nurseries in the Intermountain area use
fully-controlled houses which give maximum control
over the environment whereas nurseries in milder
climates may be able to use semi-controlled green-
houses. The advantages and disadvantages of
different facilities are discussed in detail in
Tinus and McDonald (1979).

One of the operational advantages of a fully-
controlled greenhouse is the production of more
than one crop per year; Native Plants Inc. is
capable of producing two to three crops of plants
per year depending on species. Some plants do not
grow well during the winter season when day
length is short and light intensities are low.
Squawbush {Rhus trilobata) is very sensitive to
photoperiod so crop lights are necessary to pro-
duce multiple crops (Steve Monsen, pers. comm.).
Desert species just naturally grow better during
the summer season.

The optimum size of greenhouse for producing native
plants will vary, depending on the need for sepa-
rate growing environments and the cost and opera-
tional difficulties of maintaining individual
houses. Small, separate greenhouses permit the
nurseryman to generate a range of environments
and are also better for multiple cropping because
species with different growing requirements can
be sown and hardened at different times during the
season. Separate houses allow more flexibility
because the nursery manager can shut down some of
his greenhouses and grow a smaller crop more
economically. A single, large greenhouse can be
designed with moveable curtains to produce com-
partments with different environments but the
crop lights and irrigation system should also be
under separate controls. On the other hand,
larger houses are generally cheaper to heat and
maintain, and less expensive to build than a
range of smaller greenhouses.

PROPAGATION METHODS

The choice of propagation method is probably one
of the most critical phases in native plant pro-
duction. The majority of seedlings in forest nurs-
eries are produced by direct seeding but the
stringent stratification requirements and limited
availability of many native plant seeds may require
other approaches.

Native Plants Inc. uses four different methods to
propagate woody plants in containers: direct
seeding, gerrainants, transplants, and rooted cut-
tings (table 1). Some species such as pinyon
pine (Pinus edulis) are only produced by one method
(seed) whereas others such as common juniper
(Juniperus communis) can be propagated by gerrain-
ants or cuttings. The choice of propagation
method also has its economic considerations.
Direct seeding is the cheapest method because of a
lower labor requirement compared to the rooted cut-
ting technique which is more labor intensive and
requires special facilities.

Direct seeding is defined as the sowing of seed
into the growth container and is the standard
technique for most conifer species and wildf lowers.
This propagation method is limited to those spec-
ies with little or no dormancy requirement which
works out to about 10 percent of the species pro-
duced at Native Plants Inc. The advantages and
disadvantages of this method are given in table
1. If a stratification period or other pre-
treatment is specified, then the seed is treated
prior to the planned sowing date. Otherwise, the
seed is generally soaked in room temperature
water for 24-48 hours and surface dried before
sowing.

The seeding procedure begins with the calculation
of the proper sowing density based on germination
tests and past experience. Generally several
seeds are sown per container and are later thinned
to one seedling per cell. Because of the irregular
shapes and sizes of most native plant seeds, most
sowing is done by hand although a shutterbox or

Table 1. — Properties of four propagation methods for producing native plants in containers

Propagation Technique

Advantages

Disadvantages

1. Seeds - Direct sowing of

• Quick

• Hard to control cell occupancy

seed to growth

* Minimal handling of seed

and seedling density

containers

• Sowing can be mechanized

' Requires thinning and consolidation

* Uniform crop development

* Inefficient and costly use of seed

* Greenhouse time lost prior to

emergence

2. Germinants -

Sowing
germinated
seed from
stratification
into growth
containers

Control of cell occupancy
and seedling density

Efficient use of valuable
seed

Good use of greenhouse
space

Accommodates variable
germination rates

Sowing is slow and involves skilled
labor

Irregular germination rate may cause
variation in crop development

Number of seedlings subject to
quality of seed lot

Requires specialized stratification
chambers

Transplants

Seedlings are
grown in trays
and transplanted
to growth
containers

• Control of cell occupancy

and seedling density

• Efficient use of valuable

seed

• Good use of greenhouse

space

• More uniform crop

development

• Can use natural or arti-

ficial stratification

Transplanting is slow and involves

skilled labor
Requires additional operation of

sowing seed trays
Overly dense seed trays could lower

seedling vigor or lead to disease

problems

Rooted cuttings -

Vegetative
cuttings are
rooted in
trays and
transplanted
to growth
containers

Control of cell occupancy
and seedling density

Not dependent on seed
crops

Good use of greenhouse
space

Ability to preserve
desirable genetic
characteristics

Some species can be pro-
duced more quickly

Maintain sexual character-
istics of dioecious
species

Transplanting is slow and involves

skilled labor
Some species do not root well
Requires special facilities
Most costly technique

vacuum seeder could be used for certain species
and large seed lots. The sown seed is usually
covered with some type of material such as per-
lite or grit to hold the seed in contact with the
potting soil and retard evaporation and algae
growth.

The success of the direct seeding method is
dependent on the accuracy of the seed information.
Germination tests vary from lab to lab and no
standardized tests are available for many native
shrubs and forbs. Laboratory germination tests
are run under ideal conditions and therefore test
results may differ from greenhouse germination.
Sometimes the seed is obtained just before the
sowing date and so there is not enough time for
seed testing.

The germinant technique is defined as the sowing
of pregerrainated seed into the growth container.

This propagation method is best for plants with
simple dormancy requirements and species with
seeds too large to handle mechanically. It is
particularly suitable for seed lots of variable
or unknown quality because only good seed is
sown in the growth container. Cell occupancy
is maximized with this method as there are few
blank cells and no subsequent thinning is needed.
The germinant technique is used for about 15 per-
cent of the native plant species produced at Native
Plants Inc. The advantages and disadvantages are
listed in table 1 and a sample production schedule
is given in fig. 1.

The germinant procedure requires clean seed so
seed lots should be surface sterilized with chlorox
or Captan to reduce molding during stratification.
The seeds are usually hydrated with a 24-48 hour
soak and then prepared for the stratification
chamber .

Seed can be germinated in "naked" stratification
where the bare seeds are kept in a plastic bag or
mixed with a moisture-holding material such as
peat moss. Native Plants Inc. uses a fine-
textured, sterile peat moss, mixes the seed with
the moss, and places the mixture in a plastic bag
in a refrigerator at 30° to 40° F (-1° to +4° C) .
The acid peat moss helps retard seed molds during
the lengthy stratification period which can last
up to 8 months. The stratification bags should
be checked at least weekly until germination
begins. Seeds are ready to transfer to the growth
container when a white radicle becomes visible
but before the radicle becomes so long that it is
easily damaged. Cracked seeds are not necessarily
germinating; some species of seed swell and crack
long before the radicle begins to emerge. Choke-
cherry (Prunus virginiana) seeds may take several
months to produce a radicle after the seed intially
cracks .

The planting operation consists of pouring the
stratified seed out in a tray and picking out the
germinants by hand or with tweezers. The germin-
ants are placed in a depression or small hole in
the potting soil in the growth container and
covered with grit or perlite. Seeds should be
placed with the radicle oriented downward; if the
radicle is pointed upward it will reverse itself in
response to gravity which may result in a stem
crook in the young seedling. The crews at Native
Plants' greenhouse have been able to achieve pro-
duction rates of 1500-2000 plants per person-day
using this procedure. It is a good idea to double
sow the last couple of rows of containers in each
tray to provide extra seedlings to transplant
back into any empty cells.

Once all the germinants have been planted out of
the tray, the seeds are placed back into the
stratification bag and returned to the refriger-
ator. The planting crews go through the strati-
fication bags three times per week until the
germination rate begins to decline. These bags
have been maintained for as long as 8 months for
some species (eg. Prunus spp.) and germinating
seed can be used as long as mold does not be-
come a problem.

Transplants are the third propagation method used
at Native Plants Inc. and account for 65 percent
of the species produced. Transplants are defined
as seedlings which are grown to the cotyledon
stage in trays and then transplanted into growth
containers. This propagation method is best for
woody plants with complex dormancy requirements
or for species such as quaking aspen whose small
seeds would be almost impossible to plant by hand.
This technique is ideal for seed lots of variable
or unknown quality. A list of the advantages and
disadvantages of the transplant method is given
in table 1 .

The transplant trays are filled about 2 inches
(5 cm.) deep with standard potting mix and broad-
cast seeded by hand. Very small seed can be
applied through a large salt shaker to ensure
even seed distribution. Cover the seed with a
light application of a fine-textured material
such as sand-blasting grit.

Seeds that require stratification are sown in the
fall, irrigated, and placed outside in a sheltered
location and protected against dessication. This
outside storage allows the seed to naturally
stratify over winter. When the trays are brought
into the greenhouse in the spring, the seeds
germinate readily and can be immediately trans-
planted. A growing schedule for this propagation
method is given in fig. 2.

For seeds that do not require stratification, the
transplant trays are taken directly into the green-
house. In the greenhouse, the transplant flats
are kept moist by frequent hand irrigation and
germination usually occurs in 1-2 weeks. Once the
seedlings grow to the cotyledon stage and begin to
grow primary leaves, they are ready for trans-
planting. The transplanting procedure consists of
working the seedlings loose from the soil, making
a dibble hole in the potting soil of the growth
container, and transplanting a seedling into the
hole. The potting soil is then firmed around the
seedling and the growth containers are irrigated
and moved to the greenhouse benches. An experi-
enced worker can transplant up to 2,000 seedlings
in an 8-hour day.

When all the seedlings have been removed from the
transplant trays, the soil is mixed, the trays
irrigated, and the plants allowed to sprout again.
Depending on the germination rate, the trays may
produce up to three successive crops of transplant
material .

Rooted cuttings are the final propagation method
for native plant production. This technique con-
sists of rooting vegetative cuttings in trays and
transplanting them to growth containers. Approx-
imately 10 percent of the species grown at Native
Plants Inc. are produced by cuttings which is the
best method for plants that are difficult to grow
from seed or for which seed is difficult to obtain.
The advantages and disadvantages of rooted cuttings
are listed in table 1. At the Native Plants Inc.
greenhouse, rooted cuttings are used as a last
resort when the species cannot be reliably pro-
duced by another propagation technique; based on
their cost figures, rooted cuttings are four to
five times as expensive to produce as seedlings.

The production of rooted cuttings requires a spe-
cial propagation facility which at Native Plants
Inc. consists of a separate greenhouse with heated
benches and a special misting system to control
relative humidity. The cutting room is maintained
at 70 to 75° F (21 to 24° C) and humidities appro-
aching 100 percent. The atomized misting system is
designed to maintain high humidities without over-
watering the media in the cutting trays because fun-
gal diseases quickly become damaging under saturated
soil conditions. Supplemental lighting is used to
extend normal day length and permit the production
of rooted cuttings year round.

Cuttings are normally collected from plants in the
field. The best season for collection depends on
the species. Cuttings of two species of saltbush
(Atriplex cuneata and A. con fevti folia) rooted
best when collected in spring or summer but the
rooting percentage dropped markedly when cuttings
were taken in the fall (Richardson and others
1979). Cuttings of some species such as big sage-
brush {Artemisia tvidentata) root better when
collected during winter dormancy (Alvarez-Cordero
and McKell 1979).

Native Plants Inc. currently collects most of
their cutting material from "mother plants" which
are older plants from the production stock at the
nursery. To prevent disease spread, these mother
plants are sprayed with a broad spectrum fungicide
prior to collecting cuttings. Richardson and
others (1979) reported that cuttings from green-
house-grown plants rooted considerably better than
field-collected cuttings for greasewood
(Savcobatus vevmicu latus J , a species that is nor-
mally difficult to propagate vegetatively .

A good step-by-step procedure for collecting cut-
tings is described by Norris (1983). Cuttings
should be collected early in the day from new
growth of active, healthy plants. Cutting the
stem at an angle increases the surface exposure
to increase new root production sites. All
leaves should be removed from the lower third of
the cutting and the cuttings should be kept in a
shady, moist location. The crews at Native
Plants Inc. prefer to plant the cutting the same
day as it is collected.

Before the cuttings are planted, they are often
treated with a special hormone to stimulate pro-
duction of root primordia. These "rooting" chemi-
cals can be made from scratch by mixing indolebutyric
acid (IBA) with common talc, or you can buy commer-
cial products such as Rootone or Hormodin. The
best concentration of rooting hormone depends on
many variables but, in general, the more difficult
the plant is to root the higher the concentration
of rooting chemical that should be used (Norris
1983). The rooting success of big sagebrush cut-
tings increased with increases in IBA concentra-
tion from 0.0 to 2.0 percent (Alvarez-Cordero
and McKell 1979).

Treated cuttings should be inserted to a depth of
1 to 2 inches (2.5 to 5 cm) into a well-drained
medium in a shallow rooting tray. The best media
for rooting cuttings is subject to debate. Norris
(1983) recommends a 1:1 ratio of peat to perlite
or peat to fine sand. Native Plants Inc. uses
different grades of sand and several combinations
of sand, perlite, and potting soil. More informa-
tion is needed on the best rooting media for
different native plant species. Generally, the
rooting medium does not contain any type of ferti-
lizer because of a possible stimulating effect
on disease organisms.

Some cuttings root quickly so it is important to
begin checking the cuttings after the first week.
Typically, the cuttings "callus-over" first and
then produce adventitious roots from the callus
tissue. Some cuttings such as those of juniper

take as long as 6 months to root, so the cuttings
should be inspected regularly for rooting or dis-
ease problems. Cutting success can exceed 95 per-
cent with some species and Native Plants Inc. has
achieved 75 to 100 cuttings per sq. ft. (6.9 to
9.3 per sq . m) of bench space.

The rooted cuttings should be transplanted immedi-
ately into a dibble hole in the growth container
being careful to protect the new roots from
injury. The transplanting procedure is inherently
slower than any of the propagation methods using
seeds but it is possible to reach up to a 95
percent success rate if the transplanting is
performed conscientiously. The transplanted
cuttings are grown under the standard greenhouse
environment with special attention to irrigation
during the initial period.

Another technique for producing cutting material
involves the use of root sprouts. Species that
regenerate by root suckers such as quaking aspen
(Populus tvemuioid.es) can be propagated by plant-
ing sections of lateral roots in an optimum en-
vironment and harvesting the succulent sprouts
(Schier 1978). The excised roots are cut into
6 inch (15 cm.) sections and covered with potting
media in a shallow tray and placed in the green-
house. After several weeks, root sprouts will
appear. These sprouts are cut off, treated with
rooting hormones, and transplanted to a growth
container. This technique is an effective way to
propagate certain species but is quite costly in
terras of the labor requirement.

PROPAGATION OF SELECTED NATIVE PLANT SPECIES

The propagation techniques used by Native Plants
Inc. for 23 native plants are provided in table 2.

The stratification periods recommended in Seeds
of Woody Plants in the United States (USDA 1974)
illustrate the wide ecotypic variation in some
species (e.g. Woods rose, 30-365 days) and lack
of data for other species. The propagation
methods listed are those most commonly used and
some native plants can be propagated by more than
one technique. Certain species are produced more
easily during a particular season in the green-
house whereas others can be grown any time during
the year. Cropping time indicates the amount of
time required to produce a saleable plant in the
greenhouse and varies from 3-16 months.

GROWTH CONTAINER AND POTTING MEDIA

The best size, shape, and volume of growth container
for producing a native plant that will survive and
grow well in the field is a subject that is still
open to debate. Ferguson and Frischknecht (1981)
recommended a container that is 6 to 8 in. (15
to 20 cm) deep and has a volume of 15 to 25 cu.
in. (245 to 410 cu. cm.). Barker and McKell (1979)
grew four-wing saltbush (A. caneseens) and grease-
wood in four sizes and types of containers ranging
from 6 to 70 cu. in. (98 to 1147 cu. cm.) and
found that shoot length, shoot biomass, and root
biomass all increased with size of container.

Table 2 - Propagation procedures for selected native plants

Species

Production Scheduling
Stratification Propagation Cropping
Period (Days)-*-/ Method^/ Season-^/ Time (mos)

Acer civcinatum, vine maple '

120-240

1 1 G,

1 Spring |

4-5

Amelanchiev alnifolia, serviceberry ! ;

120-180+

1 1 G,

1 Any

3-4

Arctostaphylos spp., manzanita

0-210

1 1 T,

1 Any

4-6

Avtemesia tridentata, big sagebrush

0-10

1 1 T,

Spr, Sum |

3-4

Atviplex eanesoens, fourwing saltbush

30-50

1 1 T,

| Spr, Sum |

3-4

Cevcocavpus montanus, mountain mahogany

30-90

1 1 G

1 Any

4-6

Chvy sothanmus nauseosus, rabbitbrush

0-120

1 1 T

| Spr, Sum |

3-4

Cowania mexicana, cliff rose

1 1 G,

| Spr, Sum |

6-8

Ephedra viy-idis, Mormon tea

1 1 T,

[ Summer

4-6

Junipevus scopulovum, Rocky Mountain juniper

240

1 1 T

| Spr, Sum |

12-16

Firms monophylla, singleleaf pinyon [

28-90

1 1 s

| Any

8-12

Populus angustif olia, narrowleaf cottonwood

1 1 T,

| Summer

3-4

Populus tvemuloides, quaking aspen

1 1 T,

| Spr, Sum |

3-4

Potentilla f vuticosa, shrubby cinquefoil

1 1 T,

1 Any

3-5

Pvunus virginiana, chokecherry

120-160

1 1 G,

' 1 Any

3-5

Puvshia tvidentata, bitterbrush

60-90

1 1 G,

I Any

4-8

Quevcus gambelii, Gambel oak

1 1 G,

| Fall |

6-8

Phus tvilobata, skunkbush sumac

30-90

1 1 G,

1 | Any

4-6

Rosa woodsii, Woods rose

30-365

1 1 T,

| Spr, Sum [

3-5

Sambuous cevulea, blue elderberry

30-210

1 1 T,

! I Spring

3-5

Shepherdia avgentea, buffaloberry

0-90

1 1 T,

1 | Summer

4-6

Symphoricavpos oveophilus, mountain snowberry | |

60-300

1 1 T,

1 1 Spring |

4-6

Yucca glauca, yucca

1 1 s

| Spring

4-6

1/ USDA-FS. 1974. Seeds of woody plants in the
2/ S = seed; G = germinants; T = transplants; C =
3/ Spr = Spring crop; Sum = Summer crop

United States
cuttings

Agric. Handbook No. 450. 883 p.

They concluded that, all other things being equal,
these two native plants should be grown in the
largest container possible.

The best container size for good field performance
is not necessarily the best container for seedling
growth in the greenhouse. Plants grown in large
capacity containers generally perform best in the
field but require too much greenhouse space and
are costly to handle and ship. The best container
also varies with plant species and environmental
and soil conditions on the outplanting site.

Native Plants Inc. uses two different "tubepak"
containers for most of their species: the 6-pack
containers contain 13 cu . in. (213 cu. cm.) and
the 5-pack has a capacity of 17 cu. in. (279 cu.
cm.). Most species can be grown satisfactorily in
the 13 cu. in. container but many broadleaved
species have to be produced in the larger cells
because their large leaves intercept irrigation
and shade out adjacent seedlings. Some native
plants such as elderberry (Sar^bucus spp.) and

mountain-ash (Sorbuc spp.) have massive root
systems that require larger capacity containers.
The density or spacing of the containers in the
rack is also important because some species do not
grow well at higher densities. Obviously, more
work is needed to determine the best container to
use for each of the native plant species.

Based on their experiences at the Native Plants'
greenhouses, most natives grow quite well in stand-
ard potting mixes. Native Plants uses a mixture
of equal portions of four materials: peat moss,
vermiculite, perlite, and composted bark. They
also incorporate a starter fertilizer mix (Osmocote
14-14-14) into the potting soil at 10 lbs. per
cu. yd. (7.6 per cu. m.) and Micromax at 1.5 lbs
per cu. yd. (1.1 per cu. m.)to supply micro-
nutrients .

The potting mix should be near pH 5.5 and have
an electrical conductivity (E.C.) reading of less
than 2.0 mmhos .

Other researchers have reported on potting mixes
for native plants. Ferguson and Monsen (1974)
found that mixes containing peat moss and verrai-
culite produced better mountain-mahogany
(Cereocarpus ledifoti-us) seedlings compared to
those containing sand. The SEAM project at the
Coeur d'Alene nursery produced 40 different spec-
ies of native plants using a standard 1:1 mix of
peat moss and vermiculite. Ferguson (1980) stud-
ied 39 different potting media and found that no
one mix was consistently superior. He did report
that a potting mix of 50 percent peat moss, 30
percent arcillite aggregate and 20 percent vermi-
culite is recommended for Bonneville saltbush
(A. bonnevillensis) and possibly other plant spec-
ies native to alkaline soils. Mixing native soil
into standard potting mixes can increase growth
of some chenopod species (Monsen, pers. comm.).
A survey of nurseries growing desert shrubs
reported a wide variety of potting mixes that
contained such diverse components as sand, cinder,
peat moss, composted bark, charcoal, sawdust,
vermiculite, perlite, and native soil (Anon.
1979). Obviously, there is much variation in
potting mixes but it appears that standard
commercial potting soils are suitable for most
native plants although special mixes may be desir-
able for some species.

GREENHOUSE CULTURE

Native shrubs have been found to grow well under
normal greenhouse environments. Native Plants Inc.
uses a uniform environment with day temperatures
of 80°F (27°C), night temperatures of 65°F (18°C),
a relative humidity of 30-40 percent, 800-1500 ppm
carbon dioxide and a 24-hour intermittent photo-
period of 40 ft. candles. The SEAM project at
Coeur d'Alene nursery maintained a greenhouse
temperature of 65°F (18°C) for the entire growing
cycle and intermittent photoperiod lights (20
sec. every 3 min.) at an intensity of 20-40 ft.
candles. Monsen (pers. comm.) stresses that many
native plants are very sensitive to photoperiod
and so greenhouses should have continuous lighting
systems .

Fertilization at the Native Plants' greenhouse is
applied by two methods, Osmocote 14-14-14 ferti-
lizer is added to the potting soil and Peters
20-20-20 soluble fertilizer is injected through
the irrigation system. The injected fertilizer
is not applied at any standard rate but is custom-
applied based on experience. Because of the wide
variation in nutrient requirements between the
different native plant species, the grower must
visually monitor the growth and color of the
plants and fertilize based on experience.

Other greenhouse growers also emphasize the bene-
fits of fertilization of native plants. The SEAM
project applied all their nutrients through the
irrigation system using a commercial 20-20-20
mix at a 1:100 injection ratio. This solution
was applied weekly at the rate of 2 lbs. of fer-
tilizer per 500 ft. (0.9 kg. per 46 sq. m.) of
bench space. Once the desired top growth was
achieved, the fertilizer mix was changed to a
15-30-15 mixture. Ferguson and Monsen (1974)

grew mountain-mahogany seedlings with 3 different
rates of Osmocote 18-6-12 slow release fertilizer
ranging from 1 to 4 oz per cu. ft (34 to 102 g.
per 0.03 cu. m.) of potting soil and found no
significant growth differences between the rates.

THE HARDENING PHASE

The hardening phase is one of the most overlooked
yet most critical periods in the growing cycle.
It is relatively easy to produce an acceptable
plant in the greenhouse but these plants are
worthless unless they are properly conditioned so
that they can survive and grow on the planting
site. Many native plant species grow very rapidly
under the optimal conditions in the greenhouse but
this rapid growth consists of relatively large
cells with thin cell walls and little tolerance to
cold temperatures. Unlike most ornamental crops,
native plants cannot be sold directly out of the
greenhouse but must undergo a period of hardening.
Ferguson and Monsen (1974) stated that the proper
amount of cold hardening was one of the most
difficult problems in the container production
of native plants.

Hardening can be defined as the process in which
growth is reduced, stored carbohydrates accumulate,
and the plant becomes better able to withstand
adverse conditions (Penrose and Hansen 1981).

There are three major objectives of the hardening
phase :

1. To minimize physical damage during
handling, shipping, and planting.

2. To condition the plant to tolerate cold
temperatures during refrigerated storage
or after outplanting.

3. To acclimatize plants to the outside environ-
ment and satisfy internal dormancy requirements
of some species.

The type and amount of hardening depends on the
individual species characteristics and the future
use of the plant. Native plants produced as
ornamentals usually require much less hardening
compared to plants produced for a high elevation
revegetation project. The two most important
factors to consider in designing a hardening
program are the planting date and the climate of
the outplanting site. Most greenhouse nurseries
are located at low elevations where the growing
season begins earlier than at higher elevation
planting sites. Native plants that will be planted
in an environment that is similar to that where
they were grown may only require a 4-6 week
period of hardening. Plants that are outplanted
at higher elevations during spring or fall must
be able to tolerate colder temperatures and
perhaps even frost.

Dormancy is another term that is often used in
conjunction with hardiness. Dormant conifer seed-
lings have been shown to have the ability to
produce abundant new roots when planted in a
favorable environment. This high "root growth

capacity" should increase the ability of seedlings
to survive and grow on harsh sites. The role of
dormancy and root growth capacity has not been
studied for most native plants. Plants stored
under refrigeration for extended periods should
also be dormant to minimize respirational heat
build-up in the storage bags. Both dormancy and
cold hardiness can be induced by proper scheduling
of the hardening regime.

Hardiness should be induced in stages and the
process usually takes at least 6-8 weeks. The
hardening begins in the greenhouse by shutting
off the photoperiod lights and carbon dioxide
generators and leaching excess nutrients out of
the potting media. Night temperatures are de-
creased and the seedlings are fertilized with a
low nitrogen/high phosphorus and potassium fertil-
izer. Some growers also induce a mild level of
moisture stress between irrigations which sup-
posedly prepares the plant for the droughty
conditions on the outplanting site. Drought
stressing should be carefully monitored, however,
because overly dry potting soil may be difficult
to rewet and stressed plants may not cold harden
normally. In the final hardening stages, temper-
atures are gradually lowered to the freezing level
and tolerant plant species may even be taken
slightly below 32°F (0°C).

Hardening can be achieved in either of two
structures, a cold frame or a shadehouse. Shade-
houses are generally used to harden crops that
are taken out of the greenhouse in summer or
early fall when freezing temperatures are not
expected. The shadehouse consists of a frame
structure that is covered with snowfence or shade-
cloth and is equipped with an irrigation and
fertilizer injection system. Seedlings are
protected from wind, intense sunlight, and light
frosts in a shadehouse and usually continue to
produce new roots and increase in stem diameter
during favorable weather. The shadehouse also
provides a good overwintering environment and
such plants are well hardened by the following
spring and ready for planting.

The cold frame used at Native Plants Inc. is a
modified greenhouse structure which is maintained
at low temperatures to promote hardening. Cold
frame hardening is often necessary for crops that
need to be removed from the greenhouse during
freezing weather. Often, cold frames are used
to induce dormancy and cold hardiness in plants
before they are moved to a shadehouse for final
hardening and storage.

VARIATION BETWEEN SPECIES AND BETWEEN CROPS

Although it is possible to grow several species
of native plants under a standard greenhouse
environment, nursery managers should be cognizant
of the variable growth requirements and morpho-
logical characteristics of the individual species.
A grower must directly experience how plants
perform under his own nursery system before he
will be able to consistently produce uniform
crops of native plants.

Individual species will not grow the same during
different growing seasons or during different
years. Some species that grow best during the
summer season will not perform satisfactorily if
grown over the winter. Because of differences
in seed crops from year to year and between seed
sources, every crop of native plants will be
slightly different in growth characteristics.

CONCLUSIONS

1 . Crop planning is very important when working
with native plants and a crop may take from
2 to 3 years to produce if seed is not
immediately available.

2. Production of native plants may require as
many as four separate facilities: production
greenhouse, cold frame, shadehouse, and
refrigerated storage.

3. Four propagation methods are used to produce
native plants in containers: direct seeding,
germinants, transplants, and rooted cuttings.

4. The best size, shape, and volume of growth
container is dependent on the species of
plant and characteristics of the outplanting
site .

5. Standard potting mixes are adequate for many
native plants but some species may require
special mixes.

6. Native plants grow well under normal green-
house environments but a grower should be
aware of individual species differences.

7. Plants should be hardened in several stages by
changing the growing environment and moving
them to either a cold frame or shadehouse.

8. There is considerable variation between in-
dividual species and between seed collections
and so each crop of native plants will perform
differently.

PUBLICATIONS CITED

Alvarez-Cordero , E.; McKell, C. M. Stem cutting
propagation of big sagebrush {Artemisia
tvidentata Nutt.) J. Range Manage. 32(2):
141-143; 1979.

Anonymous. Soil mixes for greenhouse and nursery
growth of desert plants. Desert Plants 1(2):
82-89; 1979.

Barker, J. R.; McKell, C. M. Growth of seedling
and stem cuttings of two salt-desert shrubs in
containers prior to field planting. Reclamation
Review 2: 85-91; 1979.

Ferguson, R. B. Potting media for Atviplex
production under greenhouse conditions. Res.
Note INT 301. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain
Forest and Range Experiment Station; 1980. 7 p.

Ferguson, R. B.; Frischknecht , N. C. Shrub estab-
lishment on reconstructed soils in semi-arid
areas. In: Stelter, L.H.; DePuit, E. J.;
Mikol, S. A., ed. Shrub establishment on dis-
turbed arid and serai-aird lands: proceedings;
1980 December 2-3; Laramie, WY. Laramie, WY:
Wyoming Game and Fish Dept. 1981: 57-63.

Ferguson, R. B.; Monsen, S. B. Research with
containerized shrubs and forbs in southern
Idaho. In: Tinus, R. W.; Stein, W. I.; Balmer,
W. E., ed. Proceedings of the North American
Containerized Forest Tree Seedling Symposium;
1974 August 26-29; Denver, CO. Great Plains
Agricultural Council Publication No. 68;
1974: 349-358.

Norris, C. A. Propagating native plants from seeds
and cuttings. Amer. Nurseryman 157(9): 100-105;
1983.

Penrose, R. D.; Hansen, D. I. Planting techniques
for establishment of container-grown or bareroot
plants. In: Stelter, L. H.; DePuit, E. J.; Mikol,
S. A., ed. Shrub establishment on disturbed arid
and semi-arid lands: proceedings; 1980 Dec. 2-3;
Laramie, WY. Laramie, WY: Wyoming Game and Fish
Dept.; 1981: 37-46.

Richardson, S. G.; Barker, J. R.; Crofts, K. A.;
Van Epps, G. A. Factors affecting root of stem
cuttings of salt desert shrubs. J. Range Mgmt .
32(4): 280-283; 1979.

Schier, G. A. Vegetative propagation of

Rocky Mountain aspen. Gen. Tech. Rep. INT-44.
Ogden, UT : U.S. Department of Agriculture,
Forest Science, Intermountain Forest and
Range Experiment Station; 1978. 13 p.

Stein, W. I. Improving containerized reforestation
systems. In: Tinus, R. W.; Stein, W. I.; Balmer,
W. E., eds. Proceedings of the North American
Containerized Forest Tree Seedling Symposium.
1974 August 26-29; Denver, CO. Great Plains
Agr. Council Publ. No. 68.; 1974: 434-440.

Tinus, R. W. ; McDonald, S. E. How to grow tree
seedlings in containers in greenhouses. Gen.
Tech. Rep. RM-60. Ft. Collins, CO: U.S. Depart-
ment of Agriculture, Forest Service, Rocky
Mountain Forest and Range Experiment Station;
1979. 256 p.

USDA Forest Service. Seeds of woody plants in the
United States. Agr. Handbook 450. Washington
D.C.: U.S. Department of Agriculture, Forest
Service; 1974. 883 p.

OTHER GENERAL REFERENCES

Vories, K. C. Growing Colorado plants from seed:
a state of the art. Vol. 1 - Shrubs. Gen.
Tech. Rep. INT-103. Ogden, UT: U.S. Department
of Agriculture, Forest Service, Intermountain
Forest and Range Experiment Station; 1981. 80 p

Wasser, C. H. Ecology and culture of selected
species useful in revegetating disturbed lands
in the West. FWS/0BS-82/56 . Washington, DC:
U.S. Department of Interior, Fish and Wildlife
Service; 1982. 347 p.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT- 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

USE OF SHRUBS ON MINE SPOILS
Stephen B. Monsen

ABSTRACT: Mine disturbances can often be
revegetated through natural plant succession.
Plants that spread well by natural seeding can
be used to seed mine spoils. Transplanting
shrubs and herbs on mine sites hastens plant
establishment and improves productivity and
species diversity. However, shrub species
differ in their ability to establish and
survive as transplant stock. Therefore,
planting sites must be prepared to accommodate
direct seeding or transplanting. Environmental
conditions of the planting site dictate the
type of material and methods of planting.
Existing herbaceous vegetation must be
controlled to allow shrub seedlings to become
established .

INTRODUCTION

Rehabilitation of mined land normally requires
planting a combination of herbs and woody
species. Natural invasion of native plants
onto mined sites usually occurs too slowly to
acceptably restore the site (McKell and Van
Epps 1981). Planting is required to provide
soil protection (Packer and others 1981),
reduce the spread of weeds, and provide herbage
and habitat to animals (Monsen and Plummer
1978) .

Plantings also serve to establish a desirable
and compatible array of species that will
provide initial cover and ultimately develop a
stable community (Laycock 1980).

Mined lands are generally harsh sites and
plantings are not always successful. Seeding
or transplanting may fail even when adapted
species are used. Considerable differences
exist between the microsites and soil
conditions of mine spoils compared to
undisturbed locations (Sindelar 1980).
Consequently, it is difficult to determine the
adaptability of individual species to mined
land environments.

Species that are climax plants of undisturbed
communities often are planted on mine spoils.
Unfortunately, not all species that are
regarded as climax, and usually considered
desirable plants, are able to grow on
disturbances (Eberly and Dueholum 1979;
McGinnies and Nicholas 1980) . Usually climax
plants become established after the site has
been modified by pioneer species. Many species
that are initially adapted to mine spoils are

Stephen B. Monsen is Botanist/Biologist,
Intermountain Forest and Range Experiment Station,
Forest Service, U.S. Department of Agriculture,
located at the Intermountain Station's Shrub
Sciences Laboratory, Provo, Utah.

considered weedy plants. These may persist for
only a short time, but are useful to initiate
plant succession (Stark 1966).

Species that are adapted to a wide range of
soils, temperature extremes, and moisture
conditions are the most successful species for
harsh sites (Stark 1966). However, ecotypic
differences occur within most species. Each
ecotype is adapted to a particular range of
conditions, and if planted within its natural
range the selection will do well. If moved to
unnatural conditions specific ecotypes often do
not always survive (Plummer 1977).

Few plants have been specifically selected for
their adaptability to mine disturbances. Only
a limited number have been fully evaluated for
their performance and survival on mine spoils.
Most species that are currently used are native
or introduced species that have been used
mostly for other purposes. However, research
has determined that certain species are adapted
to infertile soils, and can be used on mined
and associated disturbances (Stark 1966; Aldon
and Pase 1981) .

NATURAL INVASION OF PLANTS

Weedy annuals and short-lived perennial herbs
are the principal species that invade most
mined lands (Howard and Samuel 1979). However,
some important woody plants also spread rapidly
onto abandoned mines (Butterfield and Tueller
1980). Many plants are adapted to mine
disturbances but spread very slowly by natural
means. Invasion by plants is often hindered by
factors related to seed production (Plummer
1977), seed germination, and seedling survival
(Sabo and others 1979). The quality and
quantity of seed produced on wildlands varies
greatly and can be influenced by unpredictable
climatic conditions and insects (U.S.
Department of Agriculture 1974).

Winds, overland flow of water, and rodents are
agents that carry seeds onto mine sites. Under
wildland conditions rodents not only distribute
but plant many seeds (West 1968). A high
proportion of seed produced in wildland stands
is consumed by animals including rodents
(Bradley 1968). The excess is all that remains
to perpetuate the species.

Rodents usually collect and store seeds of
large fruited species and seed that consists of
an edible endosperm. Usually, seeds that
remain viable for an extended period are stored
as caches in the soil surface by rodents for
later consumption (Sherman and Chilcote 1972).
Seeds planted as rodent caches frequently are
not eaten but germinate later to form a cluster
of new seedlings. Shrub seeds that are

normally gathered and stored in caches include:
antelope bitterbrush (Purshia tridentata) ,
desert peachbrush (Prunus f asciculata) , green
ephedra (Ephedra viridis) , Martin ceanothus
(Ceanothus martinii) , Saskatoon serviceberry
(Amelanchier alnif olia) , and Woods rose (Rosa
woodsi) .

Rodent activity is usually confined to areas
offering overstory protection. However, rodent
populations and habitat are not always
decreased by clearing the vegetation (Turkowski
and Reynolds 1970). Yet, small animals usually
do not venture onto barren mine wastes or
exposed sites. As sites become vegetated,
rodents inhabit the area. Once plants that are
established on the mine begin to bear seeds,
rodents gather the fruits and help further the
species and progress of successional stages in
plant development.

A substantial amount of seed is produced by
certain plants. Clean seed yields have
exceeded 300 pounds per acre (338 kg/ha) for
antelope bitterbrush grown on a planted site
near Boise, Idaho. During years of high seed
production many species increase dramatically
due to the planting efforts of small rodents.
Adapted shrubs and herbs can be selectively
located on mined sites to provide rodent
habitat, regulate their distribution, and thus
advance the spread of select species.

Small seeded species and appendaged seeds are
widely distributed by wind (Mirov and Kraebel
1939). Although a high proportion of weedy
species is spread by the wind, many useful
species are also dispersed by this method.
Wind-carried seeds often spread plant species
quickly, and populate otherwise inaccessible
sites. Species that are successfully spread by
wind include: Apache-plume (Fallugia
paradoxa) , sagebrush (Artemisia spp.),
penstemon (Penstemon spp.), and rabbitbrush
(Chrysothamnus spp . ) .

CONDITIONS INFLUENCING ARTIFICIAL SEEDING

Mined lands are usually planted soon after
mining is completed. Disturbances primarily
consist of overburden material or tailings
composed of unconsolidated soil materials.
Although topsoil and fertilizer may be added,
mine spoils usually lack soil structure and
particle aggregation that contribute to a
optimum seedbed condition. Soil drainage,
aeration, microorganism content, nutrient
balance, and organic matter are all poorly
developed for supporting a combination of
plants (Frischknecht and Ferguson 1979).

Although fresh mine spoils are usually less
productive than undisturbed sites, cultural
practices often are not employed to improve
tilth and productivity before planting.
Therefore, planted species must be adapted to
infertile sites, and capable of developing
concurrently as young seedlings.

Grasses, broadleaf herbs, and woody species are
often planted together. Assembly of a mixture
of plants with different growth forms creates
serious problems of competition among young
seedlings. Mixed plantings favor herbs over
shrubs and trees (Jensen 1980).

Grasses that are currently seeded on most mined
sites are derivatives formulated for high
germinability and seedling vigor. These highly
competitive grasses develop much faster than do
most native shrubs or trees. Grasses and many
forbs not only germinate earlier than most
shrubs, but attain a mature status much sooner.
Most seeded grasses reach maturity in 1 to 3
years. In contrast, shrubs may require 5 to 10
years to attain a sufficient size to be fully
competitive (Plummer and others 1968). During
this interim, the developing shrubs are
subjected to extensive competition, and plant
losses are common (Booth and Schuman 1981). To
be fully competitive with grasses, seeded
shrubs and trees must possess the following
traits: (1) seeds must germinate readily, (2)
seedlings must develop rapidly, (3) seasonal
growth periods should be compatible with the
seeded herbs, and (4) developing plants must
remain competitive.

Shrubs that can survive and develop
satisfactorily by direct seeding are species
that would not usually be grown as transplant
stock. Some plants can justifiably be
transplanted or direct seeded. Seeding is
usually much cheaper and easier to accomplish.
Some useful shrubs that can be successfully
seeded include: basin big sagebrush (Artemisia
tridentata tridentata) , low sagebrush
(Artemisia arbuscula) , f ourwing saltbush
(Atriplex canescens ) , winterfat (Ceratoides
lanata) , snowbrush ceanothus (Ceanothus
velutinus) , rubber rabbitbrush (Chrysothamnus
nauseosus) , Wyeth eriogonum (Eriogonum
umbellatum) , prostrate summer cypress (Kochia
prostrata) , antelope bitterbrush, and thinleaf
alder (Alnus tenuif olia) .

Natural plant succession and edaphic changes
that occur after mined sites are initially
planted change the growing conditions and
productivity of the disturbance. Some species
that have been difficult to establish initially
on fresh mine spoils by direct seeding or
transplanting have been successfully
established at a later date. New shrub and
tree seedlings are frequently encountered as a
result of natural reproduction, beginning 5 to
10 years after a site has been reclaimed. The
encroachment often occurs on sites dominated by
a competitive understory of herbs. However,
the environment of some disturbances is so
harsh that only a limited number of species
establish and persist. Little improvement can
be expected for a considerable period of time
on these areas.

The success of most plants has been based upon
the response attained from plantings
established on newly exposed mine spoils.

Unfortunately many useful species are often
discarded due to failures from initial
plantings. Growing conditions improve as soil
nutrients build up or the soil microflora is
established .

VALUE OF TRANSPLANT STOCK

Although plants may be successfully established
by direct seeding, transplanting is also a
viable revegetation technique. Some species
that establish readily by seeding do not grow
rapidly enough to provide initial ground cover
for soil stabilization (Shaw 1981). Some
species that may fail to establish or perform
satisfactorily by direct seeding can be
transplanted. This has been particularly
evident with Woods rose and chokecherry (Prunus
virginiana melanocarpa) planted on phosphate
mines in southeastern Idaho. Seedlings of both
species germinated erratically and young plants
were weak and slow to develop. Although
plantings have been established on topsoiled
and fertilized sites, the growth performance of
these small seedlings has remained unchanged.
However, 2-0 transplants of both species
developed rapidly.

Transplants that are properly spaced can
provide an immediate and effective cover.
Transplanting can be effectively used to
stabilize erodible sites and promote the
natural establishment of understory species.
Megahan (1974) reported that over 50 percent of
surface erosion from roadfills was controlled
by planting 1-year-old bareroot stock of
ponderosa pine (Pinus ponderosa) .

Transplants can also be used to control the
establishment and spread of weeds. In
contrast, shrub and tree transplants may also
promote the establishment of some understory
species. Ponderosa pine transplanted along
steep roadcut and fill slopes in central Idaho
stabilized the sites and served as a nurse crop
for understory herbs (Monsen 1974). The
presence of the overstory canopy of Woods rose,
blueberry elder (Sambucus cerulea) , and redstem
ceanothus (Ceanothus sanguineus) also aids in
the establishment of other species. Shrubs and
trees that may persist for only a few years can
be highly useful in the development of
satisfactory cover.

Some leguminous and nonleguminous shrubs and
trees are beneficial in improving soil
nutritive levels. Klemmedson (1979) reported
that eight genera of shrubs are able to fix
nitrogen through actinomycete nodulation.
These species can be used as companion plants
to improve the performance of various
understory herbs. Species of Ceanothus have
been successfully used for this purpose on mine
spoils in Idaho (Monsen 1974). Langkamp and
others (1979) reported that reestablishment of
a nutrient bank would occur slowly with the use
of Acacia (Acacia pellita) , and that pasture
legumes would rapidly rebuild nutrient levels.

Transplants can be used to increase the rate of
plant succession. In addition, transplant
stock matures quickly and community changes
occur rapidly. If persistent and compatible
species are planted initially, a predesigned
community structure can be arranged. This is
an important feature, as many planted species
do not attain full prominence until a mature
and stable plant composition is achieved.

FACTORS AFFECTING TRANSPLANT SUCCESS

Factors that affect transplant survival are
similar to those that influence seedling
establishment. However, a significant
difference is that transplanting usually
eliminates the need for a prepared seedbed.
The principal factors that reduce transplant
survival are: (1) planting unadapted species
and ecotypes; (2) carelessness in planting; (3)
insufficient soil moisture resulting from
inadequate site preparation and planting at the
wrong time of year; and (4) use of poor quality
planting stock.

Planting Adapted Species and Ecotypes

Species that are reared and planted on wildland
sites in the West normally include selections
that are native to the planting site. Seed and
vegetative cuttings often are collected from
the planting area. If this is not possible,
stock is obtained from similar vegetative types
growing in separate areas. In addition,
various grasses, forbs, and shrubs have been
developed for rangeland plantings.

However, few native or introduced species have
been specifically developed for mined sites.
Although numerous plants have been established
on mined lands, their persistence and areas of
adaptability have not been fully determined.
Considerable differences have been recorded in
the survival and initial growth rates of
ecotypes when planted on mined sites.
Different strains or ecotypes of many native
shrubs could be used to select sources that
have vigorous seedling adaptability to
infertile soils.

Growers should be aware of the differences that
occur among ecotypes of a particular species,
and seek to raise stock that is adapted to
specific soil and climatic conditions. Mined
sites should be evaluated before planting to
assure that adequate time is given to program
the vegetation efforts, collect sufficient
adapted seed, and rear transplant stock.

Plants that inhabit the site before mining may
not be adapted to the mine spoils. Present
State and Federal laws often require mining
companies to restore native plant species to
reclaimed areas. Although the use of adapted
native plants is often advisable, many mined

sites are not capable of immediately sustaining
the dominant species of the undisturbed site.

Some species and ecotypes are currently
available that are adapted to mined lands, and
these should be promoted and used. Research is
needed to develop additional plants adapted to
mined sites. A classification system needs to
be developed to identify plant selections for
disturbed situations. The system currently
used in reforestation makes use of soil types,
elevation, and climatic zones in selecting
adapted ecotypes for planting. These features
should also be applicable in delineating plants
for mined lands, although the edaphic
conditions of mine spoil are not entirely
comparable to undisturbed soils. However,
mining does not completely alter climatic and
biotic influences. Consequently, plants that
are components of original sites are still
candidates for initial revegetation trials.
Equally important is the identification of
individual species that possess inherent
characteristics that contribute to the range of
adaptation of the species. For example, the
occurrence of different subspecies, ecotypes,
and kinds of sagebrush offers a wide diversity
of planting stock suited to different site
conditions (McArthur and others 1974). Through
careful selection, adapted ecotypes of other
species can be used to revegetate mine spoils.

Site Preparation and Planting

Transplanting does not require the intensive
surface preparation treatment required for
direct seeding, yet most mines usually utilize
both revegetation techniques. Surface tillage
and fertilization are required to enhance the
survival of the seeded species. Seeding is
frequently done to control soil erosion and
surface runoff. Transplanting may be
superimposed over the existing seeding. This
usually does not create serious problems if
transplant needs are recognized.

Transplants can usually compete with newly sown
grass. However, if the grass is heavily seeded
and fertilized, shrub transplants may suffer
(Jensen 1980). Therefore, to improve shrub and
tree survival the seeding should not be at a
high rate. Fertilization of herbaceous species
should be applied at a low rate, yet the
seeding can be refertilized after the shrubs
are well established.

Mine spoils should be treated to aid plant
survival. Compact soils should be ripped to
allow infiltration, aeration, and root
development. Transplants should also be
fertilized. Fertilizer tablets placed in the
planting hole significantly aided tree growth
in an Idaho trial (Megahan 1974) .

Woody species that grow slowly and require 2 or
3 years to fully establish should be
interspaced in strips or clearings separate
from more competitive species (Giunta and
others 1975). The planting areas should be

delineated according to site conditions to
assure that species are planted in adapted
locations. It is not necessary to plant the
entire site in a grid pattern. Species can be
transplanted in groups, clusters, or mixes to
provide diversity.

Planting Quality Stock

The development of high-quality transplant
stock is essential to plant survival on mine
wastes. Specimens that are poorly developed
succumb quickly to adverse conditons. Failure
to acquire and plant quality stock accounts for
many planting failures.

Growers frequently produce a uniform grade of
planting stock. Materials are grown to 1-0 or
2-0 size classes. Container-grown stock is
also produced in rather uniform grades. Plants
can be grown to different age and size classes,
but this is difficult to program for a mine
location when only a short rearing time is
available .

The size and type of transplant is vital to
plant survival. Species that grow rapidly will
normally survive and grow well if a healthy 1-0
transplant is used. Other species grow slowly,
requiring a year or two to fully establish and
begin any appreciable growth. Green ephedra,
mountain snowberry (Symphoricarpos oreophilus) ,
mountain-ash (Sorbus scopulina) , roundleaf
buffaloberry (Shepherdia rotundif ilia) ,
skunkbush sumac (Rhus trilobata) , and spiny
hopsage (Grayia spinosa) do poorly when planted
as 1-0 stock, but perform much better when
planted as 2-0 or larger stock. Survival rates
improve and growth is markedly increased.

Proper maintenance and field planting of a
well-conditioned transplant is essential to
plant survival. Shrubs such as Wyeth
eriogonum, bush penstemon (Penstemon
f ruticosus) , and prostrate ceanothus (Ceanothus
prostratus) begin growth early in the season
and must be lifted and planted as dormant
stock, otherwise survival is very low.

Container-grown stock or ball and burlap
materials are useful in planting rocky sites.
However, high-quality bareroot stock will
perform satisfactorily. Planting large pads
and root sections as wildlings has proven
successful with species of aspen (Populus
tremuloides) , oak (Quercus spp.), and other
plants (Crofts 1978).

Mine plantings require special attention.
Sites often are rocky and planting is impared.
Without particular care, plants may fail simply
because of poor handling. Care must be taken
to follow normal planting guides.

PUBLICATIONS CITED

Aldon, E. F. ; Pase, C. P. Plant species

adaptability on mine spoils in the Southwest:
a case study. Res. Note RM-398. Fort Collins,
CO: U.S. Department of Agriculture, Forest
Service, Rocky Mountain Forest and Range
Experiment Station; 1981. 3 p.

Booth, Terrance D. ; Schuman, Gerald E. Shrub
reestablishment research at the High Plains
Grasslands Research Station. In: Stelter, L.
H.; DePuit, E. J.; Mikol, S. A., tech. coord.
Proceedings, shrub establishment on disturbed
arid and semi-arid lands; 1980 December 2-3;
Laramie, WY. Cheyenne, WY: Wyoming Game and
Fish Department; 1981: 81-88.

Bradley, Glen W. Food habits of the antelope
ground squirrel in southern Nevada. J.
Mammal. 49(1): 14-21; 1968.

Butterfield, Richard I.; Tueller, Paul T.

Revegetation potential of acid mine wastes in
Northern California. Reclamation Rev. 3:
21-31; 1980.

Crofts, Kent A. Coal mine reclamation in

Colorado. In: 32nd annual report, vegetative
rehabilitation and equipment workshop; 1978
February 5-6; San Antonio, TX. Missoula, MT:
U.S. Department of Agriculture, Forest
Service; 1978: 43-45.

Eberly, L. W. ; Dueholm, K. H. A program to
reestablish and study prairie grassland and
assess effect of fire. J. Minnesota Acad.
Sci. 45(2): 8-11; 1979.

Frischknecht , Neil C. ; Ferguson, Robert B.
Revegetating processed oil shale and coal
spoils on semi-arid lands. Interim report,
Interagency Energy /Environment R&D Program.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, and U.S. Environmental
Protection Agency; 1979. 47 p.

Giunta, B. C. ; Christensen, D. R. ; Monsen, S.
B. Interseeding shrubs in cheatgrass with a
browse seeder-scalper. J. Range Manage. 32:
398-402; 1975.

Howard, G. S.; Samuel, M. J. The value of

fresh-stripped topsoil as a source of useful
plants for surface mine revegetation. J.
Range Manage. 32: 76-77; 1979.

Klemmedson, J. 0. Ecological importance of
actinomycete nodulated plants in the western
United States. Bot. Gaz. 140 (Suppl.):
591-596; 1979.

Jensen, Bernie. Mine and roadside revegetation
in Montana. In: Proceedings of Intermountain
Nurseryman's Association and Western Forest
Nursery Association. Gen. Tech. Rep. INT-109.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and
Range Experiment Station; 1980: 129-134.

Langkamp, Peter J.; Swinden, Lindsay B. ;
Dalling, Michael J. Nitrogen fixation
(acetylene reduction) by Acacia pellita on
areas restored after mining at Groote
Eylandt, Northern Territory, Aust. J. Bot
27: 353-361; 1979.

Laycock, W. A. What is successful

reclamation? — a look at the concepts of
adaptability, productivity, cover, and
diversity of seeded species. In: Northwest
Colorado land reclamation seminar. I:
proceedings; 1980 November 18; Steamboat
Springs, CO: 1980: 1-17.

McArthur, E. D. ; Giunta, B. C. ; Plummer, A. P.
Shrubs for restoration of depleted ranges and
disturbed areas. Utah Sci. 35: 28-33; 1974.

McGinnies, W. J.; Nicholas, P. J. Effects of
topsoil thickness and nitrogen fertilizer on
the revegetation of coal mine spoils. J.
Environ. Qual. 9: 681-685; 1980.

McKell, C. M. ; Van Epps, G. A. Comparative

results of shrub establishment on arid sites.
In: Stelter, L. H. ; DePuit, E. J.; Mikol, S.
A., tech. coord. Proceedings, shrub
establishment on disturbed arid and semi-arid
lands; 1980 December 2-3; Laramie, WY.
Cheyenne, WY: Wyoming Game and Fish
Department; 1981: 138-154.

Megahan, Walter F. Deep-rooted plants for

erosion control on granitic road fills in the
Idaho Batholith. Res. Pap. INT-161. Ogden,
UT: U.S. Department of Agriculture, Forest
Service, Intermountain Forest and Range
Experiment Station; 1974. 18 p.

Mirov, N. T. ; Kraelbel, Charles J. Collecting
and handling seeds of wild plants. Civilian
Conservation Corps Forestry Publ. No. 5
Washington, DC: U.S. Department of
Agriculture, Forest Service, California
Forest and Range Experiment Station; 1939. 42
P-

Monsen, S. B. Plant selection for erosion
control of forest roads of the Idaho
Batholith. Pap. 74-2559. Chicago, IL:
American Society of Agricultural Engineers;
1974. 18 p.

Monsen, S. B.; Plummer, A. P. Plants and
treatments for revegetation of disturbed
sites in the Intermountain area. In: Wright,
R. A., ed. The reclamation of disturbed arid
lands. Albuquerque, NM: University of New
Mexico Press; 1978: 155-174.

Packer, P. E. ; Clyde, C. C. ; Israelson, E. ;
Farmer, E. ; Fletcher, J. Erosion control
during highway construction-A manual of
principles and practices for erosion.
Washington, DC: National Academy of Science,
Transportation Research Board; 1981. 36 p.

Plummet", A. P. Revegetation of distrubed

Intermountian area sites. In: Thames, J. L.,
ed. Reclamation of use of disturbed land in
the Southwest. Tucson, AZ : University Arizona
Press; 1977: 302-339.

Plummer, A. P.; Christensen, D. R. ; Monsen, S.
B. Restoring big game range in Utah. Publ.
68-3. Salt Lake City, UT: Utah Division of
Fish and Game; 1968. 183 p.

Sabo, D. G. ; Johnson, G. U. ; Martin, W. C. ;
Aldon, E. F. Germination requirements of 19
species of arid land plants. Res. Pap.
RM-210. Fort Collins, CO: U.S. Department of
Agriculture, Forest Service, Rocky Mountain
Forest and Range Experiment Station; 1979. 26
P-

Sherman, Robert J.; Chilcote, William W.

Spatial and chronological patterns of Purshia
tridentata as influenced by Pinus ponderosa .
Ecology. 53(2): 294-298; 1972.

Shaw, Nancy. Propagation and outplanting shrubs
on mine sites. In: Stelter, L. H. ; DePuit, E.
J.; Mikol, S. A., tech. coord. Proceedings,
shrub establishment on distrubed arid and
semi-arid lands; 1980 December 2-3; Laramie,
WY. Cheyenne, WY: Wyoming Game and Fish
Department; 1981: 47-56.

Sindelar, B. W. Achieving revegetation
standards on surface mined lands. In:
Adequate reclamation of mined
lands? — symposium; Billings, MT; 1980:
22-1—22-15.

Stark, N. Review of highway planting

information appropriate to Nevada. College of
Agriculture Bull. No. B-7. Carson City, NV:
Desert Research Institute, University of
Nevada; 1966:1-290.

Turkowski, Frank J.; Reynolds, Hudson G.
Response of some rodent populations to
pinyon-j uniper reduction on the Kaibab
Plateau, Arizona. The Southwestern Nat.
15(1): 23-27; 1970.

U.S. Department of Agriculture, Forest Service.
Seeds of woody plants in the United States.
In: Shopmeyer, C. S. , tech. coord.;
Agricultural Handbook No. 450. Washington,
DC: U.S. Department of Agriculture, Forest
Service; 1974. 883 p.

West, Neal E. Rodent-influenced establishment
of ponderosa pine and bitterbrush seedlings
in central Oregon. Ecology. 49(5): 110-1011;
1968.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman' s
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT-168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

TOWARD PRODUCING DISEASE-FREE CONTAINER-GROWN NATIVE WILDLAND PLANTS

David L. Nelson

ABSTRACT: Methods and a fundamental philosophy
for producing healthy planting stock of native
wildland plants are presented. Drawing from
the experience of agriculture, horticulture,
and forestry, cultural and biological disease
control methods are reviewed. The focus is
placed on certification of planting materials,
producing pathogen-free propagules, greenhouse
design and management for disease prevention,
controlling pathogens in plant growing medium,
the role of native-host genetic variability,
and managing biological control of soil-borne
diseases .

INTRODUCTION

Interest is increasing rapidly in using native
wildland plants to revegetate disturbed areas
and improve wildlife and livestock ranges in
the western United States. Producing healthy
planting stock can enhance these activities.
It is important to know when to take action in
preventing and controlling diseases of plants.
It is generally believed that if a disease is
present it will be obvious and the plant will
die, or if it does not die then it must not
have a disease. A plant without obvious
disease symptoms is not necessarily a
disease-free or pathogen-free plant. There are
also examples of viruses, bacteria, fungi, and
nematodes that affect roots only slightly. The
only visible injury is reduced top growth.
Probably as much damage results from these
"root nibblers" as from virulent pathogens that
induce obvious symptoms and kill plants
rapidly. Fungicidal treatment to prevent
seedling diseases such as damping-off often
only suppresses the pathogen which later
induces further disease in the container plant
or in the field after outplanting (Baker 1965) .

A wise approach is to adopt rigid disease
prevention methods regardless of present known
disease problems. Currently, little if any
research effort is directed toward controlling
diseases in the production of wildland planting
stock. The purpose here, therefore, is to
relate facets of existing knowledge developed
over the years in the horticultural and
agricultural experience that may be of value in
the wildland plant scene.

David L. Nelson is plant pathologist,
Intermountain Forest and Range Experiment
Station, Forest Service, U.S. Department of
Agriculture, located at the Shrub Sciences
Laboratory, Provo, Utah.

Becoming aware is a major step in preventing
plant disease problems. A long-standing
principle in plant pathology is that action
must be taken in advance to prevent disease
problems. The goal of producing disease-free
planting stock is also a responsibility, from a
biological standpoint, that must be considered.
There are several basic reasons for emphasis on
producing disease-free planting materials.
Clearly, the production of healthy planting
stock is essential. It is important to avoid
introduction of seed-borne pathogens to new
field sites via planting stock. After
outplanting, failure of the plant from a
disease that did not express obvious symptoms
during container culture is an important but
more subtle problem. The responsibility to
produce disease-free stock extends beyond the
marketing stage of containerized plants.

How can an emerging native wildland plant
industry organize itself to discharge this
responsibility? Through an interaction of
private, State, and Federal interests, an
improved certification program should be
developed. Certification of various plant
attributes is already in progress at State and
private concerns, plant introduction stations,
and plant material centers across the West.
The purpose here is to stress certification
against plant disease. Benefits can be
realized. Disease prevention should focus on
certification in three basic areas: (1)
seed-borne and vegetative-propagule-borne
pathogens, (2) producing disease-free planting
stock, both bare-root and containerized, and
(3) a rigidly defined and controlled genetic
base for seed collections.

Various methods have been used to prevent plant
disease in container-grown planting stock.
These methods have included seed certification,
cultural sanitation, chemical seed treatment,
pesticidal drenches, soil fumigation, heat
treatment of planting media, vegetative
propagule disease indexing, apical shoot tip
culture, biological control, and pathogen
suppressive growing media. These constitute a
broad area of information; and this discussion
will be limited primarily to cultural and
biological means of producing disease-free,
container-grown wildland plants.

CULTURAL CONTROL

Sanitation is the most important single
guideline in the cultural control of plant
disease problems of container-grown plants,

Sanitation is essential in the production,
collection, cleaning, storage, and germination
of seed. Sanitation also is an essential
factor in maintaining greenhouse and shadehouse
environments and in seedling transport and
planting .

Pathogen-free Plant Propagules

Use of pathogen-free seed is an obvious first
step in controlling diseases in container-grown
plants as well as in nursery or direct field
seeding. Several good references on seed-borne
pathogens are: Baker 1956, 1972; Baker and
Smith 1966; and Harman 1983. Plant pathogens
may accompany seed independently as spores,
resting structures, host debris, infested soil,
and nematode galls. They may be carried
passively, attached to the surface of seed or
fruit parts, or they may be carried internally,
imbedded in host seed tissue.

Seed dissemination of pathogens is a natural
biological mechanism that has evolved as a mode
of transmission in space, from season to season
and from plant generation to generation.
Seed-borne pathogens are not always
transmitted, but when they are, they are
usually a source of severe loss. Viruses are
frequently seed transmitted. They usually
infect gametes and persist during seed
development. Mechanically transmitted viruses
infest seed coats and are then transmitted to
seedlings. Bacteria commonly infect developing
embryos. They also enter the seed through the
funiculus and reside in cavities of the seed
coat or on outer layers of the embryo and
endosperm. Fungi have numerous mechanisms for
infecting seed and transmission to seedlings.
The smuts of grasses invade embryos, and Fungi
Imperfecti commonly infect seed coats and
pericarps .

Injuries to seed during cleaning, for example,
cracked seed coats, serve as entry points for
both seed and plant pathogens and should be
avoided. Pathogen propagules such as the
sclerotia (ergots) of Claviceps and seeds of
Orobanche and Cuscuta that accompany seed can
be removed by separation during seed cleaning.
Externally borne pathogens can usually be
controlled by surface chemical treatment, but
internally borne pathogens are more difficult
to control requiring penetrating chemicals. To
some extent thermotherapy has been successful
in killing internally borne pathogens. Hot
water, dry hot air, and aerated steam have been
used effectively to eliminate pathogens.
Aerated-steam treatment of seed has promising
advantages (Baker 1969). Temperature can be
controlled more accurately, seeds are left
drier, there is less leaching, there is less
damage to seeds, and the margin between
pathogen thermal death point and seed damage is
wider .

culture, indexing and certification.
Certification programs should be organized to
establish tolerance levels for seed-borne
pathogens. In the emerging native wildland
seed industry what is the status of knowledge
on seed-borne pathogens? Has action been taken
to establish even the potential of what is
inevitable? In the wildland scene a sound
program must begin with gaining knowledge of
seed-borne pathogens and their recognition by
the collector.

Greenhouse design

Having achieved acceptable control of seed-
borne pathogens, the focus can then turn to
seed germination and growth of containerized
plants in greenhouse culture. Commonly, if not
almost universally, prevention of plant disease
is not considered in the design of greenhouses.
Here again, enhancing sanitation to reduce
sources of contamination should be the
guideline. Greenhouses and adjoining
headhouses are seldom designed by persons with
insight into plant disease prevention.
Although elaborate systems can be devised to
exclude pathogens for special purposes,
relatively simple design considerations can
make big improvements in routine operations.

Contamination can be avoided or greatly reduced
if, in the headhouse, container and equipment
cleaning and preparation and media treatment
activities are in a room separate from
container filling and planting activities.
These rooms should be separated by a buffer
room to reduce contaminate passage. A
vestibule should join the headhouse and
greenhouse planting growing rooms to allow
independent access to rooms with distinct
activities (fig. 1). The usual
single-room thoroughfare type headhouses or
separate buildings that require outside
transport of materials to greenhouses are
unacceptable because contamination is likely.

HEADHOUSE

GREENHOUSE

Filling
and
Planting

Buffer
Room

Cleaning

and
Media

Preparation

CO
>

Growing
Room

Corridor

Growing
Room

Prevention of seed-borne pathogens begins in
the field with production of disease-free
plants. Other methods include apical meristem

Figure 1. --Basic headhouse-greenhouse design for
plant disease prevention.

Figure 2.--A greenhouse bench designed to prevent plant disease. Note bench sides are not fixed to
board support pipes, and removable boards act to minimize accumulation of debris.

Container filling and planting operations
should not take place in greenhouse growing
rooms because soil or other planting media
spillage serves as an organic substrate for
growth of pathogens on greenhouse floors.

Greenhouse benches come in almost every form
and design imaginable and unfortunately many
are conducive to creating disease problems. A
well-designed greenhouse bench should feature a
container support base that is independently
supported from bench sides to avoided edges on
which debris may accumulate (fig. 2). The base
should also minimize areas where organic
material can accumulate. The base should be
easily removable for cleaning, decontamination,
and treatment. An ideal system is to use
removable boards impregnated with
cooper-naphthenate . Periodically cleaning and
treating boards achieves an essentially
self-sterilizing base for containers (Baker
1957).

Watering Plants

Plant watering methods are a vital
consideration in disease prevention. To begin
with, containers are commonly overfilled with
growing medium, leaving no reservoir for water.
As a result, excess medium is then flushed from
containers and accumulates under benches to
provide an organic base for microorganisms.
Individual watering nozzles should be hung up

and not allowed to contact the greenhousp floor
where they can become contaminated with
disease-inducing organisms.

Container-grown plants are almost universally
overwatered, which usually leads to seedling
root rot problems. Wildland plants present a
special problem in this regard because of their
innate variability. Wide variation in
germination rate, growth rate, and form
requires selective watering. The
nonselectivity of large automatic watering
systems is a particular problem. Many
desirable western U.S. native plants are
adapted to semiarid environments and grow in
soils with extremely low water potentials
compared to the average domesticated
ornamental. Little literature is available on
the specific soil water potential requirements
of seedlings. The role of soil water potential
and the ecology of plant pathogens have been
studied for some agricultural plant diseases
(Cook and Papendrick 1970). Some unpublished
data on wildland shrubs (Welch and others, USDA
Forest Service, Shrub Sciences Lab., Provo,
Utah), indicate that various species, sagebrush
for example, grown in containers show little
evidence of water stress even at -25 to -30
atmospheres. Visual judgment of the soil
moisture a plant needs will probably result in
overwatering . Critical measurement of soil
moisture requirements is necessary to plan
watering methods and consequently prevent
disease .

Controlling Pathogens in Growing Media

Pathogen-free plant propagules and sanitary
greenhouse management are of no avail without
use of a controlled-pathogen growing medium. A
vital component of native soil is the array of
living microorganisms that exist in a
dynamically fluctuating equilibrium. The
system is controlled by the unique physical,
chemical, and biological environmental
characteristics of specific soil and vegetative
types (Baker 1961; Elton 1958). The system is
biologically buffered and permanent changes
occur only with major environmental shocks.
Such disruptions occur, for example, as a
result of the numerous modifications incident
to agricultural, greenhouse, or nursery
operations .

Containerized plant growing media can be
categorized as either containing soil or as
soilless. The two types require different
treatments to manage pathogens and retain
proper biological and physical plant growth
factors (Baker 1957, 1962a, 1962b). It cannot
be assumed that soilless media ingredients, for
example, peat, sawdust, ground bark, perlite,
or vermiculite are or will remain
pathogen-free. It can be more safely assumed
that what these media do have are low or poorly
balanced microorganism populations. Treatments
to eradicate or control pathogens must contend
with these unique features.

Fumigation of media with chemicals is a
widespread practice, although there are
attending disadvantages (Baker 1957, 1961,
1965). Toxic chemicals are difficult to
contain in greenhouse operations and their use
may become legally complicated in urban areas.
Toxic residues may remain even after long
periods of aeration. Fumigants move through
the soil in a concentration gradient resulting
in nonuniform treatment. Broad spectrum

fumigants such as cloropicrin and methyl
bromide tend to "overkill" and result in
biological vacuums. More specific fungicides,
for example , PCNB, Dexon, carbon disulphide,
and Nemagon are available. However, pathogen
populations are selected for resistance more
rapidly by the more specific chemicals. Steam
sterilization of media by heating to 212° F
also results in biological vacuums. Both
chemical and heat methods have the danger of
recontamination. The drastically reduced
competition in these treated soils results in
rapid uninhibited growth of introduced
pathogenic organisms. Loss to disease may be
more severe than in untreated media.
Phytotoxic compounds are also formed in soils
that are treated at high temperatures.

Aerated-steam treatment of plant growing media
avoids most of these problems (Baker 1962a).
With this system, air is injected into the
steam mass, producing a lower temperature vapor
(fig. 3). By careful adjustment of vapor
temperature, organisms can be selectively
eliminated from the soil. Parasitic organisms
tend to have more specialized enzyme systems
than saprophytic organisms and thus tend to
have lower thermal death points. Most weed
seeds and many pathogenic fungi, bacteria, and
viruses can be eliminated or inactivated in
soil by aerated-steam treatment at 140° F for
30 minutes, leaving a beneficial population of
microorganisms (fig. 4). Remaining fungi,
bacteria, and actinomycetes then increase in
number and antagonistic members act to inhibit
invasion by contaminate pathogens. Fungistatic
soil factors are initially lowered, but return
to normal. Any phytotoxins produced are at low
levels. Fire molds or "weed fungi" that grow
profusely in sterilized soil are suppressed.
The use of aerated steam is less expensive than
steam sterilization because of the reduced
temperature and treatment time required.

MIXING CHAMBER
Steam Supply 3 3 Low TemP Vapo^

•*->

CT3
(/)

c
o

Figure 3. --Diagram illustrating the method of aerated-stream production for heat-treatment of plant
growing media.

100-

90-

80-
70-

■

60-
50-
40-

-200

-780

-760

-740

-720

}

-Resistant weed seed
and viruses

-Most weed seed

-All bacteria and most
viruses

-Soil insects

-Most fungi and bacteria

-Nematodes
- Wate r molds

-700

Figure 4 . --Temperature scale illustrating the
thermal death zones of plant pathogenic fungi,
bacteria, viruses, and other soil organisms and
weed seeds when subjected to moisture and heat,
in most cases for 30 minutes (adapted from
Baker 1957) .

Aerated-steam treatment of soil is a prelude to
and a valuable research tool in achieving
biological control of soil-borne plant
pathogens .

BIOLOGICAL CONTROL OF PLANT PATHOGENS IN
CONTAINER MEDIA

The environment, host plant, and pathogen are
not mutually exclusive. These three elements
interact to result in plant disease. The host
and pathogen are reciprocal biological
environmental elements and also influence and
are influenced by the physical environment.
Cultural methods of managing plant disease are
primarily directed toward manipulating the
physical environment. The host plant,
pathogen, and other biotic elements are the
focus of biological control. The objective of
biological control is not necessarily to
eliminate disease, but to reduce it to a
tolerable level.

Genetic Variability of Plants

Genetic resistance, tolerance, and
susceptibility to pathogens are of fundamental
importance in natural and manipulated
biological control schemes. A basic difference
exists in the genetic nature of wildland plants

and domesticated plants. This is the native,
relatively unaltered genetic variability of
wildland plants. While this characteristic
presents formidable problems for standardized
cultural procedures, it is a virtue in
providing disease resistance that must be
rigidly protected. Variability is a basic
factor in the survival and evolution of plant
species. It must be protected at each step in
the manipulation of native plants to be used
for revegetation or range and wildlife habitat
improvement. Methods used at each step must be
studied carefully for impact on
variability — from seed base selection, seed
collection, seed cleaning, seed storage,
pregermination treatment, and germination
culture to seedling culture and plant
establishment whether it be direct seeding or
planting bare-root or containerized stock. Use
of narrow line, vegetatively produced planting
stock in wildland revegetation projects should
be seriously questioned.

Cultural predisposition of container-grown
plants to various pathogens is a two-fold
problem in disease prevention. There could be
loss from disease in containerized plant
production or the potential for loss extended
in time. If, for example, 50 percent of a
native plant population is susceptible to a
root rot when soil environment tends toward the
anaerobic, one might predict predisposition to
certain pathogens when container-grown plants
are overwatered. The surviving population
could then have a narrowed range of variability
with which to confront their environment when
outplanted .

To take advantage of naturally existing
biological control systems now functioning in
the wildlands of the West, it is important, in
fact imperative, than an extreme effort is made
to return revegetation plants (via
containerized stock, bare-root, or seed) in
near their native genetic state. Systematic
seed collection methods need to be developed
toward maximizing the preservation of the
genetic amplitude of plant populations of
interest. The plague of achieving disease
resistance in agricultural plants has been the
loss of native gene pools through the plant
selection, improvement, and breeding sequence
of domestication. Through history, plant
pathologists and plant breeders have searched
for lost genes by returning to native
populations. Must the native wildland plant
venture repeat the costly mistake of losing
native variability?

Managing Biological Control

Biological control of soil-borne disease
problems centers on manipulating antagonists
and certain physical factors in the growing
medium of container plants. Antagonistic
activity occurs by parasitism, predation,
competition for nutrients, and inhibitions from
metabolic products of another organism (Baker
and Cook 1974) . Disease development may be

suppressed in certain soils even though both
pathogen and susceptible host are present
(Baker and Cook 1974; Liu and Baker 1980).
Both biological and nonbiological factors are
involved in these suppressive soils.
Biological control and the nature of
suppressive soil are at the forefront of
current research on controlling soil-borne
diseases of greenhouse and container-grown
plants (Henis and others 1979; Chet and Baker
1980; Scher and Baker 1980).

With the aerated-steam treatment method already
mentioned, certain pathogens, but not all
pathogens, can be selectively eliminated from
soil. The common spore-forming bacterium
Bacillus subtilis Cohn emend Praznowski is
retained and proliferates, producing rather
specific antibiotics that are antagonistic to
reinvasion by strains of Rhizoctonia solani
Kuhn, a common pathogen of container plants
(Baker and others 1967; Olsen and Baker 1968).
The degree of specificity characteristic of
this bacterium limits broad application.
Strains of the ectomycorrhizal fungus Laccria
accata (Scop.:Fr.) Berk. & Br. protect Douglas
fir (Pseudotsuga menziesii [Mirb.] Franco)
against Fusarium oxysporum Schlect. emend Snyd.
& Hans. , which induces a root rot of seedlings
(Sylvia and Sinclair 1983) . The disease is
suppressed in soil-free systems but not in
heat-treated soil. Seedling root growth,
however, is also suppressed by cell-free
metabolites of the fungus. Various soil-free
formulations containing composted hardwood bark
used as a growing medium are suppressive to
Phy tophthora c immamomi Rands, Rhizoctonia
solani , and Fusarium oxysproum, respectively

root rot, damping-off, and wilt inducers
(Hoitink and others 1977; Nelson and Hoitink
1983; Chef and others 1983). A dual mechanism
has been suggested, attributed to antagonistic
fungi (for example, Trichoderma harzianum
Rifai) and heat-stable chemical inhibitors.
Modification of soil factors such as pH and
moisture levels can induce suppressiveness in a
conducive soil. Parasitism of Rhizoctonia by
Trichoderma is enhanced with these
modifications .

Container growing media containing native soils
have the advantage of a more diverse, complex
microbiota than soilless artificial media.
With complexity comes stability and a greater
chance of biological control without
modifications based on extensive research.
With introduction of specific antagonistic
fungi into sterile or soilless media to
suppress specific pathogens there remains the
risk of contamination and introduction of a
second pathogen not influenced by the existing
antagonists. In addition, the medium
environment must be adapted to the selected
antagonist. The potential for developing
biological control with container-grown
wildland plant diseases must exist. Existing
natural systems must be studied. Disease
inducing organisms and specific antagonists
need to be identified.

One must conclude that no single disease
control method is a complete answer, and so we
hear terms like integrated control or a
holistic approach — the battle goes on.
Regardless and undoubtedly, sanitation and good
housekeeping will continue to be in order.

PUBLICATIONS CITED

Baker, K. F. Development and production of
pathogen-free seed of three ornamental
plants. Plant Dis. Rep. Suppl. 238: 68-71;
1956.

Baker, K. F. ed. The U. C. system for producing
healthy container grown plants. Manual 23.
Berkeley, CA: University of California, Calif.
Agr. Exp. Sta.; 1957. 332 p.

Baker, K. F. Control of root-rot diseases;
section 5, the pathogenesis of root
degeneration. In: Toronto: University of
Toronto Press; Recent Advances in Botany 1:
486-490; 1961.

Baker, K. F. Principles of heat treatment of
soil and planting material. J. Austr. Inst.
Agric. Sci. 28: 118-126; 1962a.

Baker, K. F. Thermotherapy of planting
material. Phytopathology. 52: 1244-1255;
1962b.

Baker, K. F. Disease-free plants. In:

Symposium, a look into the future; 1965
October 26 and 27. Dedication of the Kenneth
Post Laboratories, New York State Flower
Growers, Inc., and Cornell University; The
Kenneth Post Foundation; 1965. 9 p.

Baker, K. F. Aerated-steam treatment of seed
for disease control. Hort. Res. 9: 59-73;
1969.

Baker, K. F. Seed pathology. In: Kozlowski, T.
T. , ed. Seed biology. Vol. 2. New York:
Academic Press; 1972: 317-416.

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

Baker, K. F. ; Flentje, N. T. ; Olsen, C. M. ;
Stretton, H. M. Effect of antagonists on
growth and survival of Rhizoctonia solani in
soil. Phytopathology. 57: 591-597; 1967.

Baker, K. F.; Smith, S. H. Dynamics of seed
transmission of plant pathogens. Annu. Rev.
Phytopathol. 4: 311-334; 1966.

Chef, D. G. ; Hoitink, H. A. J.; Madden, L. V.
Effects of organic components in container
media on suppression of Fusarium wilt of
chrysanthemum and flax. Phytopathology. 73:
279-281; 1983.

Chet, I.; Baker, R. Induction of

suppressiveness to Rhizoctonia solani in
soil. Phytopathology. 70: 994-998; 1980.

Cook, R. J.; Papendrick, R. I. Soil water
potential as a factor in the ecology of
Fusarium roseum f. sp . cerealis "Culmorum".
Plant and Soil. 32: 131-145; 1970.

Elton, C. S. The ecology of invasions by

animals and plants. New York: John Wiley and
Sons; 1958. 181 p.

Harman, G. E. Mechanisms of seed infection and
pathogensis. In: Symposium on deterioration
mechanisms in seed; 73d annual meeting of the
American Phy topathological Society; 1981
August 3; New Orleans, LA. Phytopathology.
73: 326-329; 1983.

Henis, Y. ; Ghaffer, A.; Baker, R. Factors
affecting suppressiveness to Rhizoctonia
solani in soil. Phytopathology. 69: 1164;
1979.

Hoitink, H. A. J.; VanDoren, D. M. ;
Schmitthenner , A. F. Suppression of
Phy tophthora cinnamomi in a composted
hardwood bark potting medium. Phytopathology.
67: 561-565; 1977.

Liu, S. ; Baker, R. Mechanism of biological
control in soil suppressive to Rhizoctonia
solani. Phytopathology. 70: 404-412; 1980.

Nelson, E. B. , Hoitink, H. A. J. The role or
microorganisms in the suppression of
Rhizoctonia solani in container media amended
with composted hardwood bark. Phytopathology.
73: 274-278; 1983.

Olsen, C. M. ; Baker, K. F. Selective heat
treatment of soil, and its effect on the
inhibition of Rhizoctonia solani by Bacillus
subtilis. Phytopathology. 58: 79-87; 1968.

Scher, F. M. ; Baker, R. Mechanism of biological
control in a Fusarium-suppressive soil.
Phytopathology. 70: 412-417; 1980.

Sylvia, D. M. ; Sinclair, W. A. Suppressive
influence of Laccaria laccata on Fusarium
oxyporum and on Douglas-fir seedlings.
Phytopathology. 73: 384-389; 1983.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT- 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

BIOLOGY AND MANAGEMENT
Robert L.

ABSTRACT

Botrytis cinerea is an important pathogen of coni-
fer seedlings in western North America, especially
within greenhouses. Environmental conditions in
greenhouses, such as high humidity and cool temper-
atures, are conducive to infection by and spread of
this fungus. To reduce losses from Botrytis blight,
cultural practices aimed at reducing inoculum and
altering environmental conditions necessary for
infection should be combined with rotated use of
different fungicides. Several fungicides used to
control Botrytis in the past are no longer effec-
tive because the fungus has developed tolerance to
them. Fungicides commonly used to control this
disease are discussed.

INTRODUCTION

Grey mold caused by Botrytis cinerea (Fr.) Pers.
is one of the most damaging diseases of seedlings
in forest tree nurseries. The disease is espe-
cially severe on containerized conifers in green-
houses where conditions are ideal for infection by
and buildup of the fungus (James, Woo and Myers
1982; McCain 1978). However, Botrytis blight may
also occur in seedbeds where it causes damage
during cool, wet port ions of the year (James 1980;
James and others 1983). The fungus is also
responsible for losses to seedlings in storage
(Smith and others 1973) .

Although many conifer species are susceptible to
Botrytis , greatest damage has been reported on
Douglas-fir, western hemlock, lodgepole pine, and
spruce in British Columbia (Sutherland and Van
Eerden 1980), western larch, lodgepole pine, and
Engelmann spruce in northern Idaho and northwestern
Montana (James and Genz 1983; James and Gilligan
1983; James and others 1982), lodgepole pine,
Scots pine, Engelmann spruce and blue spruce in
Colorado (Gillman and James 1980), and giant
sequoia and Douglas-fir in California (McCain and
Smith 1978) .

BIOLOGY

Of the 22 species of Botrytis , B_. cinerea, the one
that affects conifer seedlings, is the most common
and has the widest host range (over 200 plant
species) (Jarvis 1980b; Sutherland and Van Eerden
1980) . Other Botrytis species are more pathogen-
ically specialized and thus have narrower host
ranges .

Robert L. James, Plant Pathologist, Cooperative
Forestry and Pest Management, Northern Region,
USDA Forest Service, Missoula, Montana.

OF BOTRYTIS BLIGHT
James

A typical disease cycle for B. cinerea is
shown in figure 1. Initial infection in
nurseries results from spores produced on nearby
infected plants or crop debris and from fungal
resting structures (sclerotia) (Coley-Smith 1980;
McCain 1978). Sclerotia often form after the
growth phase of the fungus or following seedling
mortality (Coley-Smith 1980) . These sclerotia
persist in soil, plant debris or within green-
houses and can produce both sexual (ascospores)
and asexual (conidia) spores.

The sexual stage of the fungus is Botryotinia
f uckeliana (DeBary) Whetzel, which has been
found frequently in nature (Jarvis 1980b) .
Apothecia produced from overwintering sclerotia
give rise to ascospores which may initiate in-
fection (Jarvis 1980a). However, asexual conidia
are responsible for most infection, spread, and
buildup of the disease in nurseries.

Figure 1. — Disease cycle of Botrytis cinerea
(after Jarvis 1980a) .

Conidia are dry and usually dispersed by air
currents and less frequently carried by water
droplets (Jarvis 1980a) . Conidial dispersal
occurs primarily when the relative humidity is
rising or falling rapidly (Jarvis 1980a) . Presence
of free moisture on foliage for several hours and
prolonged cool temperatures of about 13-14° C are
necessary for infection (Blakeman 1980) . Germi-
nating conidia form appressoria on the surface of
leaves and germ tubes penetrate directly through
the cuticle (Blakeman 1980) . Wounded or necrotic

host tissues are quickly infected and colonized
(Sutherland and Van Eerden 1980).

Within the disease cycle, the fungus may become
inactive (latent) following conidial dispersal
or infection (figure 1) . However, when inoculum
is abundant and environmental and host suscep-
tibility conditions are conducive, "aggressive
pathogenicity" occurs (Jarvis 1980a) . Conducive
environmental conditions include high relative
humidity, cool temperatures, and free surface
moisture on foliage. Host susceptiblity factors
include nutrient imbalances causing seedling stress
and presence of senescent tissues for saprophytic
buildup of inoculum (Sutherland and Van Eerden
1980) . When conditions for infection are ideal
and inoculum abundant, latent periods are short
and epidemics can occur quickly (Jarvis 1980a) .

Symptoms of Botrytis infection usually become
apparent when crowns of conifer seedlings begin
to close and affected seedlings usually occur in
isolated pockets (Gillman and James 1980; James
and others 1982). The fungus usually first
attacks senescent tissues at the base of seedlings
and then spreads to surrounding live host material
(Smith and others 1973; Sutherland and Van Eerden
1980) . Symptoms on infected seedlings include
needle necrosis, twig and stem lesions, and
mortality.

MANAGEMENT

Controlling Botrytis blight is difficult because
the pathogen is capable of attacking all plant
parts at almost any stage of their growth and in
storage (Maude 1980) . The best approach to control
is to avoid conditions that are suited for disease
buildup. This includes controlling stocking by
reducing density to improve air circulation among
seedlings (Cooley 1981), which means producing
fewer trees per unit area. However, this is com-
pensated by higher quality, disease-free seedlings.
If possible, irrigation during periods of host sus-
ceptibility should also be limited (Cooley 1981).
Adding drying agents to irrigation water to expedite
drying of foliage may also help reduce infection.
Fertilization should also be done properly. For
example, too much fertilizer may cause seedlings
to burn, providing ideal infection courts for
Botrytis (Sutherland and Van Eerden 1980), and too
little fertilizer may stress seedlings making them
more susceptible to infection (Cooley 1981).
Another important cultural practice to reduce loss
from Botrytis blight is sanitation, aimed primarily
at reducing inoculum. Sanitation practices include
periodic removal of infected plants and plant
debris, and cleaning greenhouse benches and floors
with a surface sterilant between crops (Cooley
1981). Potential inoculum sources outside green-
houses, especially those upwind, should be elimin-
ated when possible.

As containerized production of conifers has in-
creased, Botrytis blight has become more important.
As a result, many growers have had to rely on fungi-
cides to keep losses at acceptable levels. Several
fungicides either used operationally or showing
promise for future use are listed in table 1. Some

of the more important of these are discussed below.

Benomyl is a systemic fungicide that has been
used operationally since the early 1970' s. When
it was first introduced, benomyl provided excellent
control of many diseases over a wide range of crop
plants. As a result, many growers began to use
it exclusively to control Botrytis blight, espe-
cially in greenhouses (McCain 1978; Miller and
Fletcher 1974). However, as early as 1971 toler-
ance to benomyl by Botry t is was evident (Bollen
and Scholten 1971) . Since then, there have been
many reports of tolerance to this fungicide by
different pathogens on a variety of crops including
ornamental flowers, vegetables, fruit crops, and
conifer seedlings (Cooley 1981; Gillman and James
1980; James and Gilligan 1983; Jarvis and
Hargreaves 1973; Miller and Fletcher 1974). Simple
tests have been developed to quickly assay presence
of tolerant fungal strains. These involve growing
the test organisms on nutrient media amended with
the fungicide. Such tests have been used to
evalute tolerance of Botrytis strains to benomyl
and other fungicides throughout the West. Results
indicate that tolerance of Botrytis to benomyl is
so widespread that this chemical is usually
ineffective and no longer recommended for use in
most nurseries (Cooley 1981; Gillman and James
1980; James and Gilligan 1983).

Chlorothalonil is another fungicide that has been
commonly used to control Botrytis in greenhouses.
However, its ability to adequately control the
disease has often been reduced, especially after
continued use (James and Gilligan 1983) . Recent
tests indicate that some Botrytis populations in
Oregon, Montana, and Colorado are tolerant to
chlorothalonil (Cooley 1981; Gillman and James
1980; James and Gilligan 1983). Although tolerance
to chlorothalonil is not as widespread as with
benomyl, it is fairly common and has been shown to
develop quickly in greenhouses (James and Gilligan
1983) .

Captan is a general protective fungicide that is
fairly effective against Botrytis (James and others
1982). However, tolerant strains to this fungicide
have also been shown to exist (Cooley 1981;
Gillman and James 1980; James and Gilligan 1983;
Parry and Wood 1959) .

Dicloran is an effective fungicide against Botrytis
diseases (James and others 1982) , even though
tolerance of natural Botrytis strains has been
found (Cooley 1981; Gillman and James 1980; James
and Gilligan 1983; Webster and others 1970). Toler-
ant strains of the fungus can also easily develop
in the laboratory (James, unpublished). Therefore,
dicloran should not be used repeatedly unless
rotated with other fungicides.

Two relatively new fungicides should also be
mentioned. Iprodione was originally developed for
turf diseases (Danneberger and Vargas 1982; Sanders
and others 1978) and shows strong toxicity
towards Botrytis (Pappas and Fisher 1979; Powell
1982). Vinclozolin is a chemical with specific
action against Botrytis and related fungi (Pappas
and Fisher 1979; Ritchie 1982). Iprodione has

been tested against Botrytis blight of conifers
and shows excellent promise (James and others 1982) .
Vinclozolin was also tested, but showed extensive
phytotoxicity to western larch seedlings at label
rates (James and Genz 1983) . Both fungicides
require more field tests and need to be registered
for use on conifers. Previous tests (Cooley 1981;
James and Gilligan 1983; Leroux and others 1977;
Pappas and others 1979) indicate that strains of
Botrytis tolerant to ipriodione and vinclozolin
exists, although not in large numbers. Tolerant
strains can also develop rapidly to these fungi-
cides in the laboratory (James, unpublished).

Apparently none of the fungicides currently avail-
able can be considered completely effective
against all Botrytis strains likely to be encoun-
tered. As a result, fungicide useage should be

limited to the minimum amounts necessary for
effective disease control. Also, different fungi-
cides should be used in rotation so as not to
exert selective pressure on Botrytis populations
to develop tolerance. Rotated fungicides should
have different modes of action, i.e. systemic
chemicals alternated with broad spectrum protect-
ants (Cooley 1981; James and Gilligan 1983).

For effective control of Botrytis blight, cultural
practices, such as better sanitation, providing
adequate air circulation, and reducing irrigation,
should be combined with rotated use of different
fungicides. Cultural practices can reduce fungal
inoculum and alter environmental conditions
necessary for infection, whereas fungicides can
protect susceptible plant tissues from infection.
The combination of both procedures is necessary
for an effective control strategy.

Table 1. — Fungicides used to control Botrytis blight in containerized conifer nurseries.

Fungicide

Trade names

Manuf ac t ur er s

Chemical name

benomyl

Benlate®
Tersan 1991®
Benomyl

Dupont

Lilly Miller

Methyl-1- (butylcarbamoyl) -2 benzimidazole carbamate

captan

Captan

Or thoc ide®

Stauf f er
rhpvron

N-[ (Trichloromethyl) thio ]-4-cyclohexene-l ,

7 — c\ i pa rhoximi dp

chlorothalonil

Bravo 500®
Daconil 2787®

Diamond Shamrock

Tetrachloroisophthalonitrile

copper

Tri-Basic®

CP Chemical
Phelps-Dodge
Cities Service

Basic copper sulfate

dicloran

Bo t ran®

Tuco

2, 6-Dichloro-4-nitroaniline

f erbam

Carbamate

Dupont

ferric dimethyldithiocarbmate

iprodione

Chipco 26019®
Rovral®

Rhone-Poulenc

3 (3, 5-dichlorophenyl)-N-(l-methylethyl)-2,4-dioxo-l-
imidazolidinecarboximide

mancozeb

Fore®

Dupont

Contains 16% maganese, 2% zinc and 62% ethylenebisdithio-
carbamate ion/maganese ethylenebisdithiocarbamate plus
zinc ion.

maneb

Dithane M-45®

Rhom & Haas

maganese ethylene bisdithiocarbamate

thiophanate-
methyl

Zyban®

Mallinckrodt

dimethyl[ (1, 2-phenylene)bis (iminocarbonothyioyl) ]bis
(carbamate)

thiram

Thylate®

Dupont

Tetramethylthiuram disulfide

vinclozolin

Ronilan®
Ornalin®

BASF

Mallinckrodt

3- (3, 5-dichlorophenyl)-5-ethenyl-5-methyl-2, 4-
oxazolidinedione

zineb

Zineb

Dithane 278®

Rhom & Haas

zinc ethylenebisdithio-carbamate

PUBLICATIONS CITED

Blakeman, J. P. Behaviour of conidia on aerial
plant surface. In: Coley-Smith, J. R. ;
Verhoeff, K. ; Jarvis, W. R. , eds. The biology
of Botrytis . London: Academic Press; 1980:
115-151.

Bollen, G. J. ; Scholten, G. Acquired resistance
to benomyl and some other systemic fungicides
in a strain of Botrytis cinerea in cyclamen.
Neth. J. PI. Path. 77: 80-90. 1971.

Coley-Smith, J.R. Sclerotia and other structures
of survival. In: Coley-Smith, J. R. ; Verhoeff,
K. ; Jarvis, W. R. , eds. The biology of
Botrytis . London: Academic Press; 1980: 85-114.

Cooley, S. J. Fungicide tolerance of Botrytis
cinerea isolates from conifer seedlings.
Portland, OR: U.S. Department of Agriculture,
Forest Service, Pacific Northwest Region; 1981.
13 pp.

Danneberger, T. K. ; Vargas, J. M. , Jr. Systemic
activity of iprodione in Poa annua and post-
infection activity for Drechslera sorokiniana
leaf spot management. Plant Disease 66(10):
914-915. 1982.

Gillman, L. S.; James, R. L. Fungicidal toler-
ance of Botrytis within Colorado greenhouses.
Tree Planters' Notes 31(1): 25-28. 1980.

James, R. L. Engelmann spruce needle blight at
the Coeur d'Alene nursery, Idaho. Rept. 80-21.
Missoula, MT: U. S. Department of Agriculture,
Forest Service, Northern Region; 1980. 5 pp.

James, R. L. ; Genz, D. Fungicide tests to con-
trol Botrytis blight of containerized western
larch at the Champion Timberlands Nursery,
Plains, Montana. Rept. 83-12. Missoula, MT:
U. S. Department of Agriculture, Forest Service,
Northern Region; 1983. 7 pp.

James, R. L. ; Gilligan, C. J. Fungicidal toler-
ance of Botrytis cinerea from the Flathead
Indian Reservation greenhouse, Ronan, Montana.
Rept. 83-5. Missoula, MT: U. S. Department
of Agriculture, Forest Service, Northern Region;
1983. 15 pp.

James, R. L. ; Woo, J. Y.; Malone, P. Evaluation
of fungicides to control Botrytis blight in
western larch seedbeds at the Coeur d'Alene
nursery, Idaho. Rept. 83-6. Missoula, MT:
U. S. Department of Agriculture, Forest Service,
Northern Region; 1983. 8 pp.

James, R. L.; Woo, J. Y.; Myers, J. F. Evaluation
of fungicides to control Botrytis blight of con-
tainerized western larch and lodgepole pine at
the Coeur d'Alene nursery, Idaho. Rept. 82-17.
Missoula, MT: U. S. Department of Agriculture,
Forest Service, Northern Region; 1982. 13 pp.

Jarvis, W. R. Epidemiology. In: Cole>-Smith,
J. R.; Verhoeff, K. ; Jarvis, W. R., eds. The
biology of Botrytis . London: Academic Press;
1980a: 219-250.

Jarvis, W. R. Taxonomy. In: Coley-Smith, J. R.;
Verhoeff, K. ; Jarvis, W. R. , eds. The biology
of Botrytis . London: Academic Press; 1980b:
1-18.

Jarvis, W. R. ; Hargreaves, A. J. Tolerance to
benomyl in Botrytis cinerea and Penicillium
corymbif erum. Plant Pathology 22: 139-141.
1973.

Leroux, P.; Fritz, R.; Gredt, M. Etudes en
laboratoire de souches de Botrytis cinerea
Pers., resistantes a la dichlozoline , au
dichloran, au qunitozene, a la vinchlozoline et
au 26019 RP (ou Glycophene) . Phytopathol. Z.
89: 347-348. 1977.

Maude, R. B. Disease control. In: Coley-Smith,
J. R. ; Verhoeff, K. ; Jarvis, W. R. , eds. The
biology of Botrytis . London: Academic Press;
1980: 275-308.

McCain, A. H. Nursery disease problems -

containerized nurseries. In: Gustafson, R. W.,
ed . Western forest nursery council and Inter-
mountain Nurseryman's Association: conference
and workshop proceedings; Eureka, CA; 1978:
B139-142.

McCain, A. H.; Smith, P. C. Evaluation of fungi-
cides for control of Botrytis blight of
container-grown redwood seedings. Tree Planters
Notes 29(4) : 12-13. 1978.

Miller, M. W.; Fletcher, J. T. Benomyl tolerance
in Botrytis cinerea isolates from glasshouse
crops. Trans. Br. Mycol. Soc . 62(1): 99-103.
1974.

Pappas, A. C. ; Cooke, B. K. ; Jordan, V. W. L.
Insensitivity of Botrytis cinerea to iprodione,
procymidone and vinclozolin and their uptake by
the fungus. Plant Pathology 28(1): 71-76. 1979

Pappas, A. C; Fisher, D. J. A comparison of the
mechanisms of actions of vinclozolon, procymi-
done, iprodione and prochloraz against Botrytis
cinerea . Pesticide Science 10: 239-246. 1979.

Parry, K. E. ; Wood, R. K. S. The adaptation of
fungi to fungicides: adaptation to captan. Ann.
Appl. Biology 47(1): 1-9. 1959.

Powell, C. C. New chemicals for managing disease
on glasshouse ornamentals. Plant Disease
66(2): 171. 1982.

Ritchie, D. F. Effect of dicloran, iprodione,
procymidone, and vinclozolin on the mycelia
growth, sporulation, and isolation of resistant
strains of Monilinia f ructicola. Plant Disease
66(6): 484-486. 1982.

Sanders, P. L. ; 3urpee, L. L; Cole, H., Jr.;
Duich, J. M. Control of fungal pathogens of
turf grass with the experimental iprodione
fungicide, R. P. 26019. Plant Dis. Reptr.
62(6): 549-553. 1978.

Smith, R. S., Jr.; McCain, A. H. ; Srago, M. D.
Control of Botrytis storage rot of giant
sequoia seedlings. Plant Dis. Reptr. 57(1):
67-69. 1973.

Sutherland, J. R. ; E. Van Eerden. Diseases and
insect pests in British Columbia forest
nurseries. Joint Rept. No. 12. British
Columbia Ministry of Forests, Canadian Forestry
Service; 1980. 55 pp.

Webster, R. K. ; Ogawa, J. M. ; Bose, E. Tolerance
of Botrytis cinerea to 2, 6-Dichloro-4-nitro-
aniline. Phytopathology 60(10): 1489-1492.
1970.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT-168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

SALT TOLERANCE OF 10 DECIDUOUS SHRUB AND TREE SPECIES

Richard W. Tinus

ABSTRACT: Ten species of deciduous shrubs and
trees were grown in a greenhouse and irrigated
with nutrient solution plus sodium sulfate,
chloride, and bicarbonate to yield salt concen-
trations with conductivity of 1.6, 4.5, 7.2, 12.1,
and 16.6 mmhos/cm. Honeysuckle, crabapple, lilac,
and American plum were salt sensitive. Buffalo-
berry, Russian olive, and chokecherry were moder-
ately sensitive. Green ash, juneberry, and
caragana were tolerant.

INTRODUCTION

Tree nurseries in western North America frequently
have salt-affected soils and salty irrigation
water (Tinus 1980) . Salt creates an osmotic
moisture stress that reduces germination and
growth, and may kill seedlings. Without careful
soil and water management, the problem gradually
becomes worse until the nursery is no longer able
to grow certain species that it formerly grew
well. In the West, because shelterbelts are
commonly planted on salty soils, careful choice of
species is critical.

Very little quantitative information is available
on salt tolerance of shrubs and trees grown for
shelterbelts (Carter 1980; 1979). Most of what is
available is on crop plants (Richards 1954;
Branson 1978: Maas and Hoffman 1977; Rathert and
Doering 1981) and horticultural varieties of
shrubs and fruit trees (Bernstein and others 1972;
Dirr 1974; Francois and Clark 1978; Maas and
Hoffman 1977; Townsend 1980; Pasternak and Forti
1980). The objective of this study was to provide
guidelines on salt tolerance of a variety of
species commonly used for shelterbelts in the
northern and central Great Plains.

METHODS AND MATERIALS
Experiment 1. — Seed Germination

Green ash seed was soaked 4 days in cold running
water, caragana was used dry, and all other
species were cold stratified in sand as recom-
mended by Schopmeyer (1974) .

Richard W. Tinus is Research Plant Physiologist at
the Rocky Mountain Forest and Range Experiment
Station, USDA Forest Service, Forestry Sciences
Laboratory, Flagstaff, Ariz., in cooperation with
Northern Arizona University.

Seed x^as germinated in petri dishes containing
filter paper, 100 seed per dish, five dishes per
species. Each of the five dishes per species was
moistened with one of the nutrient solutions plus
sodium chloride, sulfate, and bicarbonate listed
in table 1 .

The dishes were covered, enclosed in plastic bags
to retard evaporation, and placed in a germinator
with a 12-hour day (fluorescent light) at 30° C
and a 12-hour night at 20 C. Humidity ranged
from 60 to 100 percent.

Germinants were counted and removed every few
days, and moisture was replenished as needed with
distilled water. The experiment was terminated
after 45 days. Total germination and germination
energy (average percent per day to 50 percent of
maximum germination) were calculated. Significant
differences between salt levels within species
were determined by Goodman's (1964) test.

Experiment 2. — Seedling Growth

Fifty Colorado State styroblocks, each with 30
cavities with a volume of 400 ml per cavity, were
filled with 1:1 peat-vermiculite plus 5 percent
forest duff to inoculate with endomycorrhizal
fungi. Three seeds were planted in each cavity,
five blocks for each of the 10 species. The
blocks were arranged on greenhouse benches in
randomized groups of 10, one block of each species.
Each group was watered as needed with a nutrient
solution plus sodium sulfate, chloride, and
bicarbonate calculated to have an electrical
conductivity (EC) of 1.6, 4.5, 7.2, 12.1, and 16.6
mmhos/cm (table 1). The soil salinity of the
Lincoln-Oakes Nurseries at Bismark, N.D. (table 1)
corresponds approximately to solution #2. The
relative proportions of sodium sulfate, chloride,
and bicarbonate were selected to be the same as in
the irrigation water of Lincoln-Oakes, which has
EC of 1,500 mmhos (about 1,000 ppm solids) and is
rated "suitable for limited irrigation." Water
supplies of other nurseries vary in composition
considerably, but these ions are usually the ones
causing the greatest problems.

After germination, the seedlings were thinned to
one per cavity, leaving the largest. The remain-
ing seedlings were allowed to grow 14 weeks.
After this time, some of them were as large as
they could be in the container without appreciable
growth restriction, and differences between seed-
lings watered with different salt concentrations
were clearly evident. The blocks of seedlings

Table 1. — Composition of nutrient and salt solutions in parts per million

Solution number

Component 12 3 4 5

EC (mmhos/cm) . 1.6 4.5 7.2 12.1 16.6

N as N03~ 229 224 220 211 202

N as NH.+ 67 66 64 62 59

P as H2P0 ~ 27 27 26 25 24

K+ 155 152 149 143 136

S as SO ~ 142 139 136 131 125

Ca"*"4" 212 208 204 195 187

Mg"1"1" 48 47 46 44 42

Fe 4 4 4 4 4

B as H3B03 0.5 0.5 0.5 0.5 0.5

Mn++ 0.5 0.5 0.5 0.5 0.5

ZN^ 0.05 0.05 0.05 0.05 0.05

CU 0.02 0.02 0.02 0.02 0.02

Mo as Mo0~ 0.01 0.01 0.01 0.01 0.01
4

Na+ 0 786 1,572 3,144 4,716

Cl~ 4 105 210 420 630

S04= 0 922 1,844 3,688 5,532

HC03~ 0 732 1,464 2,928 4,392

TOTAL 889 3,416 5,943 10,998 16,052

were photographed and survivors were counted.
Stem height and the length of two fully mature
leaves were measured on each seedling.

For each species and measurement, a regression
equation was calculated with height, leaf length,
or survival as a function of salt concentration
(measured by EC) . Eight equation forms were tried
using the Hewlett-Packard 9825A family regression
program (General Statistics Vol. I^tape 09825-
15004). The one with the highest r was used to
calculate the salt concentration at which growth
or survival was reduced by 25 percent compared to
growth or survival with nutrient solution only.

RESULTS AND DISCUSSION
Experiment 1. — Seed Germination

Russian olive and caragana germinated well at all
salt concentrations, and neither total germination
nor germination energy declined noticeably at high
salt concentrations (table 2) . Germination energy
of buffaloberry declined steadily with increasing
salt concentration, but total germination remained
high through 12.1 mmhos/cm. Total germination of
green ash and honeysuckle declined somewhat, and
germination energy was greatly reduced by high
salt concentration. Total germination and

,_j

\-t

■ 1

—>

rrt

p
P

M-l

U_J

rJ— '

V-i

, |

I |

rrt

r-l

i — i

4—1

(— 1
i-i

4-J

i—i

r-
(-J

tJ—

4-J

r-l

•H

1 1

f—

•H

tl
M

r-<

t-i

r | |

1 )

(-»
M

4-J

r-t

r«

cu*

•H

r-l

4-J

, |

r-<

■H

r«

1— M

►>
k>

r-\
uj

1 1 |

1 |

r-l

C/j

r1
V-i

i — !

rrt

r-t

4—)

I— t

f"V

t— M

r-i

.J— <

rrt

^— >

cr)

i-i

rrt

p
P

r\
UJ

S-J

fjJj

""J

>r_j

i-Cj

1 1

r-*

i
I

rrt

i — I

S-i

c
o

•H
4-)

•H

to
o

4-1

•H

>
■rl

4-1

c
o

•H

co
o
J3

o
3

C
O
CJ

C3
O

O
cn

co
cu

•H

o
cu

. — i

-<J-

LP)

LT)

1
1

(Ti

i — i

F— 1

CX3

C*0

4-1

S-i

<r->

i—i

1
1

i—i

CT>

I—I

I— 1

■ — i

1 — 1

T3
CTi

-P

£3
CU
O

CJ
CN

CN
CM

O
co

CO
CO

CTi

m
oo

00
00

CM
00

o
o

O-N

S-i

S-4

S-i

P-i

•r-l

•rl

cfl

•rl

•H

■H

!-i

S-)

S-i

4-1

S-i

4-1

■rl

S-i

•rl

cu cd

S-i

CX CO

•H

6£

•H

ct) 3

•H

><!

■rl

S-i

43 i — 1

S-i

I—I

cJ cC

S-i

<4-4

•rl

C/i

S^ S

S-i

v — '

CJ w

Table 3. — Salt concentration (measured by conductivity) causing a 25 percent reduction
in growth or survival, compared to nutrient solution with EC of 1.6 mmhos/cm

Regression quality (r )

Species Height Leaf Percent Height Leaf Percent

length survival length survival

Honeysuckle

(Lonicera tatar ica L . )

Crabapple

(Malus baccata (L.) Borkh.)
Lilac

(Syringa vulgaris L . )

American plum

(Prunus americana Marsh. )

- - - - mmho s / cm - - - -

2.2 3.3 3.3

2.6 6.0 — 1

3.6 4.1 15.7

6.3 7.1 5.0

.55 .32 .71

.54 .67 NS

.70 .71 .92

.35 .78 .69

Buf f aloberry
(Shepherdia argentea
(Pursh) Nutt.)

Russian olive

(Eleagnus angustif olia L . )

Chokecherry

(Prunus virginiana L . )

Green ash

(Fraxinus pennsylvanica
Marsh.)

7.6 8.2 >16.6

8.3 >16.6 >16.6

8.7 9.6 >16.6
11.7 8.6 >16.6

.33 .29 .33

.30 .18 NS

.30 .60 NS

.42 .30 NS

Juneberry 11.8 14.5 >16.6 .51 .36 NS

(Amelanchier alnif olia
(Nutt) Nutt.)

Caragana >16.6 5.1 >16.6 .07 .23 NS

(Caragana arborescens Lam . )

Regression equation not meaningful.

germination energy of crabapple and lilac declined
precipitously with the first increment of salt,
and germination was almost nil at 16.6 mmhos/cm.

Experiment 2. — Seedling Growth

Table 3 lists the 10 species tested in order of
increasing salt tolerance as measured by height
growth. As expected, leaf length was reduced by
about the same degree as stem height (Sepaskhah
and Boersma 1979), except that leaf length re-
sponse of Russian olive was more nearly in keeping
with field observation than height response.
Russian olive has a reputation for being highly
salt tolerant. Bernstein and others (1972) report
that the salt tolerance of a related species,
silverberry (Eleagnus pungens) , is also high; the
threshhold for reduction of growth in silverberry
is 9.4 mmhos/cm. Caragana also showed high salt
tolerance when measured by height reduction, but
not when measured by leaf length. It is possible
that reduced leaf length is part of the species'

adaptive reaction to moisture stress. This agrees
with field observations because caragana flowers
and grows vigorously in early summer, when moisture
is normally adequate, but yellows and begins
dropping its leaves in August, when moisture
stress is frequently high.

As with germination, height growth and leaf length
of honeysuckle, crabapple, and lilac decreased
rapidly with increasing salt. Maas and Hoffman
(1977) also report that apple (Malus sylvestris L.
Mill) is salt sensitive. American plum was sensi-
tive, as expected, in comparison with Prunus
domestica (Richards 1954; Maas and Hoffman 1977) ,
but chokecherry (Prunus virginiana L.) was sur-
prisingly tolerant, especially with respect to
survival .

Once established, most species survived well at
much higher salt concentrations than were required
to suppress growth. Exceptions were honeysuckle
and American plum. Survival information is thus
useful to tree planters for site selection, but

SALT TOLE

HHHHHHI^BHi

SALT TQLERJ*^-

Figure 1. — Decreasing growth with increasing salt concentration
(measured by EC) of (A) lilac, a salt sensitive species and (B)
Russian olive, a salt tolerant species.

not to nurserymen, whose product must reach a
certain size within one or two growing seasons.

Because of the need to keep this experiment small
and simple, only one germinating dish of 100 seed
and only one block of 30 seedlings per species per
treatment was used. For statistical purposes, the
individual seed or seedling was treated as the
unit of replication. Strictly speaking, however,
there was no replication. Furthermore, variability
was great, and the regression equations used
yielded confidence limits so great that only the
broadest comparisons between species can be made.
Thus, although the results were quite obvious even
without measurement (fig. 1), they should be
considered indicative and not definitive.

CONCLUSIONS AND RECOMMENDATIONS

1. Crabapple, lilac, American plum, and honey-
suckle are sensitive to salt. They should
not be grown at a nursery with salty irriga-
tion water or soil nor outplanted into salty
soils .

2. Buf f aloberry , Russian olive, chokecherry,
green ash, juneberry, and caragana are salt
tolerant. Their growth should not be limited
at most western nurseries because of salt
problems, and they should be able to tolerate
the saltiness of most western soils where
shelterbelts are planted.

PUBLICATIONS CITED

Bernstein, L. ; Francois, L. E. ; Clark, R. A.
Salt tolerance of ornamental shrubs and ground
covers. J. Am. Soc. Hortic. Sci. 97(4): 550-
556; 1972.

Branson, R. L. Soluble salts, exchangeable
sodium, and boron in soils. In: Reisenauer,
ed . Soil and plant tissue testing in Califor-
nia; University of California, Division of
Agricultural Science Bull. 1879: 42-45; 1978.

Carter, M. R. Iron chlorosis of Colorado spruce
and Scots pine. In: Indian Head Nursery 1979
annual report, Prairie Farms Rehabilitation
Administration, Indian Head, Saskatchewan;
1979: 35.

Carter, M. R. Effects of sulfate and chloride
soil salinity on growth and needle composition
of Siberian larch. Can. J. Plant Sci. 60: 903-
910; 1980.

Schopmeyer, C. S., technical coordinator. Seeds
of woody plants in the United States. Agric.
Handb. 450. Washington, DC: U.S. Department of
Agriculture; 1974. 883 p.

Sepaskhah, A. R. ; Boersma, L. Elongation of
wheat leaves exposed to several levels of
matric potential and NaCl-induced osmotic
potential of soil water. Agron. J. 71(5): 848-
852; 1979.

Tinus, R. W. Nature and management of pH and
salinity. In: Proceedings of North American
Forest Tree Nursery Soils Workshop; 1980 July 28-
August 1; Syracuse, NY. USDA Forest Service,
Canadian Forestry Service and State University
of New York; 1980: 72-86.

Townsend, A. M. Response of selected tree species
to sodium chloride. J. Am. Soc. Hortic. Sci.
105(6): 878-883; 1980.

Dirr, M. A. Tolerance of honeylocust seedlings
to soil-applied salts. HortScience 9(1): 53-
54; 1974.

Francois, L. E.; Clark, R. A. Salt tolerance of
ornamental shrubs, trees and iceplant. J. Am.
Soc. Hortic. Sci. 103: 280-283; 1978.

Goodman, Les. Simultaneous confidence intervals
for contrasts among multinomial populations.
Annals of Math. Stat. 35(2): 716-725; 1964.

Maas , E. V.; Hoffman, G. J. Crop salt tolerance —
current assessment. Journal of the Irrigation
and Drainage Division. Proceedings of the
American Society of Civil Engineers 103(IR2):
115-134; 1977.

Nassery, H. Salt-induced loss of potassium from
plant roots. New Phytol. 83: 23-27; 1979.

Pasternak, D.; Forti, M. A technique for early
selection of salt-resistant plants. In: Ben-
Gurion University of the Negev, Research and
Development Authority, Applied Research Insti-
tute, Scientific Activities 1978-79. Beer-
Sheva, Israel; 1980: 59.

Rathert, G.; Doering, H. W. Influence of extreme
K:Na ratios and high substrate salinity on
plant metabolism of crops differing in salt
tolerance. J. Plant Nutrition 4(3): 261-277;
1981.

Richards, L. A., ed . Diagnosis and improvement
of saline and alkali soils. Agric. Handb. 60.
Washington, DC: U.S. Department of Agriculture;
1954. 160 p.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT-168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

CONTAINERIZED SEEDLING PRODUCTION FOR FOREST REGENERATION IN THE PACIFIC NORTHWEST

James M. Sedore

ABSTRACT: The containerized seedling continues
to be a valuable regeneration option during this
time of economic stress. Recent developments in
plug-1 culture and seedling storage are
descri bed.

INTRODUCTION

As you know, these are hard times for the timber
industry. The lack of timber harvesting has
reduced the demand for regeneration seedlings.
Seedling orders have been reduced for two years
at our operations, and we see no indication of
any impending leap to the previous levels.
Greenhouse operations throughout the Northwest
have had to respond to this change, and the
response has been varied. One operation has been
almost totally mothballed; another is planning to
consolidate two facilities into one; another is
operating at less than 40 percent capacity and is
looking to move and build a smaller, more
efficient operation. Another operation has
diversified and is growing vegetables in some of
their greenhouses. It has been a time to
prioritize and to reevaluate the value and role
of the container program after little more than a
decade since its birth. Although some operations
have gone by the wayside, the containerized
seedling has retained a place in the regeneration
effort .

It is obvious that the conditions under which we
work in the Pacific Northwest differ
significantly from the conditions in the
i ntermountai n states, especially the region of
the Southwest. I hope that by sharing what we
are doing in the Northwest, you might get an idea
or two that you can apply at your operations.

Therefore, the structure must facilitate both
heating and cooling to provide proper growing
conditions throughout the year.

ENERGY

Fuel represents up to 15 percent of the cost of
our seedlings. Several operations have made
significant reductions in their fuel bills by
sowing later and by switching from diesel oil to
natural gas. Natural gas is the most popular fuel
source in the Northwest because of large supplies
from Canada. Solar collection may be used more in
the future, but the cost to collect and use the
limited solar radiation we receive does not
compete with gas at this time. A recent
greenhouse energy conservation technique is being
used by The Bureau of Land Management at Colton,
Oregon. The BLM uses infra-red heating in one of
their two greenhouses. They report a 30 percent
energy savings over their forced-air system. They
also believe that the quality of their stock has
not diminished.

BENCHES AND CONTAINER TYPES

Bench layouts vary from broad growing troughs,
wooden 2" X 4" saw horses, iron flat bars,
aluminum T-bars, and aisle eliminating bench tops.
The most popular container type is the Styroblock
in either the 2A or the 4A size. Commonly
seedlings grown in a 2A are transplanted to become
plug-l's, and 4A's, are shipped directly to the
forest. Other containers have been used such a
Leech tubes for genetic stock or Spence r-Lemai re
books for Thuja , but the most common container
type is the Styroblock.

GREENHOUSES

The average production facility in the Northwest
produces from two to four million seedlings per
year, although two facilities produce over eight
million per year. Private timber companies own
and operate the largest container complexes for
their own forest regeneration needs. They also
compete for public regeneration contracts. The
greenhouse layouts and designs differ based on
the state-of-the-art at the time the greenhouses
were built. The most popular greenhouse design
at this time calls for a fiberglass roof with
roll up sidewalls. Common regimes call for
heating the greenhouse to 20 C, through May and
minimal heating from October through January.
Passive cooling through roof vents or active
cooling with exhaust fans and evaporative coolers
occurs during the hotter hours of June through
September.

James M. Sedore is Greenhouse Manager, Washington
State Department of Natural Resources, Olympia,
Wash .

SOWING AND FERTILIZING

Most of us sow with some type of vacuum sower
which picks up one seed per hole from a tray of
seed. The seed then falls into the cell when the
vacuum is broken. It is most common to multiple
sow to ensure a germinant in each cell and then
to thin. Soluble fertilizers are mixed according
to each grower's preference and injected into the
watering system. Fertilizer regimes vary
according to species, time of year, and nutrient
status as indicated by foliar and soil analysis.
Most growers contract their soil and foliar
analysis with a private consultant. As is common
with many plants, the growth curve of most conifer
species that we grow is a sigmoid curve. Growth
starts slowly, gradually increases in rate, and
finally tapers off in the fall. To produce a
quality seedling, it is necessary to find the
balance between overfeeding, which produces

succulent, top heavy seedlings and underfeeding
which produces a stunted, starved seedling.

PLUG-l's

If sown in a bareroot seedbed, many of our
seedlings such as Abies , Tsuga , and Thuja do not
grow quickly the first few years. Commonly we
grow these seedlings for one year in the
greenhouse and then transplant them at the
nursery. These seedlings may be transplanted
either in the summer (August, in our area) or in
the spring. We call these seedlings Plug-l's.
In the nursery transplant bed, they can develop
into large enough seedlings to withstand deer
and elk browsing or vegetative competition. The
shoot of a Plug-1 Tsuga is similar to a 2-1 Tsuga ,
but the roots of a Plug-1 are mop-like which can
more easily support the shoot. The hemlock
transplant bed does not have to be shaded or
misted as the seed bed requires, and each crop
uses valuable nursery bed space for only one year
rather than three.

PLUG CULTURE

Back at the greenhouse, seedlings destined to go
directly to the forest are kept unshaded and
exposed to broader and broader temperature
ranges. If you keep temperatures and fertility
levels high, you produce a large, succulent shoot
at the expense of an adequate root system and
caliper. Seedlings, grown in this way, leave the
greenhouse unprepared for the vigors of the
forest and are commonly frozen back, desiccated
or pushed to the ground by the first snow. Our
goal is to produce a seedling with a large
caliper and good buds, tall enough to compete
with surrounding vegetation and with enough roots
to support the shoot.

Techniques for inducing budset vary by species.
It is common for Pseudotsuga to be leeched,
moisture stressed, and then fed a low nitrogen,
high phosphorus and potassium fertilizer in
September to form large, mature buds for winter
planting. However, Tsuga appears to respond best
to full light exposure in July and a balanced
fertilizer each time the seedling requires
moisture. Shading has become less and less
popular among Northwest growers. Although many
of our trees will grow well under shade, when
these seedlings are removed from a shaded house
and planted in a nursery or clear-cut
reforestation site, the seedlings drop their
foliage and must struggle to break bud and begin
growing. To avoid this we attempt to grow the
seedlings without shade.

SEEDLING STORAGE

We have all struggled with the problem of holding
seedlings at lower elevations for late planting
at higher elevations. All too often the
seedlings break bud in the shelterhouse before
the planting site is ready or accessible. Moving

these succulent seedlings in the spring from a
warm, protected nursery to some cold, harsh site
is a frustrating experience for both the
nurseryman and the forester. Growers in the
Northwest have several different approaches to the
problem of seedling storage and I'll share several
of these approaches with you.

The Washington State Department of Natural
Resources moves their seedlings out of the
greenhouse into shel terhouses in June. Here they
remain until packaged for field planting which
traditionally begins the first week of January.
At our location, we feel that this is the time
when the seedlings are fully dormant. The
seedlings are sprayed thoroughly with a foliar
fungicide to reduce damage from storage molds and
one week later the seedlings are packaged and
stored at 2 °C in poly-lined boxes. The seedlings
are kept at this temperature during transport and
until the day of planting. All seedlings stored
this way should be planted by June. Seedlings to
be spring transplanted in the nursery as plug-l's
may be stored in this way or kept in the
shelterhouse. Container stock is transplanted
in mid-March, and plug transplanting is completed
by early April, two weeks before bud burst of
Pseudotsuga in our area. Seedlings are therefore
stored above freezing for 1 to 20 weeks. Storage
molds have not been a major problem in our
program although we lose a few trees each year.
Many nurseries use this method of cooler storage
for coastal and low elevation seedlings.

The Weyerhaeuser Company freezes most of their
high elevation container stock at 1 to 2°C. The
seedlings are packaged in January and February
after having received 400 to 600 hours of exposure
to temperatures below 4°C. Thawing takes from one
to two weeks in a shaded warehouse at 4 to 15 °C,
before the seedlings are shipped to the planting
site. Seedlings are planted shortly after
thawing. For more information, contact Steve Hee
at Weyerhaeuser Regeneration Center in Rochester,
Washington.

The Industrial Forestry Association is a group of
timber companies who share a nursery system for
the reforestation of their individual lands. IFA
does freezer-store container seedlings on request
according to vulnerability criteria. There are
three vulnerability criteria: (1) coastal seed
sources, (2) seedlots which have had a history of
winter damage in the nursery and (3) seedlots that
are likely to suffer significantly from storage
molds. Late in the fall, frost hardiness testing
is begun. The lethal temperature for 50 percent
LT is established by means of controlled
freezing tests. If the seedlings have achieved a
set LT, they are considered liftable and
storable. Seedlings may be stored frozen for six
months. Large quantities may be thawed en masse
at 4 °C, but this takes up to six weeks. Small
quantities may be thawed in a matter of days at 15
°C. Pseudotsuga , Picea and Abi es do not appear to
have any problem with this treatment although
Tsuga roots are sometimes damaged. For more
i nf ormation , contact Sally Johnson at the IFA

Nursery in Toledo, Washington.

The British Columbia Forest Service also freezer
stores many of their seedlings, especially
interior seedlots and seedlots that they suspect
will suffer significantly from disease problems
in storage. When possible, they also make frost
hardiness tests. This has indicated to them
that, at their interior, harsh environment
nurseries, they can begin storing in October but
must wait until mid-December at their coastal
nurseries. They report successful storage of
interior Picea , Pinus , and Abi es at -2 °C. other
seedlings can also be freezer stored but Tsuga
appears to be the most sensitive. In trials at
the nursery, the roots of seedlings frozen six
months do not elongate for 20 days after
planting. Bud burst does not occur until 28 days
after planting. Their freezer storage length may
vary from two to eight months and they are doing
research into the sugar and starch balance in six
month freezer stored seedlings. For more
information, contact Jim Sweeton at the Surrey
Nursery in Surrey, British Columbia.

As you can see, both cooler and freezer storage
are an important part of our regeneration
programs. However, we have not yet worked out a
uniform program. I hope that you'll join us in
developing this technology.

CONTAINER REUSE

After extracting the seedlings from the
containers, the containers are washed and
refilled for use in the next sowing. Blocks can
be reused many times.

THE FUTURE

During this time of economic stress in the
regeneration business, it is significant to note
that the value of the containerized seedling has
withstood cost/benefit analysis. As the demand
for seedlings increases and funds become
available, I expect to see more improvements in
the containerized program. I look for
improvement first in the fertilizer regimes. I
anticipate that we will find that each species
has a different optimum fertilizer, light, and
temperature regime. In fact, I expect to find
differences within species native to different
climatic zones. Through meetings like these, we
can share information but we must continue to try
new ideas and document them. Also, we must
support, encourage, and participate in research
directed at unlocking this information. We must
work systematically at producing a quality plant
at affordable prices which, not only survives,
but flourishes when it is placed in its final
growing site.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT-168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

THE NURSERY TECHNOLOGY COOPERATIVE:

A COORDINATED EFFORT TO IMPROVE SEEDLING QUALITY

Mary L. Duryea and Steven K. Omi

ABSTRACT: The Nursery Technology Cooperative
(NTC) was established July 1, 1982 to improve
the productivity of the Pacific Northwest's
forest tree nursery industry. The NTC and the
two other cooperatives (tree improvement and
vegetation management) in the Department of
Forest Science are aimed at helping to solve
reforestation problems beginning with seed and
ending with a free-to-grow forest stand.
Membership categories in the NTC include (1)
nurseries, (2) seedling users, and (3) special-
ist organizations. Problem areas for Coopera-
tive study are identified and prioritized by
Cooperative members. Our first study, investi-
gating the effects of top pruning on seedling
morphology and field growth and survival, has
been installed at six nurseries. Planning is in
progress for a long-term Cooperative study exa-
mining the effects of selected herbicides on
weeds and seedlings. Other activities in the
Cooperative include (1) a nursery pathology
research project, (2) a tissue culture/vegeta-
tive propagation project, (3) continuing educa-
tion (production of a nursery manual), (4) tech-
nical assistance (compilation of lists of spec-
ialists available to help members), (5) infor-
mation gathering (collection of state-of-the-art
information on compaction, tilth, and drainage),
and (6) a seedling evaluation program.

Objective

The objective of the Cooperative is to improve
the productivity of the Pacific Northwest's
forest tree nursery industry through an
integrated program of coordinated studies,
information sharing, and technical assistance.

Examples of specific needs to be met through
cooperative action are:

1. Better nursery-specific cultural
prescriptions for the improvement of
seedling physiological quality.

2. Improved soil management guidelines for
the maintenance of long-term nursery
productivity.

3. More effective coordination of nursery
and outplanting techniques.

A. Better information sharing among nur-
series, and between nurseries and
related groups such as reforestation
foresters and researchers.

Why Cooperatives?

INTRODUCTION

Origin Of The Nursery Technology Cooperative

Because of the importance of the forest nursery
industry, a task force was appointed by the
Oregon State Forester and the Dean of the School
of Forestry, Oregon State University (OSU), to
study and report on the status of forest nursery
management technology in the Pacific Northwest.
The task force found that the forest nursery
industry wanted more research and educational
assistance, and proposed that a Nursery
Technology Center be established at OSU to
address these needs. The Nursery Technology
Cooperative (NTC) was officially established
July 1, 1982.

Mary L. Duryea is Assistant Professor and
Leader, Nursery Technology Cooperative,
Department of Forest Science, Oregon State
University, Corvallis.

Steven K. Omi is Research Assistant, Nursery
Technology Cooperative, Department of Forest
Science, Oregon State University, Corvallis.

The three cooperatives in the Department of
Forest Science at OSU have been established to
help solve reforestation problems beginning with
seed and ending with a free-to-grow forest
stand. The Tree Improvement Research Coopera-
tive, headed by Thomas Adams, coordinates gene-
tics and breeding research on Pacific Northwest
tree species to enhance tree improvement efforts
in the region. The Nursery Technology
Cooperative, by helping to increase nursery pro-
ductivity, will aid in the better utilization of
improved seed and the matching of high quality
seedlings to planting sites. At the out-
planting stage the CRAFTS Cooperative, headed by
Steven Radosevich, helps to coordinate research
on methods of controlling competing vegetation
in commercial forests of the Pacific Northwest.

Cooperatives enable us to:

1. Define and study useful problems.

2. Reduce fixed costs per cooperator to
study these problems.

3. Investigate treatment x site interac-
tions .

4. Rapidly use results.

5. More effectively share information by
using OSU as a clearinghouse.

Organization

Fifteen members from state and federal agencies
and industry participated in the Cooperative in
its first year (Appendix 1). A Technical
Committee and a Policy Committee assist the NTC
leadership. The Policy Committee advises the
Cooperative Leader on decisions concerning
program strategy, size, and support. The
Technical Committee helps to identify and
prioritize problems, and assists in planning,
installing, and measuring Cooperative studies.
Together, the Policy and Technical Committees
guide the activities of the Cooperative,
insuring that efforts are focused on real
problems .

The NTC membership categories (and annual mem-
bership fees) are: (1) nurseries (large — $6,000
and small — $3,000), (2) seedling users (full —
$4,000 and monitoring — $2,000), and (3) spe-
cialist organizations ($2,000 to $4,000). All
members (except for the seedling user monitoring
members) have representation on the Technical
and Policy Committees, and are directly involved
in nursery and outplanting studies. Seedling
user monitoring members receive study results
only, and do not participate in guidance.

Figure 1. — Top pruning with a rotary mower at
the D.L. Phipps Forest Nursery (Oregon State
Department of Forestry) .

ACTIVITIES

Cooperative Studies

Problem areas for study are identified and
prioritized by Cooperative members. Top pruning
and weed control will be investigated in our
first short-term and long-term studies, respec-
tively.

Top pruning. — This study was installed in May,
1983, to examine the effects of top pruning on
2+0 Douglas-fir seedling morphology, survival,
and growth. Top pruning is a common practice in
western nurseries (fig. 1); however, there is
little available information about the effects
of top pruning. Treatments for the experiment
include two different pruning heights, two dif-
ferent times of application, and one multiple
pruning. The entire experiment, with one seed
zone was replicated at three nurseries; a
smaller version, involving fewer treatments, was
included so that more seed sources could be
tested. In total, six nurseries (fig. 2) and
nine seed zones are involved in the study. Test
seedlings from each seed zone will be planted on
sites located within their respective zones. In
addition, a common garden study, including seed-
lings from all seed zones, will be established
at the OSU McDonald Forest. The growth and sur-
vival of outplanted seedlings will be monitored
for up to three years.

NURSERY

1. Lava Nursery, Inc.

2. State of Oregon

D.L Phipps Forest Nursery

3. U S D A Forest Service
Humboldt Nursery

4. U S DA Forest Service

J. Herbert Stone Nursery

5. U.S. D A. Forest Service
Placerville Nursery

6. Washington Department
of Natural Resources

Lt. Mike Webster Nursery

Figure 2. — Map showing the location of the six
nurseries where the top pruning study has been
installed .

Weed control. — Planning is in progress for a
long-term Cooperative study that will examine
the effect of selected herbicides on weeds and
seedlings. Presently used methods of weed
control (e.g., handweeding, fumigation) are
costly and may be detrimental to tree seedlings
and soil microorganisms. The objective of this
study will be to screen new and currently
available herbicides for their effectiveness in
controlling weeds without injuring conifer
seedlings. Additionally, we want to determine
the residual effect of herbicides on weeds and
crop species.

Other Cooperative Projects

Two other OSU projects are connected with the
NTC: the Nursery Pathology Research Project,
headed by Everett Hansen, and the Tissue
Culture/Vegetative Propagation Project, headed
by Joe Zaerr. Both projects are meeting
Cooperative objectives, although both are funded
by sources other than Cooperative annual fees.

Nursery pathology research project. — The broad
goal is to provide the biological information
necessary to predict and prevent disease
outbreaks in nurseries. The initial focus of
the project will be on the various top blight
diseases that have caused substantial loss in
recent years. In preliminary work, systematic
isolations have been made from blighted
seedlings at a Pacific Northwest nursery to
identify suspected pathogens. These isolates,
plus those from three other participating nur-
series, will be tested for pathogenicity.
Timing, environmental, and predisposing factors
that influence infection will be determined for
the identified pathogens.

Tissue culture /vegetative propagation pro j ect . —
The objective of this project is to develop
techniques for producing large quantities of
superior forest trees by means of tissue
culture. The approach has been to measure
growth hormones in cultures and to determine
which hormones produce the desired results.
Work to date has resulted in the development of
techniques to isolate and detect plant hormones
in extremely small quantities. These techniques
have been used to measure auxin in callus
cultures and in cultured buds. Cytokinins,
another class of growth hormones, were measured
in suspension cultures of Douglas-fir. The
results of these studies indicate that the
growth hormone requirements for embryogenesis
(producing whole plants from cell cultures) pro-
bably are very specific, and that the growth
hormones that have been used in previous
attempts to produce embryogenesis are probably
not the ones that should be used.

Future work will include a broadening of the
objective to include other methods of propaga-
tion, such as the rooting of cuttings, and the
problems associated with those techniques.

Continuing Education

The Forest Nursery Manual: Production of
Bareroot Seedlings includes 30 chapters covering
specific topics such as nursery site selection,
fertility management, and seedling storage (fig.
3). A comprehensive survey of Northwest nur-
series provided the authors of each chapter with
information on current cultural practices. In
addition, each chapter contains a state-of-the-
art review of nursery research. A workshop held
at OSU in October, 1982 previewed the manual for
over 250 people. The manual will be published
this summer, 1983. Both the Manual and the
workshop have been co-sponsored with the USDA
Forest Service, State and Private Forestry,
Region 6.

FOREST NURSERY MANUAL:

PRODUCTION OF BAREROOT SEEDLINGS

Mary Duryea and Tom Landis, Editors

Development of the Nursery Manual:
a synthesis of current practices and
research

II.

Developing a Forest Tree Nursery

III.

Starting the Bareroot Seedling

IV.

Managing the Soil and Water

Culturing the Bareroot Seedling

VI.

Harvesting and Planting the Bareroot
S eedling

VII.

Selected Topics in Nursery Management

VIII.

Upgrading Nursery Practices

Figure 3. — Major Sections in the 30-chapter
Forest Nursery Manual.

Seedling Physiology and Reforestation Success
will be the title of the Physiology Working
Group Technical Session to be held at the
Society of American Foresters (SAF) National
Convention in Portland this October, 1983. The
one-day session will include both overview and
specific research reports concerning the effects
of seedling physiology on reforestation success,
with major emphasis on stock quality and
planting site manipulation. The proceedings of
the session will be published in 1984.

Technical Assistance

As part of our commitment to improve information
flow and technical assistance, we are compiling
lists of specialists who would like to help nur-
series and reforestation people. Questionnaires
(fig. 4) have already been sent to insect/
disease, soils, weed control, and irrigation
specialists, seedling physiologists, and silvi-
culturists. A very positive response has been
received — many have expressed a strong desire to
be involved in workshops, Cooperative studies,
and problem solving. Other specialists who will
be contacted include agricultural and industrial
engineers, seed physiologists, crop scientists,
and horticulturists. The list of specialists
for insect and disease, soil, and irrigation
problems have been sent to Cooperative members.

Members are encouraged to contact specialists
directly from these lists when the need for
technical assistance arises. However, they may
also receive help from the NTC staff in making
contacts with specialists by stating their spe-
cific problem on a Technical Assistance Request
Form. The NTC staff responds immediately to
these requests by providing ways to approach the
stated problem.

Information Gathering

Cooperative members have expressed a need for
being informed of the state-of-the-art knowledge
on several topics. Soil management (tilth/
compaction/drainage) has been selected as the
problem area in which information gathering is
currently needed. The NTC staff is presently
reviewing the literature and collecting relevant
material. A summary, available to all members,
will follow.

Seedling Evaluation Program

The purpose of the NTC Seedling Evaluation
Program is to improve techniques for assessing
seedling quality. As part of this program, the
NTC provides a seedling vigor evaluation (or
stress testing) service. More than 250 seedling
lots were evaluated this year on a fee basis.
This procedure is designed to identify poor
quality lots by monitoring the growth and sur-
vival of potted seedlings placed in a growth
room after exposure to hot-dry conditions.
Although this procedure has been very useful,
work continues to refine the test. A study is
being conducted to determine the effectiveness
of the current procedure in predicting field
survival under uniform planting conditions. We
are also examining the relationship between the
vigor evaluation results and standard measure-
ments of root growth capacity. This investiga-
tion will indicate whether these two assessment
procedures are consistent in predicting field
survival or, perhaps, are complementary and
could be used together to improve prediction
accuracy. The study began in March, 1983.

SPECIALIST QUESTIONNAIRE
Nursery Technology Cooperative

Name Affiliation

Address

Phone Number

IN THIS QUESTIONNAIRE WE ARE SEEKING
INDICATIONS OF INTEREST AND NOT NECESSARILY A
FIRM COMMITMENT TO PARTICIPATE.

1. a. Would you be interested in being

involved in the Nursery Technology
Cooperative? (check yes or no)

Yes No

b. In what cooperative efforts might you
be willing to participate? (check
yes or no for each starred (*) area
below)

Yes No

(1) *Workshop teaching?

(2) Studies:

*Review of study
plans ?

*Active involvement
in experiments?

(3) *Team problem solving
and providing tech-
nical assistance
through the
Cooperative?

(4) individual direct
consulting?

(5) *0thers? (please
specify below)

Figure 4. — Page one of the questionnaire being
sent to specialists in the West.

Another recently completed study in the NTC
Seedling Evaluation Program was aimed at deve-
loping a specific procedure for detecting damage
to seedlings which have been unintentionally
frozen during cold storage. In this study, we
found that a pressure chamber could be effec-
tively used to identify this type of injury.
Results indicate that the change in plant mois-

ture stress (PMS) of potted seedlings during the
first week after freezing can generally predict
whether or not they will survive. The PMS of
damaged seedlings tends to increase much more
rapidly than that of non-injured seedlings. A
more complete description of this study is
reported by Douglas McCreary in this proceedings.

LOOKING AHEAD

In its second year the NTC staff is (1) coor-
dinating the NTC studies (top pruning, weed
control), (2) providing continuing education
programs (Physiology Workshop at the SAF
National Convention, publication of the Forest
Nursery Manual), (3) updating the Seedling
Evaluation Program, (4) supporting other pro-
jects within the NTC (Nursery Pathology, Tissue
Culture /Vegetative Propagation), (5) providing
technical assistance (compilation of specialists
lists), and (6) gathering information on soil
management, and, given continued Technical
Committee interest, a soil management study
plan will be prepared.

APPENDIX I

Members of the Nursery Technology Cooperative.

Nurseries :

Lava Nursery, Inc.

Oregon State Department of
Forestry, D. L. Phipps Forest
Nursery

USDA Forest Service, Rogue
River National Forest, J.
Herbert Stone Nursery

Washington State Department
of Natural Resources, Lt .
Mike Webster Nursery

Weyerhaeuser Company

Seedling Users:

BLM — Coos Bay District

BLM — Eugene District

BLM — Medford District

BLM — Oregon State Office

BLM — Roseburg District

BLM — Salem District

USDA Forest Service, Umpqua
National Forest

Specialist Organizations:

USDA Forest Service, Pacific
Northwest Forest and Range
Experiment Station

USDA Forest Service, Pacific
Southwest Forest and Range
Experiment Station

USDA Forest Service, State and
Private Forestry, Region 6

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT- 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

USING A PRESSURE CHAMBER TO DETECT DAMAGE TO
SEEDLINGS ACCIDENTALLY FROZEN DURING COLD STORAGE
Douglas D. McCreary

ABSTRACT: During cold storage, seedlings are
sometimes accidentally frozen. A study to
determine if a pressure-chamber device could be
used to detect the extent of this type of injury
indicated that the change in plant moisture
stress of potted seedlings during the first week
after freezing is a reliable measure for pre-
dicting seedling survival.

INTRODUCTION

Storage of bareroot seedlings is often a
necessary step in the reforestation of conifers,
as labor, geographic, and climatic constraints
make it virtually impossible to plant seedlings
immediately after they are lifted. It is well
established that the temperature during storage
can greatly affect seedling quality (Hocking and
Nyland 1971). Currently, most conifer seedlings
are stored between 0° and 3°C because cold tem-
peratures reduce respiration and inhibit the
development of harmful molds. But, despite
improvements in the overall quality of refrigera-
tion facilities, occasional equipment malfunc-
tions result in seedlings being exposed to
subfreezing temperatures. Such exposure can be
especially injurious to root systems, which are
more sensitive to freezing than shoots.
Unfortunately we know little about the tolerance
of roots to this type of injury, nor is there a
simple and effective method of identifying its
extent. When such a storage problem is discov-
ered and it must be decided whether seedlings
should be discarded or planted, there is little
on which to base a decision. Consequently, in
December 1982, as part of the Nursery Technology
Cooperative at Oregon State University, we ini-
tiated a study to determine if a pressure-
chamber device could be effectively used to
identify seedlings that were severely damaged by
accidental freezing during storage.

METHODS

One hundred, 2-year-old Douglas-fir (Pseudotsuga
menziesii (Mirb.) Franco) seedlings from a com-
mon seed source were randomly divided into 10
equal groups for 10 temperature treatments.
Each group was placed in a sealed plastic bag in
a freezing chamber programmed to remain 1 hour
at +1°C. The temperature was then lowered at

Douglas D. McCreary is Research Assistant in the
Department of Forest Science, School of
Forestry, Oregon State University, Corvallis,
Oregon.

the rate of 2°C per hour. We removed the first
bag at -3°C and continued to remove one bag
every half hour at each drop of 1 °C until the
temperature was -12°C. Immediately after
removal from the freezing chamber, each bag was
placed in a cold room (+1°C) and left overnight
to thaw gradually.

The day after thawing, all seedlings were tagged
with their freezing-treatment number and planted
randomly in pots, one seedling from each treat-
ment in each pot.

The following day, a small lateral branch from
each seedling was removed and placed in a
pressure chamber to determine its plant moisture
stress (PMS). This procedure was repeated on
the fourth and sixth days after potting. PMS
was recorded as a positive number, so that an
increase indicated greater water deficit within
the seedlings. The night before each PMS deter-
mination, all pots were watered to field capa-
city to ensure similar soil moisture conditions
for each pot on each evaluation date.

The seedlings were maintained for 2 months in a
growth room under a 16-hour photoperiod and
constant 22°C temperature. During this time,
the pots were watered regularly and soil
moisture remained fairly high. At the end of
this period, we recorded the percentage of dead
seedlings from each of the 10 freezing treat-
ments and calculated the average PMS per treat-
ment for each assessment date. For each
treatment, we calculated the average absolute
increase and average percentage increase in PMS
between the first and fourth and the first and
sixth days after planting.

We then determined if there was a significant
relationship between freezing temperature and
PMS on each date. Next we calculated correla-
tion coefficients for the relationships between
mortality and absolute and percentage changes in
PMS over all treatments. Finally, we determined
the average PMS for seedlings that lived and
those that died and tested for significant dif-
ferences. All reported differences were signi-
ficant at P = 0.01 unless otherwise stated.

RESULTS

Twenty of the original 100 seedlings died during
the 2-month assessment period. Figure 1 shows
mortality percentages for each freezing treat-
ment. Sixteen of the dead seedlings were from
the two lowest temperatures, which indicates
that among seedlings of the seed source used,

100 — 1
90 -
80-
_ TO -
. 60-

O 4°
30 -

20 -
10

■ 1 1 r

"3 -4 -5 "6 -7 -8 -9 -10 -I I -12
FREEZING TEMPERATURE (°C)

Figure 1. — Final mortality of seedlings, by-
freezing treatment.

30-1

-4 -5 -6 "7 -8 "9 -10 "I I
FREEZING TEMPERATURE l°C]

Figure 2. — Average plant moisture stress of
seedlings, by treatment and day of evaluation.

the threshold temperature for lethal damage
(-11°C) was quite uniform. Figure 2 shows

to
to

32-
30-
28 ■
24- ■
20 •
16-
12-
8

4 -

DAY 6

DAY 4

DAY

LIVE

DEAD

Figure 3. — Average plant moisture stress of sur-
viving and dead seedlings.

average PMS by treatment for each assessment
date. There are three interesting things to
note: first, that average PMS for all treat-
ments increased over time; second, that first-
day PMS tended to be lower in the colder treat-
ments (freezing temperature and PMS were signi-
ficantly and positively correlated); and third,
that this initial trend dramatically reversed
during the following 5 days. Seedlings from the
two coldest treatments had the highest average
PMS values on the sixth day after planting, and
freezing temperature and PMS were significantly
(P = 0.05) and negatively correlated.

The relationships between lethal freezing injury
and PMS (fig. 3) show that seedlings that died
had significantly lower initial PMS values that
then rose precipitously. Seedlings that lived
had higher initial PMS values that increased
gradually between the first and fourth days and
then remained relatively unchanged. PMS on the
sixth day, and the percentage difference between
the first and sixth days, were significantly
higher for those seedlings that eventually died.

As might be expected from this discussion, the
percentage of dead seedlings from a given
freezing treatment was closely correlated with
the absolute and percentage increase in PMS for
that treatment. There was a strong correlation
between mortality and both absolute and percen-
tage increases in PMS for both measurement
intervals (days 1 to 4, days 1 to 6).
Significant correlation coefficents were:

Percentage mortality x absolute increase in PMS
Days 1 to A r = 0.80

Days 1 to 6 r = 0.98

Percentage mortality x percentage increase in
PMS

Days 1 to 4 r = 0.85

Days 1 to 6 r = 0.96

Although all correlations were significant, the
larger coefficents for the longer time intervals
indicate that predictions of mortality from PMS

change are more reliable after 5 days than after
3 days.

CONCLUSIONS

Our initial hypothesis was that accidental
freezing during cold storage can injure root
systems, so that seedlings cannot take up water
and maintain an adequate moisture status once
they are planted. The data are consistent with
this view. Seedlings killed by the freezing
treatments became more stressed over time than
seedlings that lived, although they initially
had lower PMS. An initial reduction, also found
by Bixby and Brown (1974) and Timmis (1976), is
apparently caused by internal rupturing of cells
and release of water into the xylem. Over time,
the transpirational demand probably depletes the
available water in the seedlings, and PMS rises
rapidly as the water is not replenished by the
injured root system.

PUBLICATIONS CITED

Bixby, J. A.; Brown, G. N. Rapid determination
of cold hardiness in black locust seedlings
using a pressure chamber. Abstract No. 12.
Boulder, CO: North American Forest Biology
Workshop; 1974: 354.

Hocking, Drake; Nyland, Ralph D. Cold storage of
coniferous seedlings. Research Report No. 6.
Syracuse, NY: Applied Forest Research Institute,
State University College of Forestry; 1971. 70 p.

Timmis, Roger. Methods of screening tree seedlings
for frost hardiness. In: Connell, M. G. R. , Last
F. T. , eds. Tree physiology for yield improvement
New York, NY: Academic Press; 1976: 421-435.

Because we found considerable variability in the
initial PMS values of seedlings receiving the
same freezing treatment, and because the change
in PMS was so closely correlated with lethal
injury, we believe that the procedure outlined —
measuring seedlings once soon after planting and
once 5 days later — is a more reliable technique
for predicting injury than a single PMS measure-
ment. The exact magnitude of change in PMS that
indicates severe freezing damage, however, is
not clear. In this study, a 4-fold increase
between the first and sixth days reliably indi-
cated seedling mortality; those with less than a
4-fold increase in PMS lived. The 4-fold
separation value predicted the final survival
status of 97 percent of the seedlings. In pre-
liminary results from another trial, however, a
3-fold increase during the first week after
planting indicated mortality. In this second
trial, there was little or no change in the PMS
values over time for most surviving seedlings,
in contrast to the rough doubling of PMS between
the first and sixth days for surviving seedlings
in the study reported here.

Although some calibration must be done to per-
fect the technique, the data clearly suggest
that a pressure chamber can be a very useful
tool in identifying seedling injury caused by
unintentional freezing during cold storage. The
assessment procedure outlined is simple,
requiring only a pressure chamber and a small
amount of greenhouse or growth-room space, and
it can be completed within a week after the
suspected injury occurs.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT- 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

ASEXUAL VS. SEXUAL PROPAGATION OF QUAKING ASPEN

Robert B. Campbell, Jr.

ABSTRACT: Quaking aspen (Populus tremuloides
Michx.) regenerates almost exclusively by root
suckers in the western United States, even though
female clones produce abundant viable seed.
During the past decade, interest in propagating
aspen for use as an ornamental and for
revegetation of forest land has increased. To
satisfy these diverse needs for aspen planting
stock, nurserymen have a choice between sexual
and asexual propagation. Criteria for clone
selection, suggestions for root and seed
collection and storage, propagation techniques,
and the advantages of both sexual and asexual
propagation are discussed.

INTRODUCTION

Quaking aspen (Populus tremuloides Michx.) has
the widest distribution of any native tree
species in North America (Fowells 1965) . This
significant fact suggests that quaking aspen can
grow under a vast range of environmental
conditions. Thus, if aspen could be successfully
propagated, it could be used widely as an
ornamental and for reforestation and land
reclamation. In the western United States, this
important species relies almost entirely upon
vegetative regeneration from root suckers.
Female clones, however, produce many viable
seeds .

Interest in propagating quaking aspen for use as
an ornamental and for reforestation surged during
the past decade. Vegetative propagation techniques
have been developed (Schier 1978b) and have
specific advantages. However, seed propagation
is less labor intensive and is used by some
nurseries to produce large quantities of planting
stock.

I will present various factors that nurserymen
should consider before selecting between sexual
and asexual methods of propagating aspen.

ASEXUAL PROPAGATION

Quaking aspen clones have numerous long, lateral
roots in the top 6 inches of the soil profile.
Suckers may arise along these roots and become a
younger generation of ramets that are genetically
identical to the trees of the parent clone.

Robert B. Campbell, Jr. is a botanist with the
Intermountain Forest and Range Experiment
Station, USDA Forest Service, located at the
Forestry Sciences Laboratory, Logan, Utah.

Many amateur and professional landscapers
transplant these natural suckers, or wildlings,
for ornamental purposes. When the wildlings are
dug up, the soil usually falls away exposing the
root system. Typically, the transplant's root
system consists of only a 12- to 18 inch segment
of lateral root from the parent clone. Once
transplanted, the wildlings usually grow slowly
at first and develop small leaves. Generally
they have few, if any, branch roots at the time
they are removed from the parent clone, and the
existing root system is inadequate; consequently
many wildlings do not survive after transplanting
(Schier 1982).

A few commercial landscapers report good survival
and growth of transplanted aspen when the suckers
have well-developed, independent root systems.
They are careful to keep the root ball tightly
bound, which protects the fragile new roots.
Sharp shovels are used to minimize root damage,
which can be an infection site for pathogens. It
is best to transplant aspen in the dormant stage.
Survival can be excellent when aspen 3 to 5
inches diameter at breast height (d.b.h.) and 18
to 20 ft tall are carefully transplanted with a
44-inch tree spade. (Personal communication with
Ron McFarland of Landscaper's Service, Steamboat
Springs , Colo . )

Another nurseryman substantially improves the
survival and vigor of transplanted wildlings as
follows: (1) Wildlings are selected from
undisturbed clones where the regeneration varies
in size and age. (Failure apparently is common
when wildlings come from clones with a history of
disturbance as characterized by many suckers of
the same age.) (2) When trees 3 to 5 inches
d.b.h. are transplanted, the trees are first
wiggled and only those trees that are firmly
rooted in all four directions are selected. (3)
After transplanting, the aspen are given three
applications of a complete foliar fertilizer and
one hydraulic injection of the fertilizer into
the root system. (4) The trees are sprayed with
Benomyl (a systemic fungicide) to reduce the
incidence of fungal pathogens common to aspen.
(Personal communication with Jerry Morris of
Rocky Mountain Tree Experts, Lakewood, Colo.)

Methods have been developed to artificially
propagate aspen vegetatively (Schier 1978b).
Though labor intensive, these methods offer a way
to produce rooted aspen suckers capable of
vigorous growth. I want to dispel the myth that
vegetatively propagated aspen inherently have
slow growth. Aspen trees propagated vegetatively
14 years ago at Logan, Utah, are now 32 ft tall.

Clone Selection

In 1976, aspen suckers were propagated
vegetatively from 10 healthy and 10 deteriorating
clones in Logan Canyon. Schier and Campbell
(1980) describe the site and suckering
characteristics for these 20 clones. The two
groups of clones differed appreciably with
respect to aspen density, basal area, and
mortality .

The rooted sucker cuttings were planted in tubes,
2.5 inches in diameter by 10 inches long, filled
with peat moss : vermiculite (1:1) and placed in
the greenhouse. The next spring the suckers were
transplanted to peat moss: sand (3:2) in 1 gal
pots and moved to the lathhouse. Under the
direction of Dr. George A. Schier, the young trees
were transplanted during spring 1978 to a common
garden at the Green Canyon Nursery 3 miles
northeast of Utah State University.

A total of 439 aspen were planted randomly in 15
rows of up to 30 individuals per row with a
6.6-ft spacing. Soil amendments and fertilizers
were not used at the nursery. Rainbird
sprinklers provided regular but moderate
irrigation. After 2 years at the nursery, the
trees had substantial variation in height growth.
In an attempt to standardize subsequent
vegetative growth, all stems were cut off at
ground level in the spring of 1980. Thus all new
suckers started from established root systems.
As new suckers arose, a dominant sucker was
selected; all other remaining and subsequent
suckers were cut off.

The new suckers are now in their fourth growing
season, and some trees are over 12 ft tall. Data
recorded include: height growth for each year,
the number of lateral branches, the length of the
longest three laterals, and stem form.
Preliminary results indicate that substantial
variation in these morphological traits occurs
between clones. Also, clonal variation is
obvious for the time of leaf flush, leaf size and
shape, and the angle of branching between the
main stem and lateral branches. This
common-garden planting illustrates well the
genetic control of these characteristics in
aspen.

The survival rate in the common garden is an
impressive 99 percent. Of the 439 aspen planted,
only three died; two others were stolen.
Although a few trees have poor growth, at least
95 percent have acceptable growth.

Many factors should be considered when selecting
a clone for asexual propagation. Do the trees in
the clone have a desired shape and appearance?
Is the soil type desirable for root collection?
Are there abundant (or sufficient) lateral roots
near the soil surface? Will the roots collected
have a high capacity to sucker, and will the
sucker cuttings develop roots? (Preliminary
trials are suggested to determine the clone's
suckering and rooting capabilities.) These
questions relate to specific factors that vary
greatly among clones in nature.

Tree height may be a misleading guide for
acceptance or rejection of a prospective clone.
Environmental conditions, particularly those
related to available moisture, strongly influence
height growth. One would expect trees
vegetatively propagated from a clone with tall
trees to grow reasonably tall; however, I have
seen suckers propagated from clones with short
trees on a poor site grow unusually fast and tall
in a better environment.

Harniss and Nelson (in press) indicate that aspen
clones vary in susceptibility to Marssonina , a
fungal leaf blight. They surveyed about 1,000
acres of aspen in northern Utah during a recent
epidemic year for Marssonina . Resistant or
lightly infected aspen trees occupied only 18
percent of the total area. They suggest that the
best control of this leaf blight, particularly
for ornamental and revegetation purposes, would
be to select for highly resistant clones.

Numerous desirable traits of specific aspen
clones can be perpetuated by vegetative
propagation. Barnes (1966) suggests that the
following characteristics are generally uniform
among the ramets of the same clone: leaf size,
shape, and color (both spring and fall);
phenology; stem form and branching habit (for
example, excurrent growth or wide spreading crown
and degree of self-pruning); sex; bark color and
texture; and tendency for disease and insect
attack. These traits may be important to
consider when a clone is selected.

Root Collection and Storage

Schier (1978b) explains in detail the root
collection process. He mentions specific
advantages for using a spade, an anvil-type
pruner, and a moist cloth bag for collecting
lateral roots that range from 0.4 to 1.0 inch in
diameter .

The season of root collection can significantly
alter the number of suckers produced. During the
spring flush and early shoot growth, the roots of
aspen clones have high levels of auxin, which
reduces sucker formation (Schier 1973). Schier
(1978b) explains that roots collected during the
clone's dormant stage (early spring, later
summer, or fall) typically yield more suckers
than those collected during active growth. He
notes that early spring collections are easier to
make and result in less root damage because the
soil is still moist.

Perala (1978) and Schier (1978a) report that the
number of aspen suckers produced is not related
to the length of the root cuttings. Because the
length is not a critical factor, roots can be cut
for the convenience of tray size and available
space .

Schier and Campbell (1978) suggest that in some
situations it may be useful to hold aspen roots
in cold storage before planting the roots to
begin the suckering process. For example,
nurserymen could have the flexibility to collect

roots from clones at different times, hold them
in cold storage, and then plant the roots at the
same time. In addition, the first growing season
for the new suckers could be lengthened if the
roots were collected in the fall, stored, and
then planted in the greenhouse during late
winter. Schier and Campbell (1978) treated root
segments with Benomyl, wrapped them in moist
paper towels, placed them in glastic bags, and
stored them in the dark at 36 F for up to 25
weeks. In most cases the cold storage did not
significantly alter the number of suckers
produced by the roots. They suggest that roots
from most clones can be stored for extended
periods of time and still produce suckers
suitable for propagation. Even after storing
root cuttings from three clones for 12 months in
a cold room, I found that some suckers still
arose from the roots. When the remaining roots
from the same lot were tested next at 18 months,
they were rotten and did not sucker.

Propagation Method

Briefly, procedures developed by Schier (1978b)
to vegetatively reproduced aspen are: (1)
Collect lateral roots from desirable clones. (2)
Clean the roots, cut to suitable lengths, treat
root segments with Benomyl, and plant them
horizontally at a depth of 0.5 inch in trays of
vermiculite. (3) Place the trays in a
greenhouse, water lightly each day, and allow the
root segments to sucker for 6 weeks. (4) Cut the
new suckers from the root segments, treat the
suckers' bases with indolebutyric acid (IBA) , and
plant the sucker cuttings in moist
vermiculite : perlite (1:1). (5) Put these
cuttings on a misting bench for 2 to 3 weeks to
root. (6) Transplant the rooted cuttings to
containers with peat moss : vermiculite (1:1) and
apply a complete fertilizer. Use supplemental
light during short days and maintain the
temperature between 59 and 77 F. Aspen have
winter chilling requirements that are satisfied
at 36° to 50° F.

SEXUAL PROPAGATION

Female aspen clones produce highly viable seed in
the spring (Fowells 1965; McDonough 1979).
Growing aspen from seed is less labor intensive
than the asexual methods discussed above. Some
nurserymen are growing seedling aspen on a
production scale. Native Plants, Inc. presently
has in its nursery several hundred thousand aspen
seedlings of various sizes, both as bare root
stock and in containers (personal communication
with Mike Alder, Native Plants, Inc., Salt Lake
City, Utah).

I will comment on several items that may be
useful to nurserymen who wish to propagate aspen
from seed.

Clone Selection

Not all aspen clones bear seeds. Typically,

aspen have imperfect flowers arranged in catkins.
With few exceptions, all of the catkins produced
in a clone will be the same sex. Reports in the
literature suggest that the male to female ratio
of aspen clones varies in some areas in favor of
the male (Fowells 1965, Grant and Mitton 1979).
From my general observations, I believe that only
20 to 25 percent of the clones in the West will
set seed in any one year. Thus, finding female
clones with seed is a major limitation for clone
selection.

Before flowering, the winter floral buds usually
can be picked apart and carefully observed with a
hand lens to determine the sex. The best time to
determine the clone's sex is mid- to late spring
when the catkins are extended. The male catkins
have a cluster of purple anther sacs on each
scaly bract. The female catkins have a single,
green, top-shaped capsule at each bract.
Although catkins disintegrate rapidly after
shedding pollen or seed, enough fragments to
identify the clone's sex usually will remain on
the duff layer throughout most of the summer.
Emphasis should be placed on finding female
clones with desirable attributes for the proposed
use of the new seedlings. Nevertheless, because
of genetic recombination the seedlings will not
be exactly like the trees in the female clone.
The odds for desirable offspring, however, should
be better if the female clone has the preferred
characteristics .

Seed Collection

Aspen flowering is controlled in part by
temperature. Because of this, the same clone may
vary up to 3 weeks in date of flowering from year
to year. Temperature also affects flowering
phenology along elevational gradients, with
earliest flowering beginning at the lower
elevations. In northern Utah male and female
catkins usually begin to emerge in mid- to late
April. The male catkins soon elongate and the
clusters of purple anther sacs begin to shed
pollen. Following pollination, some 4 weeks
later as the leaves begin to flush out, the
female catkins elongate as the seeds mature and
the green capsules swell. One to 2 weeks later
the capsules open and shed the seed in a fluff of
cottonlike hairs.

Rather than collecting the cottony fluff in the
field, use a long pruner to cut branches from
trees with female catkins about a week before the
seed would ordinarily be shed. The catkins can
then be forced in a greenhouse or laboratory.

A method commonly used in Europe for seed harvest
from European aspen (Populus tremula) will also
work for quaking aspen. The cut ends of the
catkin-bearing branches are placed in containers
filled with water. Water is added as needed and
kept at a temperature of 46 to 50 F. High air
temperatures (68° to 104° F) , low relative
humidity, and gentle ventilation quicken the
ripening process. The catkins should not be
exposed to full sunlight. When the capsules
open, a suction device is used to remove the

cotton and seed. The seed will separate from the
cotton as the air current passes through a series
of three cylinders connected by small tubes. The
viable seed accumulates in the first two
cylinders (FAO 1979).

Aspen seed need not be removed from the cotton
for germination, but cleaned seed is easier to
handle. The mature seed is tan, plump, and
small; Schreiner (1974) indicates there are about
3 million cleaned seeds per pound.

Seed Viability and Storage

McDonough (1979) stresses that aspen in the West
produce ample amounts of nondormant, germinable
seed. However, inadequate soil moisture during
germination and early seedling growth usually
prevents establishment under field conditions.
He found germination capacities of 90 to 100
percent at temperatures from 36 to 86 F.
Germination began within 8 to 12 h when
temperatures were 68 to 95 F. Also, seeds air
dried for 2 days at 68 F and then stored in
vapor-tight bottles at 28 F for 48 weeks
retained 90 percent or better germinability .

McDonough (1979) shows that the depth of planting
greatly affects seedling emergence, which
decreases significantly if the seed is placed
deeper than 0.15 inch below the surface.
Greenhouse seedbeds and standard potting soils
are suitable for germination and seedling
establishment when watered gently.

Poplar seed can be stored for several years with
only a slight decline in the germination rate if
stored in a cool, closed container with low
humidity (FAO 1979). Fowells (1965) explains
that good seed crops for aspen occur every 4 to 5
years, with only light seed production in the
other years. Nurserymen could collect seed
during the years of abundant seed and store it
for a few years without appreciable declines in
germination potential.

In contrast, vegetative propagation yields new
ramets genetically identical to the parent.
Nurserymen can select for the superior clonal
traits preferred by their clientele. The future
for asexual propagation of aspen is promising
with many possibilities for new advances. In
fact, tissue culture, another form of vegetative
propagation, is currently being used by Native
Plants, Inc. to grow tens of thousands of aspen
plantlets from a single seedling tree that has
superior traits (personal communication with Mike
Alder, Native Plants, Inc., Salt Lake City,
Utah) .

I stress two recommendations that apply to both
methods. General wisdom indicates that clones
selected for either root or seed collection
should be in the same general area and elevation
as the anticipated outplanting, whenever
possible. Also, aspen respond best when the
fertilizers applied contain a full complement of
macro- and micronutrients .

Aspen can be readily propagated by either sexual
or asexual methods, both of which have unique
advantages. Nurserymen are challenged to
capitalize on these advantages to produce aspen
stock tailored for specific uses.

PUBLICATIONS CITED

Barnes, Burton V. The clonal growth habit of

American aspens. Ecology. 47(3): 439-447; 1966.

Food and Agriculture Organization of the United
Nations. FAO Forestry Series No. 10: Poplars an
willows in wood production and land use. Rome:
Food and Agriculture Organization of the United
Nations; 1979. 328 p.

Fowells, H. A. Quaking aspen (Populus tremuloides
Michx.). In: Silvics of forest trees of the
United States. Agric. Handb . 271. Washington,
DC: U.S. Department of Agriculture, Forest
Service; 1965: 523-534.

We collected seed in May 1979 from one clone in
northern Utah, air dried the seed for 2 days, and

then stored it in a sealed plastic envelope at

36 F. Initially the germination rate was 94
percent. I tested the seed lot in April 1982 and
observed a 92 percent germination capacity. In
April 1983, after 4 years of cold storage, the
seeds still had 82 percent germinability.

DISCUSSION

The propagation of aspen from seed requires less
equipment, labor, time, and space than intensive
vegetative methods of propagation. In addition
a large outplanting of seedling stock tends to
maximize the genetic variation available in the
gene pool. Such variation is a benefit to
reforestation and land reclamation because it
enhances the adaptability and survival of the
total outplanting. These uses normally require
large numbers of planting stock that are more
feasible to grow from seed.

Grant, Michael C. ; Mitton, Jeffry B. Elevational
gradients in adult sex ratios and sexual
differentiation in vegetative growth rates of
Populus tremuloides Michx. Evolution. 33(3):
914-918; 1979.

Harniss, Roy 0.; Nelson, David L. A severe

epidemic of Marssonina leaf blight on quaking
aspen in northern Utah. Res. Pap. Ogden, UT:
U.S. Department of Agriculture, Forest Service,
Intermountain Forest and Range Experiment
Station; (In press).

McDonough, Walter T. Quaking aspen — seed

germination and early seedling growth. Res. Pap
INT-234. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain
Forest and Range Experiment Station; 1979. 13 p

Perala, Donald A. Aspen sucker production and
growth from outplanted root cuttings. Res. Note
NC-241. St. Paul, MN: U.S. Department of
Agriculture, Forest Service, North Central Forest
Experiment Station; 1978. 4 p.

Schier, George A. Seasonal variation in sucker
production from excised roots of Populus
tremuloides and the role of endogenous auxin.
Can. J. For. Res. 3(3): 459-461; 1973.

Schier, George A. Variation in suckering capacity
among and within lateral roots of an aspen clone.
Res. Note INT-241. Ogden, UT: U.S. Department of
Agriculture, Forest Service, Intermountain Forest
and Range Experiment Station; 1978a. 7 p.

Schier, George A. Vegetative propagation of Rocky
Mountain aspen. Gen. Tech. Rep. INT-44. Ogden,
UT: U.S. Department of Agriculture, Forest
Service, Intermountain Forest and Range
Experiment Station; 1978b. 13 p.

Schier, George A. Sucker regeneration in some
deteriorating Utah aspen stands: development of
independent root systems. Can. J. For. Res.
12(4): 1032-1035; 1982.

Schier, George A.; Campbell, Robert B. Effect of
cold storage on development of suckers on aspen
root cuttings. Res. Note INT-248. Ogden, UT:
U.S. Department of Agriculture, Forest Service,
Intermountain Forest and Range Experiment
Station; 1978. 8 p.

Schier, George A. ; Campbell, Robert B. Variation
among healthy and deteriorating aspen clones.
Res. Pap. INT-264. Ogden, UT: U.S. Department
of Agriculture, Forest Service, Intermountain
Forest and Range Experiment Station; 1980.
12 p.

Schreiner, Ernst J. Populus L. poplar. In:

Schopmeyer, C. S., tech. coord. Seeds of woody
plants in the United States. Agric. Handb . 450.
Washington, DC: U.S. Department of Agriculture,
Forest Service; 1974: 645-655.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT-168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

EFFECTS OF SOIL AMENDMENTS ON ASPEN SEEDLING PRODUCTION
James T. Fisher and Gregory A. Fancher

ABSTRACT: Quaking aspen (Populus tremuloides
Michx.) seedlings were grown in north central New
Mexico in a mountain valley nursery soil amended
with sulphur and one of four levels of peat moss
(0, 1/4, 1/2 and 3/4 peat (v/v) . The 1/4 peat
treatment is equivalent to 374 m /ha. Peat moss
improved soil medium physical and chemical
properties responsible for improving seedling
growth with each addition. Sulphur alone did not
produce satifactory seedlings. Peat-amended soil
produced plantable seedlings in one growing
season at the study site.

INTRODUCTION

The geographical range of quaking aspen (Populus
tremuloides Michx.) is enormous in western North
America; it spans over 40° latitude. More than
200,00 hectares are occupied in New Mexico,
Arizona, and the adjacent San Juan Basin (Jones
and Trujillo 1975) where aspen forests provide
numerous human benefits and renewable resources.

High on the list of potential benefits is the
role aspen can play in redirecting the course of
wildfire. In the southern Rockies, aspen has a
lower fire potential than conifer types and can
provide a critical fuelbreak. Flammability of
aspen has been estimated to be less than one half
that in adjacent conifers (Fechner and Barrows
1976) . This might explain why wildfires spread-
ing from high elevation conifer forests have been
observed to die out in aspen. Healthy stands of
aspen are regarded by fire managers as rela-
tively fire proof. It follows that maintenance
and establishment of aspen are useful fire
management practices, particularly in mountain
resort areas where ignition is likely and the
potential for loss of resource value and life is
great .

At present, land managers in the Southwest do not
possess a full understanding of the steps neces-
sary to grow aspen seedlings reliably and effi-
ciently, nor of those steps leading to fuelbreak
establishment. Through a U.S. Forest Service-
Eisenhower Consortium cooperative research pro-
ject begun in 1981, we are developing or refining
greenhouse, nursery, site preparation and weed
control practices leading to establishment of
aspen. This paper addresses bareroot seedling
production .

James T. Fisher is Associate Professor of Woody
Plant Physiology and Gregory A. Fancher is
Forest Research Specialist, Department of
Horticulture, New Mexico State University,
Las Cruces N. Mex.

Production of aspen seedlings from seed has
been largely ignored in the West until recent
years. However, large-scale production was
achieved more than one decade ago in the Great
Lakes region, notably at the Institute of Paper
Chemistry (IPC) , Appleton, Wisconsin (Benson
and Dubey 1972) . The methods developed by IPC
supplanted conventional nursery practices which
generally failed to avoid:

(1) rapid loss of seed viability in the seedbed

(2) washing of the seed

(3) drying of the surface soil during the first
two weeks

(4) damping-off during the seedling stage

The specific objective of this study was to
apply IPC methods at a northern New Mexico
mountain valley nursery site while testing soil
amendments potentially useful in reducing soil
pH and density. This refinement was believed
necessary to avoid seedling disease and nutri-
tional disorders, and to minimize nursery
lifting difficulties.

METHODS AND MATERIALS

The study was conducted at Mora Research Center
located in north central New Mexico at an
elevation of 2213 m. The frost free season is
100 to 120 days. Mean annual temperature is 6°C
and mean annual precipitation is about 51 cm.

The study site is a level valley bottom. Soil
is well-drained alluvium with moderate to slow
permeability. The upper 50 cm is a dark grayish
brown (10YR 4/2) sandy clay loam. According to
Cryer (1980) the soil profile classification is
Cumulic Haploboroll.

Aspen seed used in this study was collected in
early June, 1981, from open-pollinated clones
growing from 2500 to 2700 m elevation about 15
km northeast of Santa Fe , New Mexico. At the
time catkins were collected, seed release was
just beginning on a few branches of sampled
trees. Catkins were kept cool (18°C) during
and following transfer to a laboratory and
"cotton" was released and collected with a vacuum
after 20 days. Harder's (1970) extraction
procedure was used to remove "cotton" and minute
debris. Cottony hairs of the placenta remaining
attached to seeds can adversely affect germina-
tion (Myers and Fechner 1980) . Seed was bulked
and stored at -4° C over anhydrous calcium sulfate
("Drierite") in a sealed jar to maintain

seed viability (Benson and Harder 1972). Seed
germination was above 90 percent when tested
two weeks prior to nursery bed showing.

Installation of experimental nursery beds fol-
lowed procedures developed by Benson and Einsphar
(1962) and modified by Benson and Dubey (1972).
Within a 2.44 m x 15.9 m area, five 1.19 m x
2.41 m areas were excavated to a depth of 92 cm
for each to accomodate a 1.22 m x 2.44m x 2.44 m
wood frame supporting a hinged frame covered with
standard window screen. Plywood boards divided
each frame into equal quadrants to a depth of
92 cm. Polyethylene plastic lined the main frame
soil side walls to the same depth.

The excavated soil was combined with horticulture-
grade peat moss to establish four nursery bed
growing media: (1) soil; (2) 1/4 peat, 3/4 soil;
(3) 1/2 peat, 1/2 soil; and (4) 3/4 peat, 1/4
soil (by volume) . In addition, elemental sulfur
was added at the rate of 852 kg/ha (750 lb/ac) to
each treatment. Physical and chemical properties
of media were determined by routine soil test
procedures employed by the Soil and Water Testing
Laboratory, New Mexico State University.

Each bed frame was covered with plastic to
fumigate all experimental plots with methyl
bromide. The following day, frame tops were
lifted and the beds were aerated for 48 hours.

Aspen seeds were sown at the spacing recommended
by IPC (Benson and rjubey 1972) to produce 1 10—
160 seedlings per m . Following emergence,
excess seedlings were thinned. Beds were
irrigated daily by 1.8 cm bi-wall perforated drip
tubing. Fertilizer was applied via irrigation
water at the rate of 113 kg/ha N, 45 kg/ha P and
79.5 kg/ha K.

Treatments were randomized within frames. Within
a 30 cm x 91 cm area centered within each quad-
rant, 12 seedings were labeled in order to record
leaf number and height measurements, repeated at
two-week intervals. Seedling density for each of
three 30 cm x 30 cm subplots was recorded just
prior to harvest.

Seventeen weeks from sowing, seedlings were
lifted with a spade and enclosed in plastic bags.
Ten trees were harvested from each subplot.
Height, caliper, and fresh and oven dry weights
were recorded for each seedling. A portable leaf
area meter (Li-Cor, Inc.) was used to determine
leaf area for 12 of the 30 seedlings harvested
from each treatment. Analysis of variance,
Duncan's mean separation test, and multiple
linear regression were employed in da,ta analyses.

RESULTS

Peat additions progressively improved physical
and chemical properties of nursery bed media
(Table 1) . Most notable are improvements in soil
reaction, pore space, hydraulic conductivity, and
cation exchange capacity. Organic matter increa-
sed considerably but approached the recommended
level (3 percent) prior to any addition. In
the field, soil peat moss reduced surface
crusting and puddling compaction caused by
irrigation.

Table 1. Chemical and Physical Properties of Nursery Bed Media

SOIL 1/4 PEAT (v/v) 1/2 PEAT 3/4 PEAT

Hydraulic

Conductivity
(ml/cm - hr)

245.

Bulk Density
(g/cc)

.23

Pore Space
(% By Vol.)

82.

% Organic
Matter

15.

C.E.C.
(meq/lOOg)

39.0

Salts
(% Sol.)

0.8

N-Total (PPM)
(Kjeldahl)

894

1075

1160

2195

N03 (PPM)

42.9

P(PPM)

7.6

K(PPM)

29.8

* Before Addition of Sulfur.

Seedlings grown with peat amendments were consid-
erably taller and supported more leaves than
those grown in soil alone (figs. 1 and 2).
Seedling density averaged 132 per square meter
across all treatments and density differences
among treatments were not statistically signifi-
cant at the .05 level. Table 2 compares har-
vested seedlings across treatments. Most signi-
ficant is the failure of soil or soil and 1/4
peat to produce a minimum caliper of 0.3 cm
(1/8"). Only 3/4 peat produced a 30-cm shoot.
Reading across treatments in Table 2, differ-
ences for any paired numbers are statistically
significant at the .01 level except leaf areas
for 1/2 and 3/4 peat.

Multiple regression analysis of the pooled data
provided an opportunity for examining growth
relations of aspen seedlings. The correlation
matrix found in Table 3 shows several parameters

I \\ 1 1 1 1 1 1 1 1 1 1 1 1 1

6 8 10 12 11 IS

WEEKS FROM SEED

Figure 1. Cumulative Height Growth for Quaking Aspen Seedlings Under
Nursery Bed Conditions

14- ■
13- ■
12- ■
II"
10 ■ ■

te if
in
m

% «f

7 +

2 •

_■

3
2
1

• 75«h PEAT

O 50°lo PEAT

■ 25°lo PEAT

□ SOIL

t 10

WEEKS FROM

12
SEED

Figure

2. Cumulative Leaf Number for Quaking Aspen Seedlings Under
Nursery bed conditions

Table 2. Seedling Growth Responses at 16 Weeks

SOIL

V, PEAT

V2PEAT

J/4 PEAT

Height (cm)

10.92

13.60

24.11

33.73

Callper(mm)

T.94

2.26

3.18

3.95

Leaf Number

5.77

6.73

8.52

1 1.00

Leaf Area (cm*)

21.88

30.29

49.32

50.16

Shoot DWT(g)

0.24

0.37

0.98

1.88

Root DWT(g)

0.11

0.22

0.57

0.99

Table 3. Correlation Matrix (R2)

Leaf Shoot Root Leaf
Height Caliper No. DWT DWT Area

Height
Caliper
Leaf No.
Shoot DWT
Root DWT
Leaf Area

.86

.74
.68

.81
.76
.63

.67 .22

.71 .25

.52 .23

.78 .12

-- .12

to be closely related. Specifically, height is
closely related to caliper, leaf number, and
shoot weight. All of the values shown are
statistically significant (.0001 level).

The relative importance of physical and chemical
conditions derived from peat were not determined.
However, seedlings grown in peat-amended media
were subjected to conditions more favorable than
soil for nutrient exchange and uptake, and less
favorable for build up of soil pathogens.

Applied over an extensive area, peat amendments
would be costly and a local substitute might be
sought. In northern New Mexico old composted
sawdust can be obtained and may provide a satis-
factory substitute (Montano and others 1977) .
The disadvantages of fresh sawdust and farm
yard manure were discussed by Armson and
Sadreika (1974), who also recommended peat
application rates and procedures.

PUBLICATIONS CITED

Armson, K. A. and V. Sadreika. 1974. Forest tree
nursery soil management and related practices.
Can. Ministry of Natural Resources. 177 p.

Benson, M. K. and D. Dubey. 1972. Aspen seedling
production in a commercial nursery. Inst. Pap.
Chem. Genet, and Physiol. Notes No. 12, 7 p.

Benson, M. K. and Einsphar. 1962. Improved
method for nursery production of quaking aspen
seedlings. Tree Planters' Notes No. 53:11-14.

Benson, M. K. and M. L. Harder. 1972. Storage
of aspen seed. Inst. Pap. Chem. Genet, and
Physiol. Notes No. 11,4 p.

Cryer, D. H. 1980. Soil analysis: A method to
determine Christmas tree productivity in the
mountain valleys of Mora County. M.S. Thesis,
New Mexico State Univ., Las Cruces. 110 p.

Harder, M. L. 1970. Procedures for collection
and extraction of Populus seed. Inst. Paper
Chem. Genet, and Physiol. Notes No. 9:3 p.

Jones, J. R. and D. P. Trujillo. 1975. Develop-
ment of some young aspen stands in Arizona.
USDA For. Serv. Res. Pap. RM-151,11 p.

Montano, J. M. J. T. Fisher and D. J. Cotter.
1977. Sawdust for growing containerized forest
tree seedlings. Tree Planters' Notes 28:6-9.

Myers, J. F. and G. H. Fechner. 1980. Seed
hairs and seed germination in Populus . Tree
Planters' Notes 31:3-4.

DISCUSSION AND CONCLUSIONS

The study demonstrated that plantable aspen
seedlings can be successfully grown at the Mora
Valley nursery site if the soil is amended with
peat and sulphur. If the desired caliper is 0.3
to 0.9 cm (1/8" to 3/8"), 1/2 to 3/4 of the
nursery medium must be peat if seedlings are
grown and harvested in less than 110 days. In
the Mora Valley, it would be possible to plant
earlier, however, and this would result in larger
seedlings. Allowed an additional three weeks,
seedlings grown in 1/2 peat may reach desired
dimensions .

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT- 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

GROWTH OF AUSTRIAN PINE AND NORWAY SPRUCE

SEEDLINGS IN MINI-CONTAINERS
Houchang Khatamian and Fahed A. Al-Mana

ABSTRACT: Austrian pine (Pinus nigra Arnold) and
Norway spruce (Picea abies (L.) Karst.) were
seeded in selected mini-containers filled with
Jiffy Mix and placed in a greenhouse eighteen
weeks from germination. The stem length of both
species was greatest in Book Tinus; intermediate
in Book Hillson, Square Container and Tar Paper;
smallest in Leach Tube, Styroblock 8 and Styro-
block 7. The shoot and root dry weight of spruce
were greater in smaller containers. Pine seedlings
grew equally well in all containers. The ratio of
the root dry weight /container volume (mg/cm^) of
both species was higher in the smaller containers.

INTRODUCTION

In recent years, there has been a gradual shift
from field-grown, bare-root nursery stock to
container production. The increased use of
containerized seedlings in nursery and forestry
production is due to the advantages of better
plant survival and growth, extension of the plant-
ing season, and adaptability to mechanical planting.
Growth of tree seedlings in mini-containers under
controlled-environment conditions has been studied
by various workers (Arnott 1974; Barnett 1982;
Johnson 1975) . Generally, there are three cate-
gories of containers used in forestry and ornametal
plant production: tube, block, and plug (Barnett
1982) . A containerized seedling has a root system
which holds the growing medium when removed from
the container, and when planted the roots make
immediate contact with the soil (Mann 1977) .
Easy plug extraction depends upon the proper
development of the root system, media, moisture
content of the plug and the construction of the
container walls and ridges (Tinus 1978) . Usually,
four to five months is needed to produce gro-plug
seedlings with root systems suitable for trans-
planting into larger containers or the field, or
for sale (Mann 1977; Thomas 1980).

Contribution Xo. 83-265-J, Department of Horti-
culture, Kansas Agricultural Experiment Station.

Houchang Khatamian is associate professor of
Ornamental Horticulture at Kansas State Univer-
sity, Manhattan, KS.

Fahed A. Al-Mana is presently assistant professor
of Plant Production at King Saud University,
Riyadh, Saudi Arabia.

The design and shape of the nursery containers have
been improved recently. Some mini-containers now
have vertical ribs or grooves along the container
wall with drainage holes at the bottom. The ribs
are intended to direct the roots downward and
therefore prevent circling of roots (Dickenson and
Whit comb 1978; Tinus and McDonald 1979).

Research has shown that container volume and
diameter influence plant growth, and there is a
minimum volume below which growth is limited
(Wall and Whitcomb 1980) . In one study (Venator
and Rodriguez 1977) , the shoot and root growth of
Pinus caribaea var. hondurensis was influenced by
the cavity sizes of Styroblock 4 and 8. Similar
results were noted for lodgepole pine and white
spruce (Carlson and Endean 1976; Endean and
Carlson 1975) .

Seedlings produced in uniform size mini-containers
are adaptable to mechanized planting. The produc-
tion cost of the containerized seedlings may be
higher than field-grown ones, but compensations
include faster and superior growth, higher produc-
tion, longer planting periods and lower labor
and land costs. The purpose of this research was
to evaluate the effectiveness of selected mini-
containers on the rate of seedling growth.

MATERIALS AND METHODS

Austrian pine (Pinus nigra Arnold) and Norway
spruce (Picea abies (L . ) Karst.) were grown in
selected mini-containers to evaluate their effects
on seedling growth (table 1) . All containers were
filled with Jiffy-Mix (commercially available
peat-vermiculite 1:1 mix) and placed on wire
benches in a glass greenhouse. Four seeds were
placed in each cavity. At two weeks after germin-
ation seedlings were thinned to one per cavity and
at three weeks seedlings were fertilized with
liquid 20 N -8.6 P -16.6 K (100 ppm N) once a
week and watered every two to three days as needed.
The pH of the water was maintained between 5.0-5.5
using phosphoric acid (Tinus and McDonald 1979) .
The pH and Electrical Conductivity (EC) of the
growing medium were monitored before and throughout
the trial. Plants were grown for 18 weeks from
March to August, 1981, with average day and night
temperatures of 30° and 18°C, respectively.

Table 1. Container/cavity dimensions

Container Type Composition Top Diam. Length Width Depth Volume

(cm) (cm) (cm) (cm) (cm3)

Styroblock 7"
Styroblock^8
Leach Tube ,
Book Hillson
Book Tinus
Square Bottomless
Cylinder Tar Paper

Styrof oam

3.0

22.5

121.3

Styrof oam

3.8

15.0

131.1

Polyethylene

3.8

13.5

131.1

Polyethylene

3.8

12.5

172.1

Polyethylene

3.8

18.1

352.4

Unknown plastic

18.9

302.4

Asphalt

6.2

18.9

570.8

Containers referred to in text as small are, Styroblock 7, Styrobloc, 8, and Leach Tube.
Containers referred to in text as large are, Book Hillson, Book Tinus, Square Bottomless and
Cylinder Tar Paper.

2Styroblock 7 and 8-Silvaseed Company, P. 0. Box 118, Roy, Washington 98580.

3Leach Tube — Ray Leach Cone-Tainer, 15 — N. Maple Street, Canby, Oregon 97013.

4Book Hillson adn Book Tinus — Spencer — Lemaire Industries LTD., 11413-120 Street, Edmonton,

Alberta, Canada T5G 2Y3.

At the eighteeenth week, the plants were harvested.
The development of the root system in each container
was visually evaluated. The plant shoots and roots
were dried at 65°C for 48 hours for dry weight
determination. The experimental design was a
split plot in a random block with seven containers
and two species replicated four times. The growth
rate measurements were determined randomly by
selecting six plant samples' from each container
and species .

RESULTS AND DISCUSSION
Stem Length

Larger containers such as Book Tinus and Tar Paper
produced greater stem length for Austrian pine and
Norway spruce when compared with the small size
cavities of Styroblock 7 (table 2) . Possibly the
larger diameter of these containers influenced the
plant stem length. Similar results were reported
for the lodgepole pine and white spruce (Carlson
and Endean 1976; Endean and Carlson 1975). Wall
and Whitcomb (1980) also reported an increase in
seedling height of Lacebark Elm, Atlas Cedar and
Japanese Black Pine.

Shoot and Root Dry Weight

With the exception of root dry weight in Tar Paper,
the shoot and root dry weights of pine were similar
in all containers tested (table 2) . Whereas the
greatest shoot dry weight of Norway spruce was
obtained in the small and tapered containers.
According to Endean and Carlson (1975) , container
configuration (height or diameter) had no effect
on shoot dry weight or the shoot length of lodge-
pole pine seedlings, but it did on white spruce
seedling growth. It appears that lodgepole pine
and white spruce respond differently to contain-
erized conditions (Carlson and Endean 1976) .
Spruce is a more shallowly rooted species than

pine and therefore had a greater number of roots
in the top quarter of the container. In contrast,
pine had more roots in the bottom of the container.
Austrian pine grew equally well in all containers
tested regardless of container configuration and
volume. However, Norway spruce seems to grow
better in the smaller and tapered containers such
as Styroblock 7, Styroblock 8, and Leach Tube,
possibly because of its shallow root system.

Shoot/Root Ratio

The shoot/root dry weight ratio of pine seedlings
was greatest in Tar Paper which gave the smallest
root system (table 2) . The Tar Paper was formed
as a cylinder which had smooth walls and no ribs.
Circulating and spiralling primary lateral roots
about the tap root is common in cylindrical con-
tainers (Tinus 1978 and Agnew 1981) . The main
disadvantage observed with the Tar Paper container
was the root penetration through the tar paper wall
into the adjacent tar paper pots. This makes pot
removal difficult, damages the root system and
results in loss of roots. This is likely the
reason for lower root dry weight of both species
grown in Tar Paper containers. Such problems with
Tar Paper containers also were noted by Strachan
(1974). Norway spruce had a greater shoot/root dry
weight ratio in the larger volume containers: Tar
Paper, Book Tinus and Book Hillson (table 2).

Root Quality

The extensity , f ibrousness , and uniformity of the
root system were taken into consideration when
visual evaluations on root quality were made.
Austrian pine produced a very good root system in
all containers tested except for Tar Paper. The
root system of spruce was good in Leach Tube,
Styroblock 8 and Styroblock 7 (table 2) . The plugs
of both species indicated a more fibrous and dense
root system in Leach Tube and Styroblock containers
(fig. 1). The Book planters produced plugs that
were quickly and easily extracted (figs. 2 and 3).

Table 2. Effect of

various containers on stem

length (cm) , dry weight

(g) , root

quality and root

dry weight/container

volume ratio (m

g/cm ) of Austrian pine

and Norway

spruce seedlings.

Container

Stem

Drv 1

height (g)

Root
_ , . X

Root Dry Weight/

Length

Qualxty

Container Volume

(cm)

Shoot

Root Ratio

Ratio (mg/cm)

Austrian Pine

Styroblock 7

4.3c7

0.92a

0.36ab 2.55c

4.2ab

3.0a

Styroblock 8

4 . 6bc

1.19a

0.44a 2.70c

4.5a

3.3a

Leach Tube

4.5bc

1.05a

0.39ab 2.69c

4.3a

3.0a

Book Hillson

5 .Oab

1 . 11a

0.34ab 3.26b

4. Oab

2.0b

Book Tinus

5.2a

1.21a

U.41a z.95bc

3 . 9ab

1 . 2c

Square Bottomless

4 . 7abc

1.24a

0.41a 3.02bc

4.4a

1.4c

Cylinder Tar Paper

4.8ab

1.23a

0.27b 4.55a

3 . 4b

0 . 5d

Norway Spruce

Styroblock 7

2.8c

0.30ab

0.18ab 1.66bc

3.4ab

1.5a

Styroblock 8

3.0bc

0.32a

0.20a 1.60bc

3.7a

1.5a

Leach Tube

3.0bc

0.27abc

0.19a 1.42c

3.7c

1.5a

Book Hillson

3.1b

0.22cd

0.09c 2.44a

2.1c

0.5b

Book Tinus

3.5a

0.19d

0.09c 2.11ab

2.0c

0.3b

Square Bottomless

3.0bc

0.23bcd

0.14abc 1.64bc

2.8abc

0.5b

Cylinder Tar Paper

3.4a

0.25abcd

0.12bc 2.08ab

2.5bc

0. 2b

Means of 24 seedlings from 4

replicates .

^Mean separation in

columns by Ducan's multipl

e range test, 5% level.

xVisual rating of root system;

1 = poor, 2 - fair, 3 = good, 4 = very

good, 5 =

excellent .

Figure 1. Austrian pine (A) and Norway spruce (B) Figure 2. Austrian pine seedlings grown in Book

plugs extracted from Styroblock 7, Styroblock 8, Hillson which can be easily opened to observe the

and Leach Tube. root system.

Book (#f //**»)

060* (Tt'»*r)

Figure 3. Austrian pine plugs extracted from Book
Tinus and Book Hillson. Norway spruce plug of Book
Hillson .

The square containers were effective for the produc-
tion of a good root system in both species (fig. 4).

The smaller and tapered containers produced a more
dense root system than the large container by the
eighteenth week post-germination. It has been
suggested (Allison 1974 and Sjoberg 1974) that the
tapered cavity design with rigid and ribbed walls
of RL single seedling container (Leach Tube) , or
the Styroblocks, influences the root growth resulting
in fibrous well-developed and balanced root system.
Barnett (1982) showed that pine seedlings grown in
Styroblocks performed better than those grown in
other containers.

CONCLUSION

Selection of containers should be based on the
preference of a particular plant species. Smaller
and tapered containers such as the Styroblock 7,
Styroblock 8 and Leach Tube can be used to grow
pine, spruce or similar plant seedlings over shorter
periods of up to six months. The larger containers
such as the Book and Square may be used successfully
over a longer period. Many studies have focused on
the effect of container shape and configuration on
plant growth, but yet it is not known whether the
actual material which containers are made of has
any influence on root development and growth.
Effects of various types of mini-containers on the
seedling performance after transplanting need further
research .

PUBLICATIONS CITED

Agnew, M. L. Influence of plexiglass inserts on
prevention of root spiraling of container grown
tree species. Master's Thesis, Department of
Horticulture, Kansas State University, Manhattan,
Kansas. 1981.

Figure 4. Austrian pine and Norway spruce grown
in square bottomless container.

Allison, C. J. Jr. Design consideration for the RL
single cell system. Proc. N. Amer. Containerized
For. Tree Seedling Symp . , Great Plains Agric.
Counc. Publ. 68:233-236; 1974.

Arnott, J. T. Performance in British Columbia.

Proc. N. Amer. Containerized For. Tree Seedling
Symp., Great Plains Agric. Counc. Publ. 68:283-
290; 1974.

Barnett, J. P. Growing containerized Southern pines.
Proc. N. Amer. Containerized For. Tree Seedling
Symp., Great Plains Agric. Counc. Publ. 68:124-
128; 1974.

Barnett, J. P. Selecting containers for southern
pine seedling production. P. 15-24. In R. W.
Guldin and J. P. Barnett (eds.) Proceedings of
the Southern Containerized Forest Tree Conference.
Savannah, Georgia; 1982.

Carlson, L. W. , and F. Endean. The effect of rooting
volume and container configuration on the early
growth of white spruce seedlings. Can. J. For.
Res. 6:221-224; 1976.

Dickenson, S. and C. E. Whitcomb. Effect of con-
tainer design on root quality. Res. Rpt., P-777,
Agric. Exp. Sta., O.S.U. P. 35-36; 1978.

Endean, F. and L. W. Carlson. The effect of rooting
volume on the early growth of lodgepole pine
seedlings. Can. J. For. Res. 5 : 55-60 ; 1975 .

Johnson, H. J. Canadian forestry service container
planting trials in Alberta, Saskatchewan, and
Manitoba. Proc. N. Amer. Containerized For. Tree
Seedling Symp., Great Plains Agric. Counc. Publ.
68:298-305; 1974.

Mann, W. F., Jr. Status and outlook of container-
ization in the South. J. For. 75:579-581; 1977.

Sjoberg, N. E. The Styroblock container system.
Proc. N. Amer. Containerized For. Tree Seedling
Svmp . , Great Plains Agric. Counc. Publ. 68:217-
228; 1974.

Strachan, M. D. Tar paper container. Proc. N.
Amer. Containerized For. Tree Seedling Symp . ,
Great Plains Agric. Counc. Publ. 68:209-210;
1974.

Thomas, S. P., Jr. Gro-plug systems and their
practical application in growing ornamentals.
Proc. Int. Plant. Prop. Soc. 30:312-318; 1980.

Tinus, R. W. Root system configuration is important
to long tree life. Proc. Int. Plant. Prop. Soc.
28:58-64; 1978.

Tinus, R. W. and S. E. McDonald. How to grow tree
seedlings in containers in greenhouses. Rocky
Mountain Forest and Range Experiment Station,
USDA Forest Service, Bottineau, N. Dak. , 256
p.; 1979.

Venator, C. R. and A. Rodriguez. Using styroblock
containers to grow Pinus caribeau var.
hondurensis Borr. of golf, nursery seedlings.
Turriabla 27 (4) : 393-396 ; 1977.

Wall, S. and C. E. Whitcomb. A comparison of

commercial containers for growing tree seedlings.
Res. Rpt. P-803, Agric. Exp. Sta. , O.S.U.,
P. 72-75; 1980.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT- 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

*>\-2>o\A

EQUIPMENT FOR REVEGETATING DISTURBED LANDS
Richard G. Hallman

ABSTRACT: Federal land managers find themselves
caught between new mining laws that require
complete restoration and the difficulty of
establishing plant growth in the arid area where
mining is occurring. The Bureau of Land
Management funded the Forest Service Missoula
Equipment Development Center to develop equipment
for revegetation. Six equipment systems were
developed.

INTRODUCTION

When surface mining for coal in the West began in
earnest, about 10 years ago, it became apparent
that many techniques developed over the years for
improving range habitat were unsuited to revegetate
mined land. Surface mining mixes soil profiles,
alters surface and ground hydrology, and removes
all vegetation. Clearly, new equipment and
techniques were needed to restore this land.

The Bureau of Land Management (BLM) of the
Department of the Interior (USDI) was the logical
Government agency to tackle the problem. About
80 percent of strippable coal in the West is
Federally owned, and the BLM manages most of the
land where the coal is found. The BLM, along
with the Office of Surface Mining, another USDI
agency, is responsible for determining the
revegetation potential of these lands.

Federal and State mining laws require that
restored vegetation equal what existed before
mining. Fortunately, coal seams in the West often
are thick; seams of 20 feet and more are not
unusual. So revenue from mining deposits of
that magnitude makes it economically feasible for
operators to do the revegetation job that is
required.

As part of its effort to develop new revegetation
techniques, the BLM turned to the USDA Forest
Service Missoula Equipment Development Center
(MEDC) . MEDC and its sister Center at San Dimas ,
Calif., were the only equipment development
organizations involved in rangeland improvement
activities .

In 1975 MEDC personnel began working with the BLM
to develop equipment and techniques to revegetate
lands under arid and semiarid conditions where
establishing vegetation is difficult and
expensive. Six pieces of equipment were
eventually built to accomplish six specific
revegetation tasks. Each piece of equipment is
described in the following text. The six
equipment systems currently are being evaluated
in various locations in the West to perfect the
techniques and to establish cost data. For
additional information, write USDA Forest Service,
Missoula Equipment Development Center, Fort
Missoula, Missoula, MT 59801.

DRYLAND PLUG PLANTER
Function

The dryland plug planter (fig. 1) is designed to
automatically plant containerized trees and shrub
stock on surface-mined reclaimed sites. To
insure survival on semiarid sites, the root
systems must stay in contact with soil moisture.
To help accomplish this, the planter is able to
plant containerized stock seedlings that are up
to 61 cm long.

Richard G. Hallman is a Forester and Program
Planner in the Resource Management Program at the
Missoula Equipment Development Center, USDA
Forest Service, Missoula, Mont.

Figure 1. — Dryland plug planter plants large
container stock; large stock imp roves survival
chances .

Description

The dryland planter is designed to be mounted on
the rear of a tractor. It features hydraulic
leveling devices, hydraulic auger with a
scarifier, rotating carousel mounted on a movable
carriage and two packing spades. The machine
plants containerized shrubs or trees quickly and
effectively. The leveling devices and high
clearance enable operations on rough ground or
moderate slopes, while insuring adequate place-
ment. The containerized root system and auger
holes allow sufficient moisture uptake and
unrestricted root growth for better survival.

The planting is automatic and controlled from
the tractor. When the planter is positioned,
the platform is leveled with hydraulic cylinders.
The auger digs a hole; the scarifier auger then
removes any competing vegetation from around the
hole. The carousel containing the seedlings
rotates and the carriage moves forward on the
platform, dropping a seedling into the hole.
The packing spades firm the soil around the
seedling. Planting rate is estimated at more
than one per minute .

Specifications

Carousel capacity: 24 seedlings
Auger diameter: 7.6 to 12.7 cm

46 cm scarifier
Depth: 61 to 76 cm

Power requirements (drawbar) : 52 to 75 kW

greatly reduces overall transplanting costs by
reducing the transport time required for each
tree. Up to 24 trees per day can be transplanted
with the tree transport trailer system. The
front-end loader-mounted tree spade is very
maneuverable and can negotiate slopes up to
20 percent.

Description

The system consists of a Vermeer Model TS-44A
Tree Spade mounted on an Owatonna 880 articulated
front-end loader and a specially built trailer
consisting of two rows of four cone-shaped pods.
The pods are 112 cm in diameter and 108 cm deep.

Eight soil plugs are removed from the transplant
site, loaded into the trailer, and transported
to the transplant supply area. They are then
replaced in the trailer with selected trees
and shrubs that are transported back to the
transplant site and planted. The front-end
loader-mounted tree spade digs the trees or
plugs, places them in the trailer pods, and
tows the trailer between the transplant site
and transplant supply area.

Specifications — Trailer

Overall width: 2.4 m with walkway removed
Height: 2.1 m
Weight: 2,722 kg

Capacity: 8 trees or plugs or 3,922 kg
Cone size: 112 cm diameter, 109 cm deep
Power requirements : 60 kW recommended

TREE TRANSPLANTER
Function

The tree transplanter system (fig. 2) was
designed to transplant small trees and large
shrubs that grow naturally around the mining
site to the revegetation area. The trailer is
an important part of the system because it

Specifications — Tree Transplanter

Ball (cone) depth: 46 to 152 cm
Tree size: to 25 cm diameter (maximum
tree size may vary with the
type of root structure)
Mounting: tractors, trailers, truck or
front-end loaders

DRYLAND SODDER

Description

Function

The dryland sodder (fig. 3) transfers native
topsoil from the mine area to the reclamation
area with its structure, profile, and vegetation
intact. Reclamation is greatly enhanced because
the soil horizons are not mixed, so soil develop-
ment does not have to be repeated.

The dryland sodder strips the top layer of soil
and vegetation (sod, f orbs , shrubs, and small
trees) from areas to be surface mined and places
it intact over reshaped areas. The soil layer
is scooped into the sodder and transported to
the reclamation area. It is removed by tilting
and shaking the bucket while slowly moving the
loader backward. The conveyer system will
feature hydraulic control of the conveyor rollers,
allowing the sod to be removed without tilting
the bucket.

The dryland sodder is a modified front-end loader
bucket. The side walls and back wall are
vertical to minimize damage to shrubs and tree
seedlings that are stripped along with the soil
and sod. The wide, flat bottom of this bucket
is sprayed with plastic to reduce friction. A
conveyor system is being developed for the bottom
of the dryland sodder to aid loading and unload-
ing of the sod strips and to prevent excess soil
separation during the transfer.

Specifications

Width: 4.3m
Length: 2.4 m
Depth: to 30 cm

Power requirements (flywheel) 80 to 391 kW

SPRIGGER

BASIN BLADE

Function

The sprigger (fig. 4) undercuts and gathers
sprigs, or portions of rhizomatous stems, that
can produce roots and shoots. The harvested
sprigs are then spread out on the area to be
revegetated and covered with soil .

Description

The sprigger is a modified potato harvester. It
consists of an undercutting blade and a pair of
wide, inclined conveyors. The conveyors are
long rods attached between two chains and spaced
3.8 cm apart. A third conveyor across the top
of the machine moves the harvested material to
the side where it is dumped into a truck or
piled in windrows. The sprigger is towed and
powered by a tractor.

After the shrubs are mowed, the sprigger is
pulled through the stand, cutting the roots
well below the ground surface. The cutting
action lifts the soil and shrubs onto the
conveyors. The soil is shaken loose and falls
through the spaces in the conveyors to the
ground. The bareroot rhizomatous shrubs, or
sprigs / are gathered and carefully planted
on the reclamation area.

Specif ications

Width: 1.5 m
Depth: 30 cm

Power requirements (drawbar) : 60 to 75 kW

Figure 4. — Sprigger digs up rhizomatous material
for planting on reclaimed areas .

Function

The basin blade (fig. 5) scoops out large basins
or depressions along slopes. Moisture accumu-
lates in these basins to provide a favorable
microsite for plant growth. The large basins
reduce wind erosion. They also provide the
advantages of terracing with fewer hazards and
less expense. They collect runoff and trap snow
and blowing topsoil. The furrows formed by the
scarifying teeth help retain broadcast seed and
fertilizer and promote increased infiltration.

Description

The basin blade is a large, crescent-shaped,
heavy steel blade mounted on the rear of a
crawler tractor . The blade is mounted on a
parallelogram multiple -ripper shank. It is
raised, lowered, and tilted hydraulically .
Several replaceable scarifying teeth are
located along the bottom edge of the blade.

The tractor is driven along the contour of a
slope and the blade is periodically raised and
lowered to form large depressions. Seed is then
broadcast along the slope.

Specifications

Width: 3 m
Depth: to 91 cm

Power requirements (flywheel) 216 to 276 kW

Figure 5. — Basin blade makes depressions in
soil that trap moisture, creating favorable
conditions for plant growth.

HODDER GOUGER

Function

The gouger (fig. 6) creates numerous depressions
in the soil surface. These depressions provide
a suitable microclimate for plant establishment
by increasing moisture availability, reducing
wind and water erosion, and providing shade.

Description

The gouger consists of three to five semicircular
heavy steel blades attached to solid arms. Each
blade has three scarifying teeth along the bottom
edge. The arms are attached to a heavy-duty
frame with spring-loading mechanisms. They may
be mounted in either one- or two-row configura-
tions. The frame is supported with side wheels
that are periodically raised and lowered to allow
the blades to scoop out depressions. The unit is
operated hydraulically and features positive
depth control and automatic up and down cycling.
A seedbox spreader is mounted on the rear of the
machine to broadcast seed into the depressions.

The gouger is towed behind a tractor. The
hydraulically powered automatic cycling system
moves the frame up and down in relation to the
wheels to create depressions. The depth of the
depressions, cycle rate, and blade configuration
can be varied to suit the site conditions.
Average production rates have varied from 1 to
1.1 ha per hour .

The gouger creates more and larger depressions
than similar equipment. The automatic cycling
and hydraulic depth control make it easier to
operate and the adjustable cycle rate and
variable blade configurations contribute to its
versatility. The spring-loaded blade arms enable
it to operate in fairly rocky ground.

Specifications

Implement width: 3.4 m

Depression width: 38 to 56 cm

Depression length: 0.9 to 1.2 m

Depth: 15 to 25 cm recommended

Power requirements (drawbar) : 37 kW minimum

Figure 6. — Hodder gouger makes depressions in soil and simultaneously seeds
area to establish plant cover.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT- 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

PRELIMINARY TRIALS ON UPGRADING PLATANUS OCCIDENTALIS
WITH THE HELMUTH ELECTROSTATIC SEED SEPARATOR
Robert P. Karrfalt and Richard E. Helmuth

ABSTRACT: The electrostatic seed separator is a
recently invented seed conditioning machine which
uses the force of an electrostatic field to
separate particles of different area and weight.
It has been successfully used to size, clean,
and improve germination of P latanus occidenta 1 i s
seed. The seed separator also should be useful
on other tree seed.

INTRODUCTION

Upgrading refers to steps that exceed basic
cleaning which improve the quality of seed.
Therefore, upgrading includes removing empty
seed, fungus or insect damaged seed, and stones
or pitch. Sizing seed can also be considered
upgrading because speed of germination can vary
for different seed sizes. Several authors have
stressed the importance of upgrading and how
to accomplish it (Belcher 1978; Bonner 1978).

Sycamore ( P latanus occidenta 1 is L.) seed is gen-
erally low in viability and difficult to upgrade
because of its small size. The electrostatic
seed separator was tested on sycamore to deter-
mine how it might resolve this problem.

Principles of Electrostatic Separator

An elementary demonstration of the electrostatic
movement of particles includes lifting particles
of paper with a piece of plastic that has been
charged by rubbing it with a dry cloth. The
paper is drawn to the plastic by an electrostatic
field. Heavier seed can be separated from lighter
seed by the same principle if the strength and
design of the electrostatic field is carefully
contro 1 led .

Robert P. Karrfalt is Seed Processing Specialist,
USDA Forest Service, Southeastern Region, National
Tree Seed Laboratory, Dry Branch, Ga.

Richard E. Helmuth is inventor of the electro-
static seed separator and President of the Helmuth
Corporation, Carmel, Ind.

Mention of trade names is only to identify
equipment used and does not imply endorsement by
the U.S. Department of Agriculture. U.S. patents
have been granted on this equipment.

The Helmuth electrostatic seed separator
consists of a hanging electrode and adjustable
ground plates (fig. 1) Voltage applied to the
stationary electrode creates an electrostatic
field between the electrode and the ground. As
seed is poured between the ground and the elec-
trode by the vibratory feeder, the static field
carries the lighter seed and impurities towards
the ground. The stronger the static field, the
farther the particles will be pulled. The
strength of the field is controlled by adjusting
the voltage applied to the electrode. For each
seed lot, there is a voltage that produces a max-
imum distance between the lightest and heaviest
seeds being separated. This voltage must be
determined by trial during processing just like
adjusting other seed conditioning equipment.
Using a voltage higher than the one producing
the maximum speed will only move all the seeds
closer to the movable ground and not give any
better separation. The purpose of the ground's
mobility is to adjust the distance so the seed
can separate. When the seeds have reached the
bottom of the static field, they are collected
in a tray. Adjustable vanes in the collection
tray keep the fractions separated.

Figure 1. — Diagram of the electrostatic seed
separator .

MATERIALS AND METHODS

RESULTS AND DISCUSSION

One lot of sycamore was rough cleaned on a
Clipper office tester using a 5/64 x 3/4
slotted screen on top and a number 7 round hole
screen on the bottom. This removed the bulk of
the fluff which prevented the seed from flowing
freely. A portion of seed was taken from the
tester and designated as the original sample.
This original lot was upgraded on the Helmuth
electrostatic separator. The electrode is
80 cm x 130 cm. Voltage can vary from 0 to
120,000 volts to accomodate many particle sizes.
The voltage setting and feed rate established
by preliminary trials and x-ray analysis will
determine full seed percentages. Although
voltages are high, no danger can occur to the
operator if the machine is used properly.

After the preliminary trials, six fractions
were obtained from the original lot. Each
fraction was evaluated for germination,
Czabator's germination value (Czabator 1962),
purity, full seed percentage, and seed per
pound. Tests were conducted according to the
Association of Official Seed Analysts' rules.
Stratification was for 60 days at 3 C on the
germination media. Germination was on crepe
cellulose pager with a temperature of 20 C at
night and 30 C during the 8 hour day. Ger-
mination counts were made daily; the final
count was made on day 12. There was no
statistical analysis. Table 1 presents the
data .

Table 1. — Seed test results of the original seed lot and the six samples obtained by electrostatic seed
separation. Values are based on actual germination data.

FRACTION #

ORIGINAL

ACTUAL
GERMINATION

GERMINATION
VALUE

8.23

22.

16.65

18.

,94

15.

,92

13 .28

7 .05

PERCENT
FULL SEED

SEED PER
POUND (M)

147.0

94.

99.0

101 .

118.

152.2

168.0

PURITY

100

DAYS TO REACH
907c OF TOTAL
GERMINATION

Notable accomplishment was made with all seed
quality measurements. The results are summarized
in table 1. Purity was improved from 88 to 99
percent or better, and full seed percentage from
34 to a maximum of 52. The larger seed are
almost twice as big as the smaller seed. The
best germination was 18 percent better than the
original lot. The largest three sizes of seed
were also the most vigorous as shown by their
sizeable germination values.

The improvement in viability and vigor is best
understood by examining the data on a full seed
basis (table 2). The pattern in germination
is substantially modified. Instead of the best
lot germinating 25 percent higher than the poor-
est lot, it is only 7 percent better on a full
seed basis. The computed germination value,
using full seed data, is actually higher for the
smaller seed. This is because the smaller seed
reached 90 percent of their total germination
sooner than the larger seed. Therefore, the
higher full seed percentage of the best lots
is largely responsible for the better germination
and germination values.

Removal of empty seed was not, however, the only
effect of the seed separator. The fact that
the smaller seed germinated the fastest, shows
there were also physiological differences among
the seed sizes.

Table 2. — Germination and germination value computed on full seed basis.

FRACTION # ORTGINAL 1 2 3

GERMINATION

GERMINATION
VALUE

71 . "

82.15

78.66

88.58

100.75

96.46

95.58

According to the data obtained, the electro-
static separator appears to have definite
potential to effectively upgrade small tree seed.
Other species that might be effectively
upgraded would include birch, sweetgum and coni-
fers such as white spruce. In a preliminary
trial, redwood purity was visually much improved
with the Helmuth separator. There were no labor-
atory test data. In the nursery, the upgraded
seed will give more uniform germination and
provide more uniform seedling densities, greater
numbers of plantable seedlings per pound of
seed, and more efficient use of nursery space.

PUBLICATIONS CITED

Belcher, E. W. ; Karrfalt, R. P. The processing
of conifer seed. In: Proc. Small Lot Forest
Seed Processing Workshop; 1977, Oct. 18-20;
Atlanta, GA. USDA Forest Service, South-
eastern Area, pp 9-18. 1978.

Bonner, F. New developments in seed pro-
cessing. In: Proc. Small Lot Forest Seed
Processing Workshop; 1977, Oct 18-20;
Atlanta, GA. USDA Forest Service, South-
eastern Area, pp 19-23. 1978.

Czabator, F. J. Germination value: an index
combining speed and completeness of pine seed
germination. For. Sci. 8: 386-396; 1962.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT- 168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

SURVIVAL, GROWTH , AND ROOT FORM OF CONTAINERIZED JEFFREY PINES
TEN YEARS AFTER OUTPLANTING
J. D. Budy and E. L. Miller

ABSTRACT: To evaluate the effect of various con-
tainers on survival and growth, trials established
in 1973 were remeasured in 1983. In addition,
20 seedlings were excavated in order to determine
the effect of container type on root development.
After 10 years, the container type had a signifi-
cant effect on survival and height growth. Root
form and the number of lateral roots were also
influenced by container type.

INTRODUCTION

Since the early 1970 's, containerized seedling
systems have been developed and tested through-
out the United States. The early work was con-
cerned largely with the development of an accept-
able and suitable container. Early experimental
container types were available in various sizes,
shapes and materials. These containers were
either planted with the seedling or removed just
prior to planting. Over the past decade, evalu-
ation of the various containers has been based
on early field performance, production costs,
and technical problems.

The rapid evolution of container planting systems
both in Canada and the U.S. resulted in a tremen-
dous need to transmit research findings. Fortun-
ately, much of the information has been made
available through conference proceedings. In
1971, the Canadian Forestry Service sponsored
a workshop on container planting (Waldron 1972).
The first international conference held in Denver
brought together much of the knowledge and exper-
tise available on containerized seedlings (Tinus
and others 1974). Two symposia held in 1981,
the Southern Containerized Forest Tree Seedling
Conference (Guldin and Barnett 1982) and the
Canadian Containerized Tree Seedling Symposium
(Scarratt and others 1982), updated much of the
available information on containerized seedling
systems .

This research was supported by funds allocated
from the Mc I nt i re-Stenn i s Cooperative Forestry
Research Program.

Jerry D. Budy is Assistant Professor of Forestry,
Dept. of Range, Wildlife, and Forestry,
University of Nevada Reno. Elwood L. Miller is
Associate Dean of Resident Instruction, College
of Agriculture and Professor of Forestry, Dept.
of Range, Wildlife and Forestry, College of
Agriculture, University of Nevada Reno.

Although information has rapidly accumulated since
the early 1970' s, long term studies on growth
and development are lacking. The development
and evolution of containerized systems will be
influenced by biological performance under field
conditions. Considerable discussion has dealt
with the potential problem of root deformation
resulting from container designs. Although a
symposium was devoted to the root form of bare-
root and containerized seedlings (Van Eerden and
Kinghorn 1978), the overall effect of root con-
figuration on field performance is still not well
documented. The primary objective of this paper
is to report on ten year survival, growth, and
root form of containerized seedlings outplanted
on adverse sites.

METHODOLOGY

The materials and methods used in establishing
the original trial in 1973 are discussed in the
North American Containerized Forest Tree Seed-
ling Symposium (Miller and Budy 1974). Survival,
height, and root collar diameter were measured
in June 1983. Five seedlings of each container
type were excavated by hand in order to recover
the root system extending 30cm from the container.
No attempt was made to recover the entire root
system. After excavation, the number of lateral
roots extending from the container sidewalls was
recorded and the diameter of the tap root at the
bottom of the container was measured. The seed-
ling was severed at the root collar, and shoot
and root green weights were determined.

Containers

The container types included in the 1973 trial
and reevaluated in 1983 are described in Table
1. The Japanese paperpot is designated FH520.
The Conwed is an open-mesh, nonbiodegradable poly-
propylene plastic material. The Conwed desig-
nated as 9+3 in this paper contained 9-inches
of potting mix with 3-inches of the plastic mesh
left exposed above the soil surface when planted.
The Zeiset containers are made of a polyethelene
coated board stock paper, similar to that used
in milk cartons. The polyetheylene coating (.0005
inch) is intended to keep plants divided while
in the greenhouse, but not thick enough to girdle
plants when outplanted in the field.

Table 1. — Description of containers evaluated.

Dimensions

Container

: Dia.

: Depth

: Dia.

: Depth

Rootinq

Volume

Type

: (in)

: (cm)

: Material :

(inJ)

: (cmJ)

8-Paperpot

: 2.0

: 7.9

: 5.0

: 20.0

: Treated paper :

25.1

: 392.7

9+3- Con wed
12-Conwed

: 2.0
: 2.0

: 9.0
: 12.0

: 5.0
: 5.0

: 22.9
: 30.5

: Plastic mesh :
: Plastic mesh :

28.3
37.7

: 463.3
: 617.8

12-Zeiset

: 2.51

: 12.0

: 6.41

: 30.5

: Polyethylene cover - :
: ed cardboard :

75.0

: 1229.0

Side of square.

RESUCTS

Survival and Growth

After 10 years, the survival was very similar
to the first year survival (Table 2). Compared
to the losses encountered during the first year,
subsequent mortality was relatively low. The
highest survival and best growth after 10 years
were evident with the Conued containers. The
results indicated a highly significant differ-
ence (P < .01) in survival between the Conwed
containers and the paper and cardboard containers
After nine years the difference in heights was
apparent, but not significant. The significant
difference (P < .05) in height growth was not
revealed until after ten years. The seedlings
in Zeiset containers showed the lowest height
and diameter growth. The poor field performance
of the Zeiset seedlings appears to be related
to the root form and is discussed in the follow-
ing section.

Root Form

Excavation of the containerized seedlings revealed
that field performance may be largely affected
by the design and shape of the container. Repre-
sentative root systems after excavation are shown
for the 12-Conwed (Fig. 1), 9+3-Conwed (Fig. 2),
12-Zeiset (Fig. 3), and 8-Paperpot (Fig. 4). The
most obvious difference between the four container
types is the lack of lateral roots penetrating
from the Zeiset container.

The only container type which showed any signs
of breaking down was the Paperpot. The Zeiset
containers were still very much intact and it
appeared that the plastic coating was very effec-
tive in preventing lateral root development. The
Conwed containers were not expected to break down;
however, as the lateral roots developed they were
able to break apart the plastic mesh (Fig. 5).
Although the roots showed signs of constriction
(Fig. 6), the developing lateral roots can appar-
ently overcome the obstruction.

Table 2. — Mean survival, diameter and height of Jeffrey pine seedlings outplanted in 1973.

Container
Type

Survival 1
1974

Survival 1
1983

Diameter'
1983

Height1
1983

9+3-Conwed
12-Conwed
12-Zeiset
8-Paperpot

(?o)

80a
76h
50b

(as)

63a

61h

39h
34b

(cm)

3.3
3.1
2.3
2.5

xMeans with the same superscript are not significantly different.

(cm)

77
70
51
57

"Diameter at root collar.

Figure 1. — Root penetration of a Jeffrey pine
through a 12-Conwed ten years after outplanting.

Figure 2. — Root Penetration of a Jeffrey pine
through a 9+3-Conwed ten years after outplanting.

Characteristics of the excavated seedlings are
shown in Table 3. The Conwed seedlings had a
greater number of lateral roots penetrating
through the container sidewalls, a larger tap
root emerging from the bottom of the container,
and a greater biomass than the Zeiset and Paper-
pot seedlings. There was a highly significant
difference (P < .01) in the mean number of lateral
roots between the Conwed and both the Zeiset and
Paperpot seedlings (Table 3). Also, the Paperpot
seedlings had significantly (P < .01) greater
root penetration through the sidewalls than the
Zeiset seedlings. The lack of lateral root pene-
tration for the Zeiset seedlings may account for

Figure 3. — Root penetration of a Jeffrey pine
through a 12-Zeiset ten years after outplanting.

)

Figure 4. — Root penetration of a Jeffrey pine
through a 8-Paperpot ten years after outplanting.

the poor field performance. In addition, after
the containers were removed from the excavated
seedlings (Fig. 7-10), root problems were most
evident on the Zeiset seedlings. Although the
Zeiset seedlings developed lateral roots (Fig.
11), the laterals were confined within the con-
tainer and became guite deformed after ten years
of restricted growth (Figure 12).

Figure 6. — Lateral Root of a Jeffrey pine showing
constriction resulting from the plastic mesh of
a Conwed container ten years after outplanting.

Table 3. — Mean root and shoot characteristics
of excavated Jeffrey pines ten years after out-
planting in four container types (5 samples per
container type).

Container

Lateral

Tap Root

Green

Weight

Type

Roots1

Diameter

Root

Shoot

(no. )

(cm)

(kg)

9+3-Con\i/ed

19. 6a

2.12

.381

1.39

12-Conwed

19. 6*

2.24

.406

1.60

12-Zeiset

.6b

.99

.227

.73

8-Paperpot

11. 0C

1.26

.112

.42

Means with the same superscript are not signif-
icantly different.

DISCUSSION

The results of this study indicate some interest-
ing, as well as significant, findings regarding
the relationship between container type and field
performance. The highest survival and best growth
occurred on those seedlings outplanted in Conwed
containers while the poorest survival and growth
occurred on the Zeiset and Paperpot containers.
The most significant finding was the lack of
lateral root penetration through the Zeiset con-
tainers. Although the manufacturer's intention
with the plastic coating is to keep the plant
roots divided during the rearing stages in the
greenhouse, the thin coating apparently prevents
lateral roots from penetrating through the side-
walls, even ten years after outplanting. The
manufacturer does recommend punched holes for
guicker lateral root extension on containers
longer than four inches. The results of this
study support the recommendation.

More importantly, and perhaps of significance
in the development and evolution of an accept-
able container, was the relationship between
growth and lateral root development. In this
study, the best growth was obtained on seedlings
outplanted in containers where lateral root devel-
opment was unrestricted. The poorest growth re-
sulted where lateral root development was restrict-
ed. Owston and Stein (1978) reported the poorest
growth after seven years on Douglas-fir and noble-
fir outplanted in one-guart milk cartons. Al-
though their studies were conducted on favorable
sites, the milk cartons remained intact and the
main laterals were almost entirely contained with-
in the carton. They also reported greater height
growth on seedlings outplanted in Conweds than
in either milk cartons or cardboard tubes. Tinus
(1978) has suggested that holes or slits be in-
corporated into the upper sides of solid wall
containers to increase surface laterals for wind
firmness; however, the results of this study in-
dicated that better growth and development re-
sulted where lateral root development was unre-
stricted .

Figure 7. — Root system of a Jeffrey pine with
the 12-Con\i/ed container removed ten years after
outplanting (grid = 4x4cm).

Figure 8. — Root system of a Jeffrey pine with
the 9+3-Conwed container removed ten yers after
outplating (grid = 4x4cm).

The growth and development of seedlings outplanted
in Conwed containers also dispel some of the early
fears of root constriction problems associated
with the plastic mesh type of container. Although
Barnett (1982) reported that loblolly pine roots
can become severly constricted by the plastic
mesh three years after outplanting, the results

Figure 9. — Root system of a Jeffrey pine with the
12-Zeiset container removed ten years after out-
planting (grid = 4x4cm).

Figure 10. — Root system of a Jeffrey pine with
the 8-Paperpot container removed ten years after
outplanting (grid = 4x4cm).

of this study indicated that the lateral roots
can break apart the plastic mesh. The Conwed
material has been manufactured in various degrees
of flexibility, and the material used in Barnett's
study was less flexible than the material used
in this study. Owston and Stein (1978) tested
the same Conwed material as used in this study

12-CARDBOARD

Figure 11. — Jeffrey pine root system showing the
restriction of lateral root development after
ten years in a 12-Zeiset container (grid = 4x4cm)

and reported girdling on the lateral roots. Ihey
found that the lateral roots penetrating the pla-
stic mesh were smaller in diameter than those
penetrating peat-fiber pots. The root constric-
tion problem associated with plastic mesh contain-
ers may reduce growth somewhat; however the problem
appears to be relatively minor and apparently
short-lived compared to the root restriction
problem associated with solid wall containers.

CONCLUSIONS

The acceptance of a container type for any system
will depend on a number of variables. The field
performance of outplanted seedlings will help
evaluate the containers presently available and
will aid the development of future containers.
The higher survival and better overall growth
obtained with the plastic mesh containers suggest
the importance of unrestricted lateral root devel-
opment. The root constrictions which did appear
on the laterals due to the plastic mesh did not
appear to adversely affect the seedling growth
and development compared to the effect of restrict-
ed lateral root development found on the cardboard
containers. Although a biodegradable plastic mesh
container would appear promising, the relatively
high cost of biodegradable plastic has discouraged
further development (Barnett 1982; Barnett and
McGilvroy 1981) .

PUBLICATIONS CITED

Barnett, J. P. Selecting containers for southern
pine seedling production. In: Guldin, R.W.;
Barnett, J. P., ed. Proceedings of the South-
ern Containerized Forest Tree Seedling Confer-
ence; 1981 Aug. 25-27; Savannah, Georgia.
Gen. Tech. Rep. S0-37:15-24; 1982.

Barnett, J. P.; McGilvray, J.M. Container plant-
ing systems for the South. Res. Pap. SO-167.
U.S. Dep. Agric, For. Serv., South. For. Exp.
Stn., New Orleans, LA; 1981. 18p.

Guldin, R.W.; Barnett, J. P., ed. Proceedings

of the Southern Containerized Forest Tree Seed-
ling Conference. 1981 Aug. 25-27; Savannah,
Georgia. Gen. Tech. Rep. SO-37. U.S. Dep.

Agric, For. Serv., South,
Orleans, LA; 1982. 156p.

For Exp. Stn,

New

Figure 12. — Close-up view of a Jeffrey pine root
system showing deformation after ten years in
a 12-Zeiset container (grid = 4x4cm).

Miller, E.L.: Budy, J.D. Field Survival of Con-
tainer-grown Jeffrey pine seedlings outplanted
on adverse sites. In: Tinus, R.W.; Stein,
U.I.; Balmer, W.E., ed. Proceedings North
American Containerized Forest Tree Seedling
Symposium; Great Plains Agric. Counc. Pub.
68:377-383; 1974.

Owston, P.W.; Stein, W.I. Survival, growth, and
root form of containerized and bare-root Doug-
las-firs and noble firs seven years after
planting. In: Van Eerden, E.; Kinghorn, J.M.,
ed. Proceedings of the Root Form of Planted
Trees Symposium; 1978 May 16-19; Victoria,
B.C. B.C. Min. For. /Can. For. Serv. Joint Rep.
8:216-221; 1978.

Scarratt, J.B.; Glerum, C; Plexman, C.A., ed .

Proceedings of the Canadian Containerized Tree
Seedling Symposium. 1981 Sept. 14-16; Tor-
onto, Ontario. COJFRC Symposium Proceedings
O-P-10; 1982. 460p.

Tinus, R.W. Root system configuration is import-
ant to long tree life. In: International
Plant Propagators' Society Combined Proceed-
ings. 28:58-62; 1978.

Tinus, R.U.; Stein, W.I- ; Balmer, W.E., ed. Pro-
ceedings of the North American Containerized
Forest Tree Seedling Symposium. 1974 Aug.
26-29; Denver, Colorado. Great Plains Agric.
Counc. Publ. No. 68; 1974. 458p.

Van Eerden, E.; Kinghorn, J.M., ed. Proceedings
of the Root Form of Planted Trees Symposium.
1978 May 16-19; Victoria, B.C. B.C. Min. For./
Can. For. Serv. Joint Rep. No. 8; 1978.
357p.

Waldron, R.FI., ed. Proceedings of a Workshop

on Container Planting in Canada. 1971 Sept.
28-30; Alberta. Directorate of Program Co-
ordination; Ottawa, Ontario; Info. Rep. DPC-
X-2; 1972. 168p.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the I ntermounta i n
area: proceedings: I n te rmounta i n Nurseryman's
Association 1 98 3 conference; 1 983 August 8-11;
Las Vegas, NV. General Technical Report I NT- 1 68 .
Ogden, UT : U.S. Department of Agriculture,
Forest Service, I ntermounta i n Forest and Range
Experiment Station; 198*1. 96 p.

GROWING CDNTAI NERI Z ED TREE SEEDLINGS
IN A SHADEHOUSF
Thomas M. Smith

ABSTRACT: Initial data indicate containerized
ponderosa Dine (Pinus ponderosa , Rocky Mountain
form) tree seedlings qerminated in a qreenhouse in
early May can be moved to a shadehouse in early
June and successfully grown in Albuquerque, N.M.
Data also indicate that ponderosa pine seedlinqs
sown in early February can be removed from the
greenhouse in early May rather than early June and
may survive a July outplantinq at the same location.

INTRODUCTION

On May 2, 1983, three baskets of seed, each
containing 13 Spencer-LeMaire , Tinus (21.5 cubic
inches ) bookplanters , were sown at the Bureau of
Indian Affairs (BIA) greenhouse in Albuquerque,
N.M. A Zuni, N.M., seed source was used. Two
seeds per cavity were sown. There was a crop of
oonderosa pine (Pinus ponderosa, Rocky Mountain
form) containerized tree seedlinqs present in the
greenhouse that had been sown in earlv February
1983, therefore, qermination conditions were not
optimum. The production greenhouse currentlv
maintains a triple crco schedule producinq
approximately 79,000 containerized tree seedlinqs
per crop. The ourpose of this studv was to
determine the potential for four croos annual lv.
On May 3, 1983, two baskets each containing 52
containerized tree seedlings were removed from
the greenhouse and placed in the shadehouse .
These baskets were nart of the crop that was sown
in early February 1983, and were from a Zuni,
N.M. seed source. It was felt that the weather
was too cold to move the seedlings into the
shadehouse earlier.

DISCUSSION AND RESULTS

The BIA facility in Albuquerque, N.M., is a 30' x
100' double poly nexus style greenhouse with a
shadehouse approximately 100' x 100'. The
fertilizer used is Peters 20-20-20 for the
qreenhouse, Peters 9-45-15 for after-stress and
in the shadehouse, and Peters STEM for trace
element addition in both the qreenhouse and
shadehouse.

In an attempt to determine if crop production
could be increased, two baskets of seed, each
containinq 13 Spencer-Lemaire Tinus (21.5 cubic
inches) bookplanters. were sown on May 2, 1983.
These baskets of seeds were then olaced with a
crop of ponderosa pine containerized tree

Thomas M. Smith is Greenhouse Manager at the
Bureau of Indian Affairs, Albuauerque Area
Office, Branch of Forestry, Albuquerque, N.M.

seedlings that were sown in early February 1983.
All seedlings were from a Zuni, N.M., source.

The germinants were watered twice daily with the
bocm during scheduled waterings and supplemented

with hand waterings

for

two weeks.

No water inq

was done

on the weekends

Table 1

lists the daily

temoerature

extremes in

the qreenhouse from May

2 to June 7 ,

1983.

Table 1 .

— Greenhouse maximum, minimum, ard

current

temoeratures

from 5/2/83 to

6/7/83

Date

Time

Max

Min.

Current

5/2

0733

5/3

0720

5/4

0739

5/5

0727

5/6

0740

5/7

1 1 59

5/8

1200

5/9

0729

5/10

0739

5/11

0735

5/12

0738

5/13

0740

5/14

0800

5/15

0800

5/16

0740

5/17

0^35

5/18

0735

5/19

0730

5/201

0740

5/232

0722

5/24

0735

5/25

0740

5/26

0725

5/27

0730

5/28

0800

5/29

0800

5/30

0814

5/31

0745

6/1

0735

6/2

0740

6/3

0734

6/4

0R00

6/5

0800

6/6

0730

6/7

0715

1 Hygrothermograph clock stopped durinq
evening of 5/20/83 and no recordings available
until 5/23/83.

2 May 23, 1983, the greenhouse crop was
flushed then stressed: germinants were neither
flushed nor stressed.

The temperatures that were maintained in the
greenhouse were within the optimum ranqe for
seedlings in the "exponential" stage, but they
were not optimum for "germination."

During stressing the germinants were watered
Monday, Wednesday, and Friday morning, and were
fertilized within one tablespoon/gallon
20-20-20.

The greenhouse croo and germinants were moved to
the shadehouse on June 7, 1983.

In the shadehouse the germinants received the
following:

A. June 8 - water and fertilize with shadehouse
2 lb. 9-45-15+STEM/6 qt. water.

B. June 10- water from greenhouse lines.

C. June 13 - water and fertilize with shadehouse
2 lb. 9-45-15+STEM/6 qt. water.

D. June 15 - water from qreenhouse lines.

E. June 16 - water and fertilize with shadehouse
2 lb. 9-45-1 5-STEM/6 qt. water.

F. June 17 - water from qreenhouse lines,
fertilize 1 tablespoon/gal. 20-20-20.

G. June 20 - water and fertilize with shadehouse
2 lb. 9-45-15+STEM/6 qt. water.

H. June 22 - water from greenhouse lines,
fertilize 1 tablespoon/gal. 20-20-20.

I. June 27 - water and fertilize from greenhouse
lines, 1/2 lb. 20-20-20+STEM/4 qt. water.

J. June 29 - water and fertilize from greenhouse
lines, 1/2 lb. 20-20-20+STEM/4 qt- water.

K. July 1 - water from qreenhouse lines.

L. July 4 - water and fertilize from greenhouse
lines, 1 lb. 20-20-20+STEM/4 qt. water.

M. July 6 - water and fertilize from qreenhouse
lines 1 lb. 20-20-20+STEM/4 qt. water.

N. July 7 - water and fertilize from shadehouse
lines, 2 lb.9-45-15+STEM/6 qt. water.

O. July 11 - water from qreenhouse lines,
fertilize 3 tsps./qal. 20-20-20.

P. July 13 - water and fertilize from qreen-
house lines, 1/2 lb. 20-20-20+STEM 4 qt/
water.

0. July 15 - water from qreenhouse lines.
R. July 18 - begin water and fertilize from

greenhouse lines, 2 lb. 20-20-20+STEM.
S. Continue watering schedule of 7/18 on

Mondays and Wednesdays, and water only

from greenhouse lines on Fridays

Table 2 records the measurements of the
germinants as of August 1 , 1983.

Table 2. — Measurements of germinants, August 1983

Basket
No,

Max,

Caliper (Inches)
Min. Mean Mode

Median

3/32
3/32
3/32

1/16
1/32
1/16

0.067
0.067
0.066

1/16
1/16
1/16

Basket

Heiqht (Inches)

No.

Max.

Min.

Mean

Mode

Median

4 7/8

1 1/2

3.983

4 7/8

1 3/4

3.635

3 1/2

3 5/8

5 3/8

2 1/2

3.756

3 1/4

3 1/2

Basket

number 1

contained 52

seedlings,

basket

number 2, 51, and basket number 3 contained 50.
The maximum possible number of seedlings was 52
per basket .

Containerized tree seedlings are grown for
spring and summer outplanting. Seedlings sown
in the summer are scheduled for outplanting the
following spring. The goal of the summer
sowing is to produce a seedling that would
successfully overwinter in the shadehouse.
Currently the seedlings are actively growing
and have good secondary needle development.
Chronologically, these seedlings are one month
older than those in the qreenhouse. They are
further developed in all phases of growth than
those that have been in a fully controlled
greenhouse for two months.

On May 3, 1983, two baskets, each containing 52
ponderosa pine containerized tree seedlings
were moved to the shadehouse. ^hese seedlings
were sown in early February 1983 from a Zuni ,
N.M., seed source. The seedlings were not moved
to the shadehouse until low temperatures could
be assured to be above 32° F.

Table 3 details daily Fahrenheit temperature
ranqes in the shadehouse.

Table 3. — Daily maximum, minimum, and current
shadehouse temperatures from 4/29 to 6/7/83

Date

Time

Max.

Min.

Current

4/29

1553

5/2

1615

5/3

1630

5/4

1558

5/5

1615

5/6

1556

5/9

1617

5/10

1610

5/11

1602

5/13

1605

5/16

1613

5/17

1610

5/18

1618

5/19

1630

5/20

1618

5/23

1610

5/24

1610

5/25

1612

5/26

1609

5/27

1612

100

6/1

1610

6/2

1620

6/3

1622

6/6

1604

6/7

1616

Temperatures were recorded from a maximum/
minimum thermometer located on the north end of
the shadehouse. The thermometer was not set up
according to Weather Service specifications. The
50% shade provided by the shadehouse did not
prevent the thermometer from being exposed to
direct sunlight, therefore, the day time highs
are "sun" temperatures. The low temperatures may
be considered representative.

One value of the temperature recordinqs is to
demonstrate the temperature extremes the
seedlings in the shadehouse experienced.
Recordings were stopped on June 7 because a
freeze was no longer considered a possibility and
the purpose of record inq temperatures was to
document any freeze that occurred.

Table 4 records the maximum, minimum , mean, mode,
and median for heiaht and caliper in inches from
two baskets of seedlings from the crop sown in
February 1983 and moved to the shadehouse May 3,
1983. The measurements were taken on August 1,
1983.

Table 4. — Measurements of seedlings removed
from the qreenhouse 5/3/83 as of 8/1/83.

Basket

Caliper (inches)

No.

Max.

Min.

Mean

Mode

Median

3/8

1/16

0.157

1/8

5/32

7/32

3/32

0.144

1/8

Basket

Height (inches)

No.

Max.

Min.

Mean

Mode

Median

2 1/2

4.865

5.25

4.75

6 7/8

4.03

Basket

number

1 contained 52

seedlings and

basket

number

2 contained 50.

The

maximum

possible number of seedlings per basket was
52.

The seedlinqs removed in May are shorter and
have much woodier stems than those removed from
the qreenhouse in June.

The seedlings in the shadehouse were watered
Monday and Thursday mornings and fertilized
with 2 lbs. 9-45-15+STEM/6 qts. water through
the shadehouse lines along with the rest of the
shadehouse seedlinqs. These seedlings were
moved back into the greenhouse on May 23,
1983, for flushing and stressed in the
shadehouse. The Monday and Thursday watering
9-45-15 fertilizer was reinstated after
stressing.

Table 5 records the maximum, minimum, mean, mode,
and median of baskets from the crop sown in early
February 1983, and moved to the shadehouse on
June 7, 1983.

Table 5. — Measurements of seedlings removed
from the qreenhouse 6/7/83 as of 8/1/83

Basket
No.

Max .

Cal iper
Min.

(inches)
Mean

Mode

Median

3/32
5/32

1/16
3/32

0.1 19
0.124

1/8
1/8

Basket
No.

Max.

Heiqht
Min.

( inches )
Mean

Mode

Median

7
7

3
2

4.954
5.02

4 1/2

5 1/4
5

Basket number 1 contained 52 seedlinqs and basket
number 2 contained 52. The maximum possible was
52 seedlings.

CONCLUSIONS

Initial results indicate the potential for four
crops of containerized ponderosa pine tree
seedlings annually at the BIA greenhouse facility
in Albuquerque, N.M. The smaller seedlings
should survive the harsh planting sites in New
Mexico, but only a survival study can determine
this field survival and growth is the bottom line
One month, early May to early June, growth in a
greenhouse with subsequent shadehouse growth
appears to be enough to produce a seedling that
will overwinter in a shadehouse in Albuquerque,
N.M. During an on-site inspection by
Dr. Richard W. Tinus on July 20, 1983, he stated
that these conclusions at that time seemed to be
valid.

The purpose of this paper is to indicate the
possibility of increasing crop production from
three to four crops annually at the BIA green-
house in Albuquerque, N.M. The problems of an
administrative study in a production qreenhouse
are obvious. While all selections made were
random, 2 baskets out of 1,523 may not be a
large enouqh sample, therefore, a statistical
analysis was not performed. The potential may
exist, however, and therefore further research is
needed.

ACKNOWLEDGEMENTS

Special thanks to Dr. Richard W. Tinus for an
on-site inspection to the BIA Greenhouse
facility and providing deeply appreciated
comments.

In: Murphy, Patrick M. , compiler. The challenge of
producing native plants for the Intermountain
area: proceedings: Intermountain Nurseryman's
Association 1983 conference; 1983 August 8-11;
Las Vegas, NV. General Technical Report INT-168.
Ogden, UT: U.S. Department of Agriculture,
Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

ATTENDANCE ROSTER

Ron Adams
New Forests
P.O. Box 561
Davis, CA 95617

Mike Alder and Richard Hildreth
Native Plants, Incorporated
360 Wakara Way
Salt Lake City, UT 84108

Aman Arab

Navajo Tribe Division of Forestry
Box 111

Winslow, AZ 86047

Wes Bates, Nurseryman
Albuquerque Nursery
P.O. Box 231
Peralta, NM 87042

Richard L. Biamonte
W.R. Grace and Company
P.O. Box 517

Travelers Rest, SC 92690
David Borland

Arizona State Land Department
3650 Lake Mary Road
Flagstaff, AZ 86001

Jerry D. Budy
University of Nevada-Reno
1000 Valley Road
Reno, NV 89512

Robert B. Campbell
USD A Forest Service
Intermountain Forest and Range

Experiment Station
860 North 1200 East
Logan, UT 84321

Cynthia Cowen

Bureau of Land Management

P.O. Box 26569

4765 Vegas Drive

Las Vegas, NV 89126

Rodger Danielson
Oregon State University

Seed Labatory
Corvallis, OR 97331

Steve DeRicco

Nevada Division of Forestry
9600 Tule Springs Road
Las Vegas, NV 89131

Gary Dinkel
USDA Forest Service
Bessey Nursery
P.O. Box 38
Halsey, NE 69142

Bill Dunning

USDA Soil Conservation Service
1100 East Sahara Avenue
Las Vegas, NV 89104

Mary Duryea

Oregon State University
Department of Forest Science
Corvallis, OR 97331

Paul J. Edgerton

USDA Forest Service

Pacific Northwest Forest and

Range Experiment Station
1133 North Western Avenue
Wenatchee, WA 98801

Will B. Ellington, President
Lava Nursery, Incorporated
P.O. Box 370
Parkdale, OR 97041

Gregory A. Fancher
Mora Research Center
P.O. Box 359
Mora, NM 87732

Paul Forward
USDA Forest Service
J.W. Toumey Nursery
P.O. Box 468
Ironwood, MI 49938

George Grainger
Alberta Tree Nursery

and Horticulture Center
R.R. #6

Edmonton, Alberta
Canada

Dan Greytak

Nevada Division of Forestry
201 South Fall Street
Carson City, NV 89710

David Grierson

Utah State Forest Nursery

Prison Road

Draper, UT 84020

Bob Gutsch
USDA Forest Service
Eveleth Nursery
Route 1, Box 239
Eveleth, MN 55734

Marcia Hall

418 Birch Street

Boulder City, NV 89005

Dick Hallman

USDA Forest Service

Missoula Equipment Development Center
Ft. Missoula
Missoula, MT 59801

J.R. Hamilton
Production Manager
Box 750

Smoky Lake, Alberta
Canada T0A 3C0

Bob Hammond
P.O. Box 385
Pahrump, NV 89041

Mike Hanson
USDA Forest Service
Intermountain Region
324 25th Street
Ogden, UT 84401

Edward E. Hardin
Oregon State University

Seed Laboratory
Farm Crops Annex
Corvallis, OR 97331

Jerry B. Harmon

Bureau of Land Management

P.O. Box 12000

300 Booth Street

Reno, NV 89520

Gene Hartzell, Nursery Manager
California Headquarters Nursery
5800 Chiles Road
Davis, Ca 95616

Keith Kelly

Nevada Nurseryman's Assoc.

64 LaFayette

Las Vegas, NV 89110

Joanne Kerbauez
Cal Trans
P.O. Box 847
Bishop, CA 93514

H. Khatami an

Department of Horticulture
Kansas State University
Manhattan, KS 66506

Larry A. LaFleur

Pine Ridge Forest Nursery

Box 714

Smoky Lake ,

Alberta Canada T0A 3C0

Roy LaFramboise
N.D. Forest Service
Towner Nursery
Star Route 2, Box 13
Towner, ND 58788

Willis J. Heron
Department of State Lands
Division of Forestry
2705 Spurgeon Road
Missoula, MT 59801

Tom Landis
USDA Forest Service
Rocky Mountain Region
P.O. Box 25127
Lakewood, CO 80225

Richard Hildreth

University of Utah

Salt Lake City, UT 84112

John Hinz

USDA Forest Service
Bessey Nursery
P.O. Box 38
Halsey, NE 69142

Les Holsapple
USDA Forest Service
Lucky Peak Nursery
c/o Idaho City Stage
Boise, ID 83702

Lynn Long

Palouse Seed Company
Box 291

Fairfield, WA 99012

Gary Lyons

5050 Tamarus Street

No. 98

Las Vegas, NV 89109

Patricia L. Malone
3600 Nursery Road
Coeur d'Alene, ID 83814

Carroll McAninch
431 South Kendall
Denver, CO 80225

Bob James

USDA Forest Service
Northern Region
Federal Building
P.O. Box 7669
Missoula, MT 59807

Paul Julien

W.R. Grace and Company
10918 N.W. 27th Court
Vancouver, WA 98665

Robert P. Karrfalt

National Tree Seed Laboratory

Rt. 1, Box 182B

Dry Branch, GA 31020

Doug McCreary
Oregon State University
Department of Forest Science
Corvallis, OR 97331

Bruce McTavish
2396-272 Street
P.O. Box 430
Aldergrove, B.C.
Canada VOX 1A0

Steven Monsen

USDA Forest Service

Intermountain Forest and Range

Experiment Station
753 North 500 East
Provo, UT 84601

Bart Mortensen
5555 Ute Highway
Longmont, CO 80501

Bill Shrope

Palouse Seed Company

Box 291

Fairfield, WA 99012

Pat Murphy

Nevada Division of Forestry
201 South Fall Street
Carson City, NV 89710

Al Myatt

Route 1, Box 44

Washington, OK 7 3093

David Nelson

Pacific NW Tree Seed Spec.
712 W. 25th Street
Vancouver, WA 98660

Brent William Novelsky
Syncrude Canada Ltd.
p'.O. Box 4009
Fort McMurray, Alberta
Canada T9H 2L1

Steven Omi

Oregon State University
Department of Forest Sciences
Corvallis, OR 97331

Thomas Sierzega
Mt. Sopris Tree Nursery
0448 Valley Road
Carbondale, CO 81623

Tomas Smigel

Nevada Department of Agriculture
Division of Plant Industry
2300 McLeod
Las Vegas, NV 89121

Tom Smith

Bureau of Indian Affairs
Forestry Greenhouse
P.O. Box 10146
9169 Coors Road N.W.
Albuquerque, NM 87184

David Sparks

3812 Sunrise Avenue

Las Vegas, NV 89110

LaVell 0. (Pete) Stanger
USDA Forest Service
Pacific Northwest Region
319 S.W. Pine Street
P.O. Box 3623
Portland, OR 97208

George Robison
Nevada Division of Forestry
9600 Tule Springs Road
Las Vegas, NV 89131

Mark Storrs

Greener 'n Ever Tree Farm

and Nursery
8940 Carmel Valley Road
P.O. Box 222-435
Carmel, CA 93922

Frank Rothe
Colo-Hydro, Inc.
5555 Ute Highway
Longmont, CO 80501

Howard Stutz

Brigham Young University

Department of Botany and Range Science

Provo, UT 94602

Anna R. Rubin
P.O. Box 7384
Las Vegas, NV 89125

Richard Thatcher, Nurseryman
USDA Forest Service
Lucky Peak Nursery
c/o Idaho City Stage
Boise, ID 83706

James Sedore, Greenhouse Manager
Washington State Department of

Natural Resources
DNR Greenhouses MQ-11
Olympia, WA 98504

Nancy Shaw

USDA Forest Service

Intermountain Forest and Range

Experiment Station
316 E. Myrtle
Boise, ID 83702

George Shikaze
11771 King Road #206
Richmond, B.C.
Canada V3W 6J3

Dr. Richard W. Tinus

USDA Forest Service

Rocky Mountain Forest and Range

Experiment Station
Forestry Sciences Lab, NAU
Flagstaff, AZ 86001

Mike Verchick

Nevada Department of Agriculture
Division of Plant Industry
2300 McLeod
Las Vegas, NV 89121

Michael P. Vorwerk
Route 1, Box 44
Washington, OK 73093

Don Wermlinger
USDA Forest Service
Lucky Peak Nursery
c/o Idaho City Stage
Boise, ID 83706

Tom Williams

I.T. Energy Systems, Inc.
Box 512

New Plymouth, ID 83655

Robert C. Zobel

Greener 'n Ever Tree Farm

and Nursery
8940 Carmel Valley Road
P.O. Box 222-435
Carmel, CA 93922

■Ct U.S. GOVERNMENT PRINTING OFFICE: 1984—776-032/1074 REGION NO. 8

Murphy, Patrick M. , compiler. The challenge of producing
native plants for the Intermountain area; proceedings:
Intermountain Nurseryman's Association 1983 Conference;
1983 August 8-11; Las Vegas, NV. General Technical
Report INT-168. Ogden, UT: U.S. Department of Agri-
culture, Forest Service, Intermountain Forest and Range
Experiment Station; 1984. 96 p.

Contains 17 papers describing successful procedures,
guidelines, and problems in propagation and production of
native plants. Emphasis is on seed or plant production
for revegetating disturbed lands.

KEYWORDS: native plant production, land reclamation,
planting techniques, shrub adaptation,
nursery practices

PESTICIDE PRECAUTIONARY STATEMENT

This publication reports research involving pesticides. It
does not contain recommendations for their use, nor
does it imply that the uses discussed here have been
registered. All uses of pesticides must be registered by
appropriate State and/or Federal agencies before they
can be recommended.

CAUTION: Pesticides can be injurious to humans,
domestic animals, desirable plants, and fish or other
wildlife— if they are not handled or applied properly.
Use all pesticides selectively and carefully. Follow
recommended practices for the disposal of surplus
pesticides and pesticide containers.

FOLLOW THE LABEL

U.S. DfPAITMCNT Of A6IICUITUIE

The Intermountain Station, headquartered in Ogden, Utah, is one
of eight regional experiment stations charged with providing scien-
tific knowledge to help resource managers meet human needs and
protect forest and range ecosystems.

The Intermountain Station includes the States of Montana,
Idaho, Utah, Nevada, and western Wyoming. About 231 million
acres, or 85 percent, of the land area in the Station territory are
classified as forest and rangeland. These lands include grass-
lands, deserts, shrublands, alpine areas, and well-stocked forests.
They supply fiber for forest industries; minerals for energy and in-
dustrial development; and water for domestic and industrial con-
sumption. They also provide recreation opportunities for millions
of visitors each year.

Field programs and research work units of the Station are main-
tained in:

Boise, Idaho

Bozeman, Montana (in cooperation with Montana State
University)

Logan, Utah (in cooperation with Utah State University)

Missoula, Montana (in cooperation with the University
of Montana)

Moscow, Idaho (in cooperation with the University of
Idaho)

Provo, Utah (in cooperation with Brigham Young Univer-
sity)

Reno, Nevada (in cooperation with the University of
Nevada)

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "The challenge of producing native plants for the intermountain area : proceedings, Intermountain Nurseryman's Association, 1983 conference, August 8-11, 1983, Las Vegas, Nevada"

See other formats