/

Historic, Archive Document

Do not assume content reflects current
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99.551

76D

DEIERMINATION OF ALLOV^ABLE MNUAL TIMBER CUT
ON FORIY-WQ ¥?ESTERN NATIONAL FORESTS

An Analysis of Objectives, Problems, and Methods

with Recommendations

REPORT OF IHE BOARD OF REVIEW
Forest Service

U, S. Department of Agriculture

Kenneth P. Davis, Chairman
Philip A. Briegleb
John Fedkiw
Lewis R. Grosenbaugh

September 3, 1962

Chief's Cominents

The enclosed report was prepared by a Board of Review which was
appointed to examine the timber management planning procedures and
progress of the Forest Service, U. S. D. A. Current stumpage demand
equals or exceeds the total supply available from 42 National
Forests in Region 6 and parts of Regions 1, 4, and 5. Here we
consider it essential to maintain cutting at maximum sustainable
rates. Hence we asked the Board to give special consideration to
this area.

As shown by the tabulations which the Board made, the rate of
cutting on this group of forests has been increased substantially
and consistently as new and more reliable planning information has
become available. Some relatively small additional increases will
be made prior to October 15, 1962. Following this date, cutting
rate increases will depend almost entirely on the increasing ability
of the timber industry profitably to remove and use currently
unregulated material.

The tabulations also show that cutting has been at the planned rate
on this group of forests for some years now. Such tabulations may
obscure local problems. On the other hand, general averages which
include forests with allowable cuts in excess of demand, obscure
the good record of this area where both allowable and actual rates
are significant.

The topics covered in the review are indicated by the titles of the
sixteen recommendations. These cover three general fields: Cutting

rates (Recommendations 1-4, 10 - 12); measurement problems
(Recommendations 5 - 9) ; and administrative problems (Recommendations
13 - 16). The following specific comments are by these groupings.

Cutting rates are influenced profoundly by future utilization goals
and assumptions, the timber economy, the method and level of road
financing, and, to a lesser extent, the size of regulated units.

The first four recommendations are concerned with these factors. As
recommended we intend to continue our policy of relatively large
working circles and to work toward adequate road financing.
Additionally, increasing attention must be given to opportunities
to provide positive margins to low value material through avoidance
of road overdesign and use of stage construction where applicable.

The Division of Forest Economics Research in cooperation with the
Division of Timber Management will consider the feasibility of the
Board's recommendation for expansion of work on economic studies of
the impacts of alternative cutting level schedules.

The recommendation (No. 4) that timber management goals include
definition of tree diameters and grades for final harvest cuts to
be made after the conversion of over-rotation age timber has limited

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M-1299

) CATALOGiHG

2

application. It will clarify the implications of rotation age
decisions for Regions to indicate in their Handbook guide lines
the sizes and timber quality which are expected to be attained
at the felling ages used in calculations of allowable cut.

However, such size and quality estimates will not be used as the
basic assumptions for rotation age determinations. Forest Service
policy has been and will continue to be the use of age at culmina-
tion of mean annual increment as the primary consideration in
determination of the rotation in allowable cut calculations.

Recommendation 10 concerns progress toward more intensive utiliza-
tion. This is the major possibility for further increases in
allowable cutting rates. Significant further progress is dependent
upon both industry and Forest Service action. When problems are
solved so that material which now has marginal and intermittent
value attains a value sufficient to insure stable market demand,
it will be included in allowable cut determinations.

The Western Forest Experiment Stations, working with the adminis-
trative Regions, will give high priority to studies of regeneration
periods on National Forest timber sale areas.

On special landscape management and related areas where modifica-
tions of normal commercial cutting practices must be used the
systems for establishment of average rates of cutting included in
Recommendation 12, will generally be employed. They are being
used for the current allowable cut redetermination for the 42
National Forests. Special situations may make use of other
procedures advisable.

National Forest inventory work was intensified in 1957. The needs
for further intensification, including the need to revise or
supplement Forest Survey procedures to obtain maximum suitability
for management planning purposes are stated in Recommendations 5
and 9. These recommendations are in accord with the orientation,
policies, and programs now in effect for the conduct of timber
inventories .

At the end of 1961 permanent locations for growth and mortality
measurement had been established on 76% of the commercial forest
area of the National Forests. These installations should be
virtually completed within another year or two. This will permit
rapid progress both on growth measurements and on growth prediction
techniques (Recommendation 5, 6). Such inaccuracies as may still
exist in established working circle cuts are most likely attributable
to the growth predictions.

In the Douglas-fir subregion there have been serious problems
associated with methods of product measurement and control. While
less serious elsewhere, inefficient units of measurement have caused

M-1299

3

difficulties in plans and sales. One means to overcome an import-
ant segment of such difficulties is the use of sample tree measure-
ment in timber sales (Recommendation 7) . Western Regions will test
sample tree measurement on a scale adequate to determine its
practicability.

Recommendation 8 is concerned with basic reform in the measurement
of timber in the round. This is a far reaching, long range
consideration. There is no question of the need for such fundamental
reform. The pioneering research in this field now underway is a
first step toward increasing attention to these basic measurement
problems. However, an early change in sale units, as a result of
this work, is not anticipated.

The last four recommendations concern such administrative matters
as the tenure and experience of our personnel and the effectiveness
of our communication with timber users, including our presentation
of cutting rates and accounting for progress under them. While
these items are not concerned with technical problems of allowable
cut determination, it is clearly evident they must be given
adequate attention in order to avoid misunderstandings and
unnecessary controversies.

Changes in the allowable cuts in the 42 Forest area will be
announced in the Secretary of Agriculture's report to the President
by or before October 15.

The thoroughly objective and practical manner in which the Board
of Review examined the problems before it is evident in the report.

I wish to express appreciation to each member for a well done job.

M-1299

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COPY

THE UNIVERSITY OF MICHIGAN
School of Natural Resources

Department of Forestry Ann Arbor

September 4, 1962

Mr. Edward P. Cliff, Chief
U. S. Forest Service
Washington 25, D. C.

Dear Mr. Cliff:

This is to transmit the report of the Board of Review
on determination of the allowable annual timber cut on
forty-two western national forests. Each member of the
Board had, and carried, an indispensable part in the
assignment. The report is truly a joint product.

Sincerely yours, ^

/ s/

Kenneth P. Davis
Chairman

M-1299

Contents

; Page

Introduction 1

(Establishment of Board, assignment, and agencies
consulted)

National forests in the western economy--1962 3

Western national forest management situation 5

Forest inventor ies- -needs , problems and uses 11

General 11

Extensive management plan inventories and growth

samples 12

Intensive area-by-area inventories for allocating

harvests and other treatments 13

Inventories for control purposes--timber sales and

other depletion 14

Inventories for estimation of product out-turn from

trees or logs 15

Units of measurement 15

Prediction of inventory change--especially growth

and mortality 17

Allowable annual cut determination--objectives, problems,

and procedures 19

Nature and objectives of allowable cut determination 19

Timber management rotations 22

Calculation of the allowable annual cut 25

Calculation for forests composed primarily of

even-aged stands 27

Calculation for irregular stands 29

Cut for modified timber use under multiple-use

management 31

Conclusions and recommendations 34

M-1299

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I

DETERMINATION OF ALLOWABLE ANNUAL TIMBER CUT
ON FORTY-TWO I^STERN NATIONAL FORESTS

An Analysis of Objectives, Problems, and Methods with Recommendations

INTRODUCTION

This is the report of the Board of Review established by the Chief
of the Forest Service, U. S. Department of Agriculture, July 6,

1962, in furtherance of a statement made by Chief Edward P, Cliff
to the Senate Commerce Committee on June 18.

The composition of the Board is as follows:

Kenneth P. Davis, Chairman, Professor of Forest Management, and
Chairman of the Department of Forestry, The University of
Michigan

Philip A, Briegleb, Director, Southern Forest Experiment
Station, Forest Service, U. S, Department of Agriculture,

New Orleans, Louisiana

John Fedkiw, Chief of the Branch of Production Economics
Research, Division of Forest Economics and Marketing
Research, Forest Service, U, S. Department of Agriculture,
Washington, D, C,

Lewis R. Grosenbaugh, Pioneering Research in Forest

Mensuration Pacific Southwest Forest Experiment Station,

Forest Service, U. S, Department of Agriculture, Berkeley,
California

The general assignment of the Board is given by the Chief of the
Forest Service: "Broadly expressed, the subject matter for con-

sideration of the Board is policy, procedure, and practical appli-
cation to specific working circles of any consideration which
affects determination of allowable annual cutting rates," It was
also understood that the Board should:

1. "Confine policy consideration to those consonant with

the Multiple Use — Sustained Yield Act of June 12, I960

(P.L, 86-517).

2. Exclude from consideration issues over policy or status

of formally classified areas such as wilderness, wild, etc,

3. Exclude from consideration timber sale programming

problems or timber sale policies."

Working within this framework, the Board had complete cooperation
from the Forest Service in consultation with individuals in the
organization and in access to data. It also had full freedom to
consult with other concerned persons and organizations, and to
develop its report.

M-1299

2

1

r

riie Board reviewed a large mass of written material including a
number of timber management and multiple-use plans. It did not
attempt individual analysis of 115 existing working circle plans
including 39,133^000 acres of commercial forest land on 42
national forests. Rather, the purpose of the Board has been to
concentrate its efforts on major situations, problems, and
principles of general application.

The 42 western national forests, on which primary attention is
centered, were designated as representing those on which timber
demand-supply relationships are critical, making determination of
allowable cuts of particular importance. These forests are in
western Montana, northern and southeastern Idaho, Washington,

Oregon, and California. They are located in Forest Service
Regions 1, 4, 5, and 6. These forests are named and statistics
concerning their present commercial forest area, and past and
present allowable annual cut and actual cut, are given in Summary
Tables 1 and 2 included at the end of this report.

This report was prepared as a result of two weeks of consultation,
analysis, and writing in Portland, Oregon. It was initially in-
tended to circulate a draft of the report for general review by
Forest Service and other concerned people for 60 days. However,
a commitment by the Secretary of Agriculture to report by October 15
on increased allowable cuts on these forests, based on current ad-
justments and recomputation from latest inventory data and some
changes in procedures, made it necessary to complete the report in
much shorter time, vdth very limited opportunity for the Board to
obtain review.

Those consulted by the Board were as follows:

U. S. Forest Service, representatives of the Washington Office
and Regions 1, 4, 5, and 6, and the Pacific Northwest Forest
and Range Experiment Station.

Bureau of Land Management, Mr. Travis Tyrrell and Mr. Rodney
O^Fety, Portland

Bureau of Indian Affairs, I^tr. Earle Wilcox, Area Forester,
Portland

Western Forest Industries Association, Mr, Joseph W. McCracken
and associates

Industrial Forestry Association, Mr. I'Mlliam D. Hagenstein and
representatives of four association members

Western Pine Association, l^tr, Ernest L. Kolbe

Western Lumber Manufacturers^ Association, Inc., Mr. George R.
Craig

M-1299

3

NATIONAL FORESTS IN THE WESTERN ECONOMY--I962

I

The western national forests of Washington, Oregon, California,

Idaho, and Montana now provide more than 30 percent of the timber
supply of the forest industries of these states. Their role in
the economy of these states has changed rapidly and drastically
during the decade of the 1950^ s. At the beginning of the decade
their total timber harvest had just passed 3 billion board feet, a
little more than I5 percent of the industrial timber supply. In
the late 1950’ s the national forest harvest averaged more than 6
billion board feet, somewhat more than 30 percent of the industrial
timber requirements. In the next decade this proportion will in-
crease even further.

The dynamic role of national forests arises from two trends. First
is the growth of the western forest industries in the decade of the
1950’s. Western lumber output expanded from I? billion board feet
in the late 1940’ s to more than 20 billion board feet in the late
1950’s and i960. Plywood output more than quadrupled between 1948
and 1961, increasing from 2,0 billion square feet to 8,4 billion
square feet. Pulp production nearly doubled, increasing from 2,5
million tons in 1950 to 4,6 million tons in I96I. The western
forest industries grew with the national economy during the 1950’ s.
The basis of much of that growth came from fuller development of
the timber harvest potential of national forests.

The second factor in the expansion of national forest timber har-
vests has been the need for evening-out the timber supply of
established industries and stabilizing communities as the private
timber harvest has declined. This was particularly true in Wash-
ington and Oregon where the forest industries were more highly
developed at the end of World War II, In the Douglas-fir subregion,
for example, total log production between 1947 and I96O averaged 10,9
billion board feet with a relatively small average annual deviation
of 7 percent or 756 million board feet. Log production from public
lands in the same period, on the other hand, increased from less
than 25 percent to 38 percent of the total output. Log production
from national forests in western Washington increased from about
300 million board feet to 6OO million feet, and in western Oregon
from approximately 700 million feet to 1,700 million feet.

1/ Pulp expansion came largely from fuller use of the log output ^
through utilization of pl3Awood and sawmill residues and chips rather
than direct increases in log consumption.

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u

The Douglas-fir subregion has not been free from the general economic
pressure for expansion. The pl3nrood industry increased its installed
capacity from 2.2 million square feet to 9»2 million square feet be-
tween 1947 and i960. This came about at the expense of lumber
capacity, for the expansion of the public log harvest was not suf-
ficient both to meet the growth demand of the plywood industry and
to maintain the lumber capacity and output of the subregion. In
1950 the plywood industry utilized only 10 percent of the sub-
region^ s total log production. Currently, its requirements
approach 30 percent of total log production. For its expansion
the plywood industry has had to bid its timber supply awa^'- from
the lumber industry. As a consequence, estimated lumber capacity
in the subregion declined approximately 2 billion feet in the past
decade with nearly as great a decline in lumber output. Expansion
of lumber capacity elsewhere in the western states, however, has
not only offset the decline in the Douglas-fir subregion, but
provided for about 3 billion feet of expansion in output, pri-
marily on species which compete and substitute for those of the
Douglas-fir subregion.

Capacity and output of the western forest industries during the
1950^ s expanded more than the economic demand. Some unused
capacity and overproduction has tended to follow along with soften-
ing of prices and a downward pressure on profits, Limiber prices
through the 1950^ s remained relatively stable and plywood prices
dropped sharply. Their real prices declined relative to competing
materials, improving the competitive strength of wood products,
but not without the downward pressure on profits.

Stumpage prices rose sharply in the early postwar period and main-
tained a high level through the 1950^ s tending to emphasize the
profit squeeze in the late 1950’ s. Another factor which has tended
to complicate the problems of the lumber industry in the most
recent years has been the ability of Canadian producers to expand
significantly their share of the American lumber market.

Under the competitive circumstances and somewhat depressed profits
of recent years, the planned timber harvest from national forests
has come under increasingly critical scrutiny. Earlier demands
for expanding the national forest harvest to its full potential
appear to arise largely from expansion of capacity and maintenance
of a stable flow of logs for established industrial communities.

The more recent pressure seems to arise from a wish to increase
the public log harvest in the hope of depressing stumpage prices
and manufacturing costs to partially overcome the cost advantage
now possessed by Canadian lumber producers.

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5

In the past decade, the log supply from national forest lands has
become a primary factor in the economic life of the western forest
industries. Decisions on national forest timber harvest now in-
volve nearly a third of the industrial log capacity. As private
sources of supply continue to decline in the next several decades
and inter-regional and international competition for American wood
products markets continues to develop, national forest management
decisions on the level and character of its timber harvest will
have increasing economic significance in determining the size,
structure, location and capacity of the western forest industries.

The situation dictates a need for a thorough understanding of the
major economic role that national forest timber management planning
now plays in the economic life of the western economy generally and
western forest industries particularly. The full harvest potential
and its optimum distribution over time should be studied even
though the ultimate decisions must be based on existing policies
and legislation which prescribe attaining maximum yield and better
balance of age classes with a reasonably even flow of products
looking toward an ultimate crop of trees of sawtimber size and
quality (and other crops where soil and site preclude sawtimber
production) ,

WESTERN NATIONAL FOREST MANAGEMENT SITUATION

The total commercial forest area on 42 western national forests
in Washington, Oregon, California, Idaho, and Montana is currently
estimated at 39,133,000 acres. Approximately six percent has been
placed in a modified timber use category and will be subject to
some restrictions due to multiple-use considerations. Indications
are that this percentage will be increased further.

The present inventory is estimated at 639 billion board feet with
approximately eight percent falling within zones classified as re-
quiring modified timber use. The current allowable cut is 7.16
billion board feet, or 1,1 percent of the total inventory and 1.2
percent of the inventory on the unmodified commercial forest area.

The management planning situation on national forests changed
abruptly during World War II and thereafter, as the war effort
and booming economy rapidly accelerated the demand for timber
supply from national forests. In the prewar period the supply of
nattlonal forest timber was of relatively small immediate economic
significance in the western states. Markets were limited, and
during the depression period of the 1930 's sale of national
forest timber was restricted in order to ameliorate the economic
condition of the lumber industry. Accordingly, the allowable cut,
for all practical purposes, was an academic question.

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6

Generally speaking, the national foi'csts were gi-oosly midei’devel—
oped and unable to meet the shift in demand for public timber
after World War II. The general problem centered on inadequacies
in the road systems, inventories, financing, and market forecasts.
The major tasks in the period since World War II have been to
develop more accurate inventories for planning the allowable cut
and bringing it up to the full sustained-yield potential of
national forests, to develop the access road system sufficiently
to harvest the allowable cut, and to obtain the financing
necessary to meet these objectives. The extent to which these
tasks have been achieved are illustrated by Table 1,

M-1299

Table ^1. Relation of Allowable Cut to Actual Harvest, 42 Western
National Forests, Fiscal Years 1952 - 1962.

Fiscal :
Year :

Allowable

Cut : Actual Harvest

Harvest as a Percent of
Allowable Cut

Millions of Board Feet

1952

4,383

2,863

65

1953

4,405

3,652

83

1954

4,714

3,707

79

1955

4,879

4,399

90

1956

5,000

4,707

94

1957

5,225

4,742

91

1958

5,783

4,422

76

1959

6,029

5,924

98

1960

6,163

6,877

112

1961

6,429

5,965

93

1962

6,651

6 , 694

101

Current

7,159

-

-

Includes some timber harvested but not chargeable to the

allowable cut.

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8

The allowable cut estimate has been dncLcused every year and continues
to be increased as inventories are improved, utilization standards
increased, working circles enlarged, and rotations shortened in
accordance with judgments concerning the sustained-yield potential
of the forests. As access roads have been developed, the actual cut
has been gradually raised to the full allowable cut which is the ob-
jective. From 1952 to 1954 the actual harvest averaged 76 percent of
the allowable cut. From 1955 to 1958 it was 87 percent, and since then
it has averaged 100 percent.

During the past eight years the size of working circles for manage-
ment planning and allowable cut calculation purposes has been in-
creased substantially. The number of working circles is now 115 for
the 42 western national forests, and will be reduced to about 70 as
present working circles are further combined in Regions 5 and 6. A
substantial number of working circles now include an entire national
forest. The effect of larger working circles has been to reduce the
sampling error in inventories and to improve the distribution of age
classes in the planning unit. The latter change tends to give a larger
allowable cut. Further expansion of the area grouped under a single
allowable cut control would tend to raise the allowable cut to a
higher level. The effect of such change can be examined and quantified
in studying the harvest and management potential of national forests.
The practical problems of implementing such changes, however, should
be evaluated in conjunction with such examination. It must be recog-
nized that the larger the working circle, the greater the pressure
on and the importance of internal administration in the allocation
and scheduling of the available cut.

Currently, management planning and national forest development are
sufficiently advanced to keep the annual harvest abreast of the
currently determined allowable cut. The principal tasks that lie
ahead with respect to further refinement in determining the allowable
cut are: Further improvements of inventories; better estimates of

long-term sustained-yield potential as may be obtainable from better
growth and yield data; integration of non-timber uses with timber
management; and closer coordination of the species and grade mixtures
on national forests with market developments in scheduling the con-
version of the old-growth timber to well-stocked, managed second-
growth forests.

The 42 western national forests are still primarily old-growth and
over-mature forests with 50 to 70 percent of the stands older than
established rotation age. The management task is one of conversion
to a well-balanced second-growth forest capable of sustaining the
long-term harvest potential, and at the same time, providing an
optimum distribution of the old-growth harvest for the needs of the
western forest industries.

There is timber harvest potential in addition to the allowable cut
available from considerable portions of the gross growth in mature
and overmature timber which is lost annually through mortality and
decadence. An indication of the amount of loss involved is given
in Table 2 which shows approximate mortality rates on public forest

M-1299

9

lands in ,the Douglas-fir subregion of western Washington and western
Oregon. Most of the public old-grox\7th lands tabulated in Table 2 are
on national forests. In addition to these estimated annual losses,
there are substantial accumulations of salvage from past mortality
in the old-growth forests. Other sources of additional timber are
thinnings in younger stands and prelogging and sanitation harvests
in older stands. Some of the timber volume from these partial harvests,
particularly that from salvage, is now added to and therefore charged
against the allov/able cut. The remainder are available through appli-
cation of management practices which increase the total net yield per
acre for any given time period but do not decrease the major harvest
cut and are not chargeable to the allowable cut. These sources should
be made available as forest improvement harvests as rapidly as the
forest industries can economically utilize the harvest material. This
is already being done to a considerable extent in the ponderosa pine
region. Pilot-scale tests are needed in the Douglas-fir region to
develop feasibility of such cutting.

Table 2. Approximate Gross Growth Lost to Mortality, Douglas-fir
Subregion

Age Class

Approximate loss of
gross growth in percent

: Commercial forest area in
; public ovjnership, M acres

40-100

15-30

2,574

101-160

30-60

1,257

161-300

50-90

2,731

301 +

80-100 +

1,311

Total

7,873

Adapted from Fedkiw, J., Advance Roading for Increased Utiliza-
tion in the Douglas-fir Region of Oregon and Washington, pre-
sented at the 51st Western Forestry Conference, Victoria B. C. ,
December 7-9, 1960.

Thinnings accelerate the diameter growth and capture the mortality in
younger stands. They also make available for current harvest that
portion of the growing stock which is unproductive and not needed to
capture the full growth potential of the soil. Prelogging and sanita-
tion cuts in older growth timber harvest the accumulated mortality
and part of the green timber. Partial harvests of this sort in the
Douglas-fir subregion take six to ten thousand board feet per acre.

A quarter to a half is salvage. The balance is live timber, including
high risk trees and small understory trees which are often broken up

M-1299

10

or uneconomic to log in a single-stage clear-cut. Firms using these
partial harvest methods claim about an eight percent increase in the
total yield per acre over the single-stage clear-cuts.

These partial harvest operations are mentioned because they are the
type of management practices which are needed to capture more com-
pletely the full growth and yield potential of national forests, and
to bring the present timber stands closer to optimum growing and
utilization conditions. Such harvests, however, are more sensitive
to market fluctuations at the present than ordinary final clear-cut
harvests. Generally, they are more economical and acceptable to
operators when the timber market is rising or at a high level. Accord-
ingly, the forest should be developed and plans readied to take advan-
tage of the markets as they develop over time. Currently there is a
general market trend toward acceptance of greater volumes of timber
from partial harvest management operations. To take maximum advantage
of future developments, the basic requirements are advance roads and
stand classifications which locate and identify the opportunity for
partial management harvests.

Currently, the national forest road systems are inadequately developed
to permit capturing the maximum grov/th and yield potential upon which
present management plans are based. The basic problem is partly a
matter of a rather inefficient system of road financing and too low a
level of advance road development. Table 3 shows the status of road
development on national forests of Regions 1, 4, 5, and 6. Only about
one-quarter of the total road system has been developed at a time vjhen
the full harvest potential of national forests is being called upon by
the western forest economy.

Table 3. Status of Road Development on National Forests of

a/

Regions 1, 4, 5, and 6.—

Current

:Est. yrs

. : Estimated

: Estimated

annual

; to com-

; cost to

: total mile-

Installed:

rate of

;plete road; complete

Region ; age req.

roads :

construction; system

: road system

miles

miles

miles

years

billions of

dollars

1

108,573

20,611

800

100

$1. 25

4

(Boise N.F.)

11,790

2,215

125

77

.13

(Payette N.F.

) 7,785

1,265

60

109

.07

5b/

58,963

7,132£/

643

75^/

. 75^/

6

76,860

29,469

1,600

30

1.3

a/ Based on

correspondence from

respective

Regions in

August, 1962.

W As of 1953.

c_! Excludes 13,491 miles of unsatisfactory road.

d/ Includes rebuilding of 18,491 miles of unsatisfactory road.

M-1299

11

The present method of financing the development of the road system
has several disadvantages which adversely affect timber yields and
the productivity of the capital represented by the national forest
5,imber resource. Tying road financing to timber sale contracts
essentially precludes any substantial amount of road construction to
open up young stands for thinning. Where there are substantial areas
of medium-aged timber, 80-150 years old, present policy tends to force
premature harvesting of a considerable portion of the area of such
stands in order to open them up for management. On the other hand,
some areas of accessible but less productive and decadent timber stands
have to be left behind in order to extend the road system into un-
developed lands. Where the oldest and most decadent stands are remote
from established access, the present policy defers their harvest until
they can be reached by progressive staggered cuttings through the
intervening timber. Finally, the system sometimes forces forest
managers to allocate allowable cut to stands which are less adapted
with respect to species, grades and location to meeting current needs
of the timber industry, particularly when forest product markets are
unfavorable. Generally the present road financing arrangements force
land managers to use the allowable cut to develop the road system,
whereas roads ought to be financed in a way that will develop the
optimum allocation of the allowable cut and achieve the maximum harvest
potential of national forests.

The most fundamental change needed to attain this potential is a
financing arrangement which makes roads a means or tool for planning
and development rather than an objective of the allowable cut.

FOREST INVENTORIES --NEEDS, PROBLEMS AND USES
General

Information on current inventory of timber stands on the forty-two
western national forests under consideration constitutes the primary
base from which all allowable cut calculations start. Different
objectives or different assumptions as to the future may lead to
radically different allowable cuts, but they should rest on a common
factual inventory base.

There are four main types of inventory sampling vital to intensive or
dynamic management of any forested property.

First is a relatively light but to some degree permanent sample of
current tree sizes, species, and volumes by various tree and area
classifications, such that present structure of the forest is speci-
fied and sampled and that remeasurement of identical trees and areas
in the future will permit efficient assessment of rate and direction
of future changes that can only be guessed initially. Such an in-
ventory involves semi-permanent plots, lines, or sample points that
facilitate associating measurement of each sample tree with its sub-
sequent remeasurement.

M-1299

12

Second is a less complex but more intensive ground-sample of each
individual logging chance to get simple quantitative information on
the location, accessibility, feasibility, and relative priority of
alternative action programs such as salvage cutting, partial cutting
(weeding, thinning, risk, sanitation), and regeneration measures.

Third is a detailed cumulative inventory of sample trees marked for
harvest, trees actually felled, or residues representing trees
harvested, dead, or missing. Intensity of this sampling should be
appropriate to number, value, and variability of trees or logs har-
vested.

Fourth is the inventory relating measurable elements of standing
trees to actual manufactured yield of lumber, plyxvood, poles, chips,
etc. This must be kept up-to-date and representative of both existing
tree populations and existing utilization practices, and is needed for
sales appraisals, estimates of material lost through hidden defect,
and estimates of change in economically recoverable wood volume that
can be made available from inventory.

Each of these inventories is discussed below.

Extensive Management Plan Inventories and Growth Samples

Although management plan inventories of the first type have been
available in primitive form for many years on most of the forty-two
national forests, it is only in the last five or six years that prospects
for more access roads and better markets rendered up-to-date management
plan cruises with relocatable semi-permanent samples a necessity. The
bulk of the forty-two forests now have such inventories although they
have not been completed on a few forests. Periodic revisions of all
plans in the next ten years will require remeasurement of a relatively
small number of semi-permanent sample trees and reproduction areas.

For the most part, such ad hoc management-plan inventories are corre-
lated with Regional Forest Survey techniques, though they tend to be
more intensive and may obtain information in addition to that required
by Forest Survey. Information is so far superior to that previously
available that praise rather than criticism is in order. However, it
should be noted that in coordinating with Forest Survey, compromises
were made on points which weaken the overall value of the information
for management planning purposes. These include arbitrary definitions
of commercial forest land and adequacy of stocking, use of field classi-
fications, types, and averages instead of individual field measurements,
occasional lapses into continuing instead of periodic inventories,
insistence on a 1-acre cluster instead of some more efficient sample
size, failure to employ silviculturally meaningful angle-gauge sizes,
and gearing survey design to photo-volume stratification that cannot
possibly provide most of the needed silvicultural information on
species, tree class, stand structure, growth, and operability.

For the plans resulting from the new and improved inventories, of
course, change information from the new semi-permanent samples is not
yet available. A few forests have been able to remeasure permanent

M-1299

13

plots established in partial cuttings a number of years ago, but
this provides only a coarse measure of periodic growth for a small
and extremely variable portion of the forest and is ill-adapted to
intensive structural analysis. In the years to come, changes in
growth and mortality attributable to more intensive management should
be detectable in the permanent samples long before they can be detected
by successive independent inventories. These semi-permanent samples
should primarily be regarded as measuring survivor growth, ingrowth,
and mortality by various tree classes rather than furnishing accurate
inventories for budgeting sales.

Although the new extensive inventories of the type just discussed are
invaluable for assessing growth and change, the total volumes they
predict as available for harvest will usually be over-estimates and
do not pin-point location of operable areas. There are a number of
reasons for this. The most obvious is that ground samples frequently
fall in small areas where densities may appear operable, but the larger
logging chance in which they lie is inoperable because of low density
of cut, rough terrain, erodability, or the nebulous but real caution
imposed by loosely specified multiple-use restrictions. Photo strati-
fication, of course, is subject to large local errors in volume per
acre and even greater errors where the characteristics of trees
comprising the volume are important.

Intensive Area-by-Area Inventories For Allocating
Harvests and Other Treatments

The second kind of inventory mentioned involves examining individual
operating units on the ground and recording enough data about the land
and timber (tallying sample trees at a few points so as to get a
reasonable estimate of volumes per acre by tree-class) . From this
the unit's operability, relative silvicultural needs, etc., can be
deduced. Where intensive management is feasible now, a truly
diagnostic tally is desirable for every logging unit on the forest
at least every ten years. Something less than that might be adequate
in these forty-two western forests involving large amounts of over-
mature timber. As a minimum, all areas now accessible to roads and
all areas that have undergone at least one cut should be so inventoried,
plus enough additional inventories to provide realistic allocation of
cutting budgets and adjustment of total inventory figures to an
operable base. Estimation of the proportion of overall commercial
forest area and volume that is unavailable because of inoperability
must come from relating these intensive area-by-area examinations to
the much more detailed but less operationally meaningful figures
derived from photo-interpretation with widely scattered ground- samples.
However this matter is handled, it should be done in a clearly
specified, plan-wise manner, not by some hard- to-explain discount
factor whose subjectivity and ex post facto nature breed suspicion.

Not much inventory of this sort appears to be available on most of
the forty-two forests reviewed, with the result that there is no
clear picture of what is both silviculturally desirable and economically
feasible now.

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14

Inventories for Control Purposes
(Timber Sales and Other Depletion)

The third kind of inventory is intended to measure or sample the trees
removed from the stand, and to serve as a basis for paj-ment when the
removal is in the form of a timber sale.

All depletion must be converted to the same basis used in measuring
the standing tree inventory of which it once was a part. This creates
special problems in two situations:

1. Where no measurement of the standing tree can be
secured prior to removal, and where only residues (stump,
top, etc.) are available for measurement, as in the case
of trespass, logging damage, or damage from various types
of construction. Special hypotheses relating missing stem
measurements to residue characteristics must be locally
devised, and resulting estimates are crude at best. As
with the problem of non-respondents in mail surveys,
there is no completely satisfactory solution to this
problem, but it usually does not involve important amounts
of timber.

2. Where major portions of felled trees are scaled in
the form of logs. Special provision must be made for
validly sampling and measuring some marked trees prior to
felling, so that scaled volume can be converted to standing
tree volume, including appropriate allowance for peculiari-
ties of a wide variety of scaling practices, volume tables,
deductions for breakage, and logging residues.

This problem is particularly aggravated in the Douglas-fir region
where various scaling and grading practices are employed by the Forest
Service and outside agencies. Arbitrary assessment or neglect of
taper, measurement of narrow rather than average diameters, and dis-
regard of fractional inches have destroyed any consistent relationship
with standing tree measurements. This chaotic situation will not be
discussed at length, but it is certainly responsible for much mis-
understanding, dissatisfaction, and expensive reconciliation procedures.
Differences as great as plus or minus 25 percent in the numerical
volume assigned to a given felled tree are not uncommon, depending
on what kind of a "board foot" scale was used, how much taper was
neglected, and what was done about non-circularity or fractional
inches. Occurrence of such discrepant inventories tends to under-
mine successful implementation of timber management plans.

A more efficient solution to the second situation (i.e., where an
inventory of timber harvest is needed both as a basis for depletion
and as a basis for sale) is believed to be sample tree measurement.

This is discussed at some length in a later section under "Units of
Measure." Subsamples of percent bark, percent hidden defect, and
percent logging waste can be obtained for appraisal purposes. Whether
or not this method is adopted for sales, the possibility of doing so
with modern techniques (i.e., good sampling designs, optical

M-1299

15

dendrometers, electronic computers, and better units of measure than
ambiguous board feet) should be investigated for the forty- two national
forests involved. The practical experience of the Bureau of Land
Management in the West and the Forest Service Region 8 in the South
should be analyzed carefully, and the participation of research
personnel should be encouraged.

If adopted, there is no doubt that sample tree measurement in the
West will be cheaper than 100 percent log scaling. It will also
provide more accurate measurement of tree depletion by class of tree
involved (poor risk, mortality, overmature, etc.) and will provide
additive measures that can be more accurately related to various end-
product yields under various assumptions as to utilization standards
or efficiency of manufacture. Inventory procedures to secure such
information will be the next item discussed.

Inventories for Estimation of Product Out-turn from Trees or Logs

The fourth type of inventory needed in management involves sampling
the product out-turn (including bark, defect, etc.) from the inventory
taken in the third step discussed above. The usual mill scale study
for appraisal purposes is an example. Although the forty-two forests
under consideration may have obtained an adequate set of inventory
conversion factors, it must be remembered that changes in marked tree
or log scale inventory procedures or measurement units, changes in
utilization practice, and changes in the type of timber marketed
require that the factors be continuously up-dated. Batch yields from
graded groups of logs or trees (instead of more expensive individual
tree or log yields) will frequently be adequate, however.

Units of Measurement

Discussion of the four preceding types of inventory has assumed for
the most part that primary units of measure and variables measured
were universally agreed upon and satisfactory. Actually, this is
far from the true situation. Not only are the units now used
unsatisfactory and controversial, but there is considerable diversity
of opinion as to alternatives which might be better.

Although this is far from an academic problem, an academic approach
might eliminate some misunderstanding and heated controversy. En-
lightened forest management is being seriously hamstrung by clinging
to inefficient units of measure that convey less information than
alternative units or that are so ambiguous that they hardly deserve
to be called "units of measure." The cord and the board foot applied
to round wood suffer from both weaknesses.

In science, a scale should be composed of units of measure that are
unambiguous, consistent, simple in application, and additive--
adjectives corresponding to specificity, reproducibility, simplicity,
and linearity.

A board-foot unit has these attributes when applied to lumber sawed
precisely one inch in thickness, but not when applied to lumber of

M-1299

16

other thicknesses or to logs. How much loss due to trim, slab, edgings,
and kerf does it assume when applied to logs of different size? What
minimum board size and thickness is assumed? What is the assumed gain
in yield attributable to taper in logs of different length and diameter?
What are the effects of non-circularity, visible defects, and invisible
defects?

All of the above ambiguities plus additional ones are present when the
board foot is used as a unit of measurement for trees. What assump-
tions are made as to bark thickness and taper in the upper stem (the
volume table dilemma)? What log length is assumed? What assumption
is made as to cessation of lumber manufacture in the upper stem?

From this, it is easy to see why the board foot is such an ambiguous
unit that nearly a page of text is needed partially to remedy its
lack of specificity. After 200 years, the proliferation of board-foot
definitions has become ludicrous and has imposed a massive conversion
job on anyone who really would like to derive any usable information
from either scaled or cruised volumes in relation to possible product
yields.

Partially as a result, measurements in board feet are not consistent
or reproducible when the same trees or logs are measured by different
individuals, or by the same individuals under different circumstances.
The illogic of letting bucking practices affect inventory volumes by
ignoring more or less taper as logs are cut longer or shorter is
obvious. The illogic of guessing at breakage and unseen defect is not
so apparent, but just as real. These should be estimated by subsampling
and taken into account by the seller and purchaser in their appraisals
and bids, just as grade and lumber recovery are.

Lack of simplicity in application is indicated by the numerous hand-
books, manuals, and texts--each trying to explain differing methodology
and each lending support to the conclusion that board foot scaling is
more of a craft than an objective system for scientifically measuring
something that exists independent of the scaler's imagination.

Finally, to complete the miserable picture, the log or tree board foot
lacks linearity because overrun differs by log or tree size. Hence,
board feet from trees or logs of different sizes cannot be added
together without destroying any consistent relationship between scale
and lumber yield for a given mill operating according to standard
practice.

The cubic foot per se has only a slight advantage over the board foot
in that no ambiguous deduction for kerf, slab, edging, and trim has
been made, so it is not quite so difficult to relate it to yields of
non-sawed products. Unfortunately, the product yields per cubic foot
depend on diameter and assumed taper just as in the case of the board
foot.

A simple solution to the problem of units of measure is available.
Accurate sample tree measurements of tree diameters outside bark at
known heights (using dendrometers and computers) yield estimates of

M-1299

17

cubic volume, circumferential surface, and grade outside bark for
tree sections whose length is also known. Portions of the upper stem
beyond any currently feasible utilization limits may be included if
changing utilization standards are of interest. Bark and defect can
be subsampled by the fourth type of inventory discussed earlier.

Rather than using merely the cubic foot alone as a unit of measure,
it is preferable to use cubic feet, square feet of circumferential
surface, and linear feet. This trio of measurements, accumulated
separately, will allow conversion to lumber yields, fiber yields,
plywood yields, etc., much more consistently and accurately than
either board feet or cubic feet alone. For instance. International
1/4-inch board feet can be easily derived as 9.12 cu. ft. ~ • 71 ^
sq. ft. -1- .04 linear ft. Board feet could not have been derived
from aggregate cubic feet alone without knowing what sizes of trees
comprised the aggregate volume, nor could aggregate cubic feet have
been accurately derived from board feet alone.

Felled timber can similarly have measured diameters and lengths
automatically converted to cubic feet, square feet of surface, and
linear feet. Units of measurement should ordinarily include bark
because that is what is directly measurable in standing timber (note
standard acceptance of outside bark basal area and d.b.h. measure-
ment). Bark, defect, and product yield obtained from subsampling
should_ be taken into account in product yield conversions such as are
needed in appraisals and bidding, but should not be allowed to con-
taminate basic tree measurements. This does not mean that inventories
cannot be converted to as many different types of units as are
desirable. Total weight, moisture percent, dry-wood specific gravity,
etc., may be desirable in estimating certain product yields, but they
can always be related to volume, surface, and length. In certain
situations, such as yard or jackladder inventory, it may be more
efficient to measure weight and linear feet of all or part of the
felled trees, but these can be related to standing tree volume,
surface, and length based on a much smaller sample.

All in all, it seems that adoption of more informative, less ambiguous
primary measuranent units such as cubic feet, square feet, and linear
feet in place of board feet will be desirable in the near future or
else management planning and sales will bog down in a morass of
unnecessary mensurational difficulties. The fact that lumber standards
already deviate so far from the nominal one-inch standard lumber thick-
ness (and may soon deviate more) indicates a real need to divorce
manufacturing practice from primary units of measurement used in
inventory.

Prediction of Inventory Change (Especially Growth and Mortality)

Inventory change is the algebraic sum of survivor growth, ingrowth from
trees below inventory limits, mortality, planned harvest, damage from
various sources, and trespass. Ordinarily, depletion items such as
planned harvest and logging damage are best measured by special
inventories for control purposes discussed earlier, while growth
of all sorts and normal mortality are measured on semi-permanent

M-1299

18

samples also discussed earlier. Until this latter infonnatiuu is
available, growth must be estimated from yield tables, and its
accuracy or applicability cannot now be assessed. Remeasurement
of the semi-permanent samples unfortunately is still 5 to 10 years
away.

Certainly the number and quality of normal yield tables available in
the 42 western national forests exceeds that of most other areas in
the United States. The major question is how to handle stands which
are not normal (some partially cut) now found on the bulk of the
forested acreage, and how to handle the variety of situations which
will probably be deliberately achieved under intensive management.
Although adjusted normal yield tables or other empirical yield tables
may serve for first estimates of growth, their assumptions become
intolerable after one or more growth periods have elapsed and permanent
sample remeasurements are available. But unless systematic plans are
made soon to incorporate growth information from permanent samples
into growth predictions and allowable cut calculations, the samples
will not contribute as much to maRagement planning as they should and
an opportunity to demonstrate both professional skill and freedom
from subjective bias will be lost.

There are four major approaches to using permanent samples to adjust
allowable cut at the end of a planning period.

First, remeasurement of the samples may merely furnish a new inventory
base for the start of the next regulatory period. Other things being
equal, allowable cut v;ill then tend to rise if inventory exceeds that
which would have existed had initial assumptions as to growth been
exactly borne out, or fall if inventory is less than expectation.

Use of permanent samples in this manner does not justify their high
cost, since two successive independent inventories would have been
cheaper and more satisfactory.

Second, age-class growth experience graphs can be built up for
subsequent use with the familiar tabular area-volume check of periodic
growth with periodic cut. Such experience graphs will replace the
normal or empirical yield tables and can better take into account

actual site, actual density, and prior history. However, a long time

must elapse until enough data are available to extend them the entire
length of the rotation, and they must be subjectively fitted with
almost as much strong-arming as in the case of empirical yield tables.

Third, net or gross growth percents, for initially different tree
classes in the permanent samples may be used for short-term projections
of the terminal tree classes. Although this method is often thought of
as being especially adapted to uneven-aged management, it is equally
useful in even-aged management. It has less appeal where the bulk of

the stand is static old growth, but can be used even there if partial

cuts are intelligently allocated to second-growth stands. The main
problem is to ensure that the volume of allowable cut is taken from
old-growth stands most in need of being harvested and regenerated, and
from components of second-growth stands when such removal will either
reduce loss from mortality or stimulate growth of residual stems.

M-1299

19

Fourth, nonlinear functions employing measurable elements of stand
structure to calculate stand development (but with arbitrary param-
eters) ■ may be used to predict growth of permanent samples. Actual
deviation from predictions will feed back to generate more realistic
estimates of parameters which are then used to predict growth for the
subsequent period. The effects of expected weather difference may be
analyzed if desired. This is probably the most efficient use of
permanent growth samples. Since yield tables have no explicit pro-
visions for predicting change due to heterogeneity in density, age,
or size, they cannot be used in this way. Ordinary multiple linear
regression analysis is a crude form of the structural approach, as
are techniques concerned only with projection of diameter distributions.
It is to be hoped that research underway in several places will lead to
better methodology than is now available.

One or more of the four methods outlined above should be selected
before remeasurement of the semi-permanent samples. In the likely
event that any but the first is chosen, the method of prediction used
in the current management plan should be applied to each semi-permanent
sample to permit later assessment of whether assumptions underlying
the method were overly optimistic or overly conservative.

ALLOWABLE ANNUAL CUT DETERMINATION- -OBJECTIVES,

PROBLEMS, AND PROCEDURES

Nature and Objectives of Allowable Cut Determination

The renewable resources of the national forests are traditionally
managed under a policy of sustained yield. Regulation S-3 requires
that timber resources be managed for the greatest lasting benefit to
the country and to the end that the permanence of yield and useful-
ness of these resources will be assured. S-3 recognizes that orderly
harvesting of timber by methods, at rates and at the proper time to
provide a continuous yield is an essential management objective.

In addition, the Multiple Use-Sustained Yield Act of June 12, 1960,
has since required, by Congressional and Presidential direction, the
maintenance of national forest productivity to insure perpetual
optimum-level annual or regular periodic output of the various
renewable resources. Forest Service policy, as given in the Timber
Management Manual, recognizes that optimum levels of forest product
yields will vary with markets, total use needs, and current working
circle conditions. The Manual states that generally the output
should increase as wild forests approach an organized condition and
the intensity of management is increased. Management must be such
that large, sharp, or long sustained decreases in yield do not occur
except as the possible result of unforeseen catastrophes. Minor
temporary yield depressions may be permitted if insuperable losses
are prevented thereby.

M-1299

20

Timber cutting policy for the national forests is further described
by Chief Cliff in his May 7, 1962, memorandum to Secretary Freeman,
Proposal Number 1:

"The Forest Service shall develop an orderly program
of timber sales designed to obtain regular harvest from
commercial forest areas of the National Forests on a full
sustained-yield basis in accordance with policies estab-
lished for multiple-use management and protection of
National Forest resources. Attainment of this objective
in annual timber sale programs must necessarily depend
on the finances available, local market demand for
stumpage and adequacy of transportation facilities."

It is Forest Service policy to manage each working circle for the
production of crops of sawtimber size and quality from all suitable
forest types and sites, unless exceptions are approved for a
particular working circle or part thereof. It is policy also to
produce other products (such as pulpwood, posts and poles), (1) from
intermediate cuts wherever practical in conjunction with sawtimber
production, (2) from trees and parts of trees below saw log size or
quality on areas of regeneration cutting, (3) from forest types and
sites on which it is not practicable to produce continuous crops of
sawtimber size or quality.

In the broad sense, allowable cut under sustained yield management is
the average volume that may be harvested annually during a planned
period of operation from a given forest unit, xizhich will result in
a sustained yield of timber products and the eventual attainment and
perpetuation of an approximately balanced distribution of tree age or
size classes and desirable stocking. Sustained yield capacity is the
highest uniform yield that may be sustained on a given forest unit
under a specified intensity of management and with a balanced distri-
bution of timber age or size classes. Management for sustained yield
implies continuous production with the aim of achieving, as soon as
practical, a balance between net timber growth and harvest by annual
or somewhat longer periods. Allowable cut is synonymous with sustained
yield capacity when the balance of timber age or size classes and the
balance between growth and harvest are achieved.

On the western national forests, characterized by wide variations in
timber merchantability, accessibility, markets and operating con-
ditions, the term "allowable cut" is used in a specialized sense.

Here the allowable cut is the timber volume, for which there is
assumed to be a reasonably active and steady market, that may be
harvested annually during a planned period of operation, and which
will result in a reasonably uniform sustained yield of timber products
and the eventual attainment and perpetuation of a balanced distribu-
tion of tree ages or sizes and desirable stocking.

Most western working circles contain timber of marginal merchantability
or accessibility under current operating conditions that is not
included in the designated allowable cut. Working plans show the
volume of this material that is available for harvest as an addition

M-1299

21

to that included in the allowable cut. This material is variously
referred to as "supplementary available cut," "additional cutting
objectives," or "unbudgeted cut." Included in this category, for
example, is the estimated annual volume of tree mortality in Douglas-
fir region forests, potential thinnings, volumes in alder and other
hardwoods, volumes in marginal lodgepole pine stands and of timber
on very steep or unstable soils not loggable by current methods without
causing intolerable erosion.

Theoretically, such timber will be available for cutting if and when
active markets and acceptable operating methods are developed for it.
Minor amounts of this timber have been harvested in the past, but
its contribution to the economy is sporadic and undependable. It
would be unrealistic and confusing to include such volume in the
formally designated and regulated allowable cut. The national
forests are trying to develop active markets for this marginal
material, and as reasonably steady demands for it may be realized,
this additional volume will then be logically included in the
allowable cut.

The Board believes that the Forest Service should continue and
strengthen its efforts to develop uses and operating methods that
will increase the value of this marginal timber as an economic
industrial raw material. This represents an opportunity to increase
the allowable cut, and to reduce the misunderstandings about allowable
cut figures and the supplementary cuts possible when conditions permit
on the national forests.

The technical objectives of sustained yield timber management are:

1. To obtain the maximum yield of timber products possible.

2. To provide for an essentially uniform yield of timber

products.

3. To attain or perpetuate a balanced distribution of tree

age or size classes and desirable stocking capable of

producing the forest's full potential timber growth.

These three objectives are simultaneously attainable only in a so-
called fully-regulated forest with a balanced growing stock; they
are not all immediately attainable in such wild forests in the
beginning stages of management as characterize the western national
forests.

For example, the maximum yield of timber from a predominantly mature
or overmature forest would be obtained by immediate harvest and
regeneration. Such a procedure would not realize the benefits of
uniform yield, stabilized industry, markets, and community support
which are the goals of the second objective. Nor would such an
accelerated harvest attain a balanced distribution of forest growing
stock needed to provide for a uniform yield of timber at capacity
in the future.

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22

Likewise, cutting to provide a uniform yield of timber from a mostly
mature or older forest cannot realize the maximum total yield possible.
Such cutting would achieve the second objective and accelerate progress
toward the third, but at some sacrifice in total timber yields.

The relative priority assigned to each of the three above objectives
of sustained yield management must be a managerial decision. In
management of the western national forests emphasis is placed upon
achieving a reasonably uniform yield of timber. This fosters
stabilization of industry, dependent communities and timber supply,
and, in addition, stimulates progress toward a fully-regulated forest
which can produce uniform yields at full capacity in the future.

In working circles having a very high preponderance of old-growth
timber moderate adjustments may be made in the uniformity of timber
yields and progress toward balanced growing stock if the total yield
of needed timber products can be significantly increased thereby.

Thus, allowable cut for a given forest varies with objective of
management as well as with such measures of timber volumes, growth,
degree of utilization and effectiveness of forest management as are
available. And it follows that changes in objectives or in measured
timber volumes and growth or in the degree of utilization will result
in changes in the allowable cut under sustained yield management.

Timber Management Rotations

In the management of forests composed of even-aged stands for timber
production, determination of the average length of time required to
grow the major harvest of timber products to a desired size and
average level of maturity is a critical consideration. This,
together with the regeneration period necessary to establish a new
stand, is the regulatory rotation which defines the average length
of the "turnover" period, the time between major timber harvests.

The rotation also defines the average rate of cutting by area over
a working circle unit. For example, a rotation of 100 years implies
that the total forest area will be cut over in 100 years. This makes
decision as to the average rotation particularly important in the
management of forests including large areas and volumes of old-growth
timber as do the 42 western national forests. This is where interest
in the rotation currently centers. The shorter the rotation, the
faster old-growth stands will be cutover and the greater the consequent
current cut, although this cut is not directly proportional to a change
in rotation length because the impact on the growth of all stands in a
working circle must also be taken into account.

There is no single or infallible method of determining the average
rotation for a working circle; fundamentally, it is an integrative
managerial decision with a number of considerations to be taken into
account and balanced.

Common practice on the western national forests is to set the cutting
age rotation at the culmination of mean annual increment (volume
attained at a given age divided by the age) measured in terms of the

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23

merchantability units primarily harvested, board feet in this situation.
This is the age at which the board foot production of a natural stand
maximizes. The length of the period so indicated naturally varies by
species and quality of the land for timber growing--the site.

The basis for cutting age rotation determination on the national forests
is primarily a body of forest information given in what are known as
normal yield tables that have been prepared for principal western forest
types. These tables show volumes of natural, uncut and fully-stocked
stands that are attained on given sites and for given ages. This body
of data is the best single source available, but its use is tempered
by consideration of empirical yield information, where available,
gained from stands under management.

The length of the regeneration period elapsing between the final harvest
of a stand and establishment of adequate forest reproduction of desirable
species for the next crop must be added to the cutting age rotation.

It cannot be assumed that new reproduction immediately replaces the
stand harvested; there is some time lost under the best of conditions.
This regeneration period is a part of the regulatory rotation. For
example, if the cutting age rotation is 90 years and the regeneration
period is 10 years, the forest must be organized on a 100-year
regulatory rotation to provide that the desired cutting age of 90
years is achieved.

The length of this regeneration period can only be determined by the
facts of experience on the ground. At present, the Forest Service
uses between 5 and 10 years and believes that 10 years is optimistic
in some situations. As better regenerative methods are employed, the
period will be shortened accordingly. Systematic and objective
methods of periodic evaluation are necessary and more effort is needed
in this direction. The length of the regeneration period is a matter
of cold fact on the ground, not of opinion and is variable area by
area. It cannot be ignored nor should it be a basis for general
built-in optimism or conservatism.

Use of the above basis for determining the length of the regulatory
rotation indicates western rotations ranging from 80 to 160 years.

It does not seem helpful here to detail past rotation history on
these 42 forests. The specific length depends on the forest type,
average site, and the utilization assumptions made plus the
regeneration period. For example, a cutting age rotation based on
Scribner Decimal C log rule and utilization of trees 11 inches in
diameter breast high and larger is longer than a rotation based on
International 1/4-inch rule including all trees 7 d.b.h. inches and
larger. The latter assumes more complete utilization which accounts
for most of the difference. The rotation would be still shorter
were it based on cubic foot utilization down to 4 inches.

During the past decade tremendous changes have occurred in the
development of timber management on the western national forests, in
the importance of this resource to the economy, and in the more com-
plete utilization of timber harvest as previously discussed. Rota-
tions have been substantially shortened accordingly. A change in

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policy adopted in 1961 basing the cutting age rotation on culmination
of grox'/th in terms of International 1/4-inch rule including trees 7
inches and larger to a 6- inch top is noteworthy. This shortens
existing average rotations, commonly based on Scribner rule (and
excluding trees smaller than 11 inches d.b.h.), generally from 10 to
25 years. This change envisages economic utilization of smaller
trees in the future. It accounts for much of the increases in
allowable cuts now being calculated on the basis of latest inventory
information available.

An important consideration in rotation determination stems from the
nature of yield tables currently used as the primary basis for cutting
age rotation calculation. They envisage fully-stocked natural stands
that are cut only once--at rotation age. They do not measure the
total growth made in a stand during its life, much of which might be
captured by intermediate cuttings to forestall and recover mortality
that naturally occurs, and to improve the quality growth of the stand.
To the extent such intermediate cuts can be made and financial con-
siderations of costs and returns are injected, rotation length is
changed. It may be either longer or shorter than that determined
by culmination of mean annual increment of the main stand only,
depending on the particular cutting and value assumptions employed.

The degree to which intermediate harvests can profitably be employed
in the future and whether, if so, the western forest industry may come
to be primarily on a fiber rather than a saw log basis, are matters of
long-range projection and an arena into which the Board does not enter.
It is aware of the present utilization situation and of trends, par-
ticularly as indicated on the more intensively managed private
properties .

Under fairly intensive management of well stocked and growing stands,
rotation length may not be a particularly critical consideration.

As long as trees and stands are well within their range of physio-
logical good vigor they can maintain high net volume and value
growth rates per acre with comparatively low stand densities over
rather long periods of time. Decision as to time of major harvest
depends on how long what is considered a satisfactory rate of return
can be maintained in view of current utilization. The situation is
analogous to a factory. As long as it is efficiently productive, no
one would tear it down just because it had been used some arbitrary
number of years. The same is true in a forest stand. There is no
point in liquidating it and undergoing the very considerable expense,
loss in time, and some very real hazards and uncertainty in rebuilding
it through regeneration, as long as it is producing efficiently.

It should also be recognized that average rotations as now applied
are flexible as in practice local site quality, stand, and regenera-
tion conditions are taken into account. The working circle rotation
is a guiding average that is necessary for regulatory planning but
not an inflexible rule in application.

A direct method of rotation determination is to decide what size and
character of products are primarily desired. If, for example, they

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25

are trees averaging about 18 inches in diameter, the rotation is the
time necessary to grow them. This time is a compound of species,
site, and most important, the management methods employed. By proper
spacing, and application of partial cuttings to maintain growth rate
of major crop trees, it is possible to produce them in much shorter
time than indicated by American normal yield tables which are con-
servative in this respect as they are based on unmanaged natural
stands. The length of a rotation based on desirable product size
is consequently variable, being a function of timber management
methods employed. This is an area in which growth and stand structure
studies are needed.

As indicated, there is no single or infallible method of determining
a rotation. In dealing with the realities of the present situation,
an average rotation length, including a necessary regeneration period,
has to be set to give a planning framework for orderly management
providing for sustained production. As previously stated, its
immediate significance in the case of most of the 42 western forests
is as a means of controlling the rate of cutting in old-growth stands;
the harvest impact from managed stands is still largely in the future.
The method presently employed by the Forest Service (culmination of
mean annual increment based on International 1/4-inch rule in trees
7 inches d.b.h. and larger to a 6-inch top) is defensible and seems
a reasonable median between very short and unreasonably long rotations.
As better data on growth under management accumulate and utilization
trends further develop average regulatory rotations should be changed
accordingly. They may be shorter or perhaps longer in some situa-
tions. Regardless of what the future may bring, the Board feels
rotations must be and are set on reasonably foreseeable realities.
Continued analysis and appraisal is necessary.

Calculation of the Allowable Annual Cut

All the facets of timber management come to focus on determination of
the amount and kind of timber that can be harvested from a forest
property during a particular period of time. The definition, com-
ponents, and objectives of allowable cut determination, and its
importance on the 42 western national forests to the western economy
have been discussed. The purpose here is to examine basic methodology
employed.

At the outset, it is essential to recognize that an allowable cut on
the national forests--and elsewhere--is determined for a particular
property for a set period of time, and is based on inventory and
other forest information available at the beginning of the period
plus forecasts of the future. In this sense, all allowable cuts are
provisional. They can and should change as does the situation and
information available.

For these reasons allowable cuts cannot be backdated to apply before
their planned harvest period or safely projected beyond it. Regarding
backdating, suppose it were true that a given forest unit had sub-
stantially the same timber volume 40 years ago as now and could have
yielded about the same cut as estimated now. It cannot be supported

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26

that this 40 years of possible cutting li3<3 a<^cnTmil sted, could be
harvested in a lump now, and still proceed with the same annual cut
under sustained yield principles. Similarly, projection ahead -of
the planned period is uncertain as conditions change. There can be
major fires, insect epidemics, and shifts in utilization. The basic
point is that all these factors are periodically reassessed at the
beginning of each plan period, normally 10 years on the national
forests, and an allowable cut determined accordingly. Interim
adjustments are also made as changed conditions and information
warrant.

The basic foundation for determination of the allowable annual cut
is forest inventory data (including predictions of growth and yield),
applicable knowledge on how to regenerate and grow stands, and
prognostications regarding accessibility, and utilization. This
body of information is applied to a specific area of forest land
available for commercial forest production including areas in which
timber use is modified to meet multiple-use objectives.

A considerable act of faith is embodied in allowable cut determination
on the national forests. In timber management planning, it is
assumed that needed additional roads will be built, that stands will
be satisfactorily regenerated within the regeneration period allowed,
that adequate protection will be given and productive silviculture
applied, that utilization envisaged can be commercially achieved,
that timber volumes estimated as available for cutting from complete
sampling inventory data can, in fact, be made a reality in terms of
operable timber sales, and finally, that sales can be financed and
programed to meet the Forest Service objective of making the
allowable cut actually available. These things cost money and
require continued financial support to achieve.

Over the years, a considerable body of techniques has been developed
for calculating an allowable cut which are expressed in various
formulas and procedures employing area, volume, and combined
approaches. Basically, area and volume approaches are not separate
but complementary, as volumes are cut on areas and both must be con-
sidered in scheduling a cut on the ground. The Board is aware of
these various approaches but will not review them here. Rather, the
aim is to cut through them to consideration of basic principles and
procedures applied on the 42 western national forests.

There are two general kinds of forests to consider and regulatory
approaches differ accordingly. First, are forests that are
primarily composed of even-aged stands and second, those that
are composed of irregular stands of a generally mixed-age character.

It should be made clear that, with the latter, it is not necessarily
assumed that uneven-aged management will be permanently continued,
but only that such stands cannot be classified by age because of
their present structure and, at least currently, are handled on an
uneven-aged regulatory basis. Each group will be reviewed
separately.

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Calculation for Forests Composed Primarily of Even-aged Stands

These forests are characteristically Douglas-fir, Sitka spruce-hemlock
western white pine, and the mixed conifer species associations. They
are commonly called the west side forests in Washington, Oregon, and
California, but forests of the same general character also occur in
parts of Montana and Idaho. Nearly all of the working circles in
this group (there are a few exceptions, notably the Siuslaw) character
istically include large areas and volumes of old-growth timber.

Various formulas and procedures are used. The most common is termed
the Hanzlik approach which consists of two parts, a formula to give
an indicated or trial cut, and an accompanying area-volume check
which is the real control. The formula is:

Allowable annual cut = Annual growth 4- Volume of mature timber

Rotation

It was designed for West Coast areas including substantial areas
supporting old-growth stands. It is not suitable for use in forests
of predominantly young stands in which growth and availability of
harvest-size material is the primary consideration, or for entirely
old-growth forests for which the formula reduces to essentially
straight area control.

In application of the formula, the volume of mature timber is
usually considered as being that shoim in the inventory as older than
the rotation adopted. Annual growth is estimated in a number of ways;
from periodic annual increment as determined by the inventory, from
adjusted normal yield tables, or from empirical yields tables derived
from the inventory. In any event, the indicated cut is regarded as a
trial figure only. It can be, and is, determined from the Austrian
or other formulas, or from just an educated guess. Use of a formula
is not a critical matter.

The final allowable annual cut is determined by what is termed the
area-volume check or the tabular method. In making this check, growth
of the various component stands in the forest unit is estimated and
specific techniques vary. Adjusted normal yield tables are often
used. The adjustment may be a flat percentage of yields indicated
by normal yield tables, or yield tables adjusted for stocking and
approach toward normality by the Girard-Briegleb growth factors.

A more direct approach is to derive an empirical yield table
directly from the inventory data pertinent to the particular working
circle under consideration. Essentially, this means that an average
trend line is determined, usually mathematically, from the age-volume
relationship given by the inventory data. From this established
trend, the growth of any stand, say 30 years old at present, to
rotation age, for example 90 years, is estimated on the basis of
what stands in the working circle of similar site and stocking
actually have produced. The process is conservative in that possible
increased yields in the future from stands under management are not
estimated. The estimate is based on present realities.

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The essential feature of the check method is to determine an even
annual volume of cut that can be sustained for the rotation period.
Basically, it is the solution of a problem containing several con-
ditions and variables. These are:

1. That the total commercial forest area is to be cut
over during an established rotation planning period.

2. That stands are to be cut in approximately the order
of their age starting with the overmature timber, or, in
the case of irregular stands, in the order of whatever con-
dition classes may be established starting with those having
highest priority for cutting.

3. That an approximately even flow of annual harvest
volume is to be maintained.

4. That there is a certain existing distribution of age
classes by area (which may also be classified by site
and stocking) or forest condition classes, and that these
stands will grow at certain estimated rates (not necessarily
constant or linear).

5. That timber of less than rotation age, or of some
specified age less than rotation age and for some
specified time duration, will not be cut during the
rotation period. This fifth condition may or may not
be formally imposed; in practice, it usually works out
that little timber under rotation age is cut anyway.

Given these conditions, there is some volume of annual cut that will
satisfy them.!./ This volume is determined by a cut-and-try process
starting x^/ith a trial annual cut figure and repeating the process
until one is found that can be sustained over the rotation period
and forest area. This means that a constant annual cut is projected
through the area of age or condition classes in order of cutting
priority. The time required to cut each as they are reached is
determined and also their volume at the time of cutting. The sum
of these cutting periods necessarily equals the rotation. The cut
is normally adjusted so that the sum of cutting periods comes out
to not more than plus or minus two years of the established rotation.

This is volume regulation and it should be recognized that a weakness
of any volume approach is that the annual cut figure so determined is
entirely controlled by volume inventory and growth estimates. If
these estimates are in error (and their basis in the present stage of
management information is rather crude) , or if volume estimates cannot
be translated into timber cut in operable sales, there is no assurance
that the working circle area will, in fact, be covered and planned
timber management measures will be applied to the forest area.

1^/ Theoretically, there could be more than one solution,
especially if the yield table projection curves are not ascending
but dip down xi/ith older age classes. In practice, the possibility
of multiple solutions is not important.

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The approach does not include any specific objective to improve future
age class distribution; variable areas are necessarily cut over and
regenerated during the rotation period to maintain an even flow of
harvest from an unregulated forest. Improvement in age class-area
distribution does occur as a by-product of the check procedure and
results from the fact that the working circle is planned to be cut
over systematically. In practice, the improvement is probably ade-
quate, all things considered, and it must be recognized that the
management situation is reassessed at about 10-year intervals. The
Board believes, however, that some direct attention to achievement
of future age class regularity through modified area control could
be injected into the allowable cut determination process without
undue violation of the need for reasonably even harvest flow.

The basic point is that there is no painless way to make progress
toward regulating an unregulated forest. Reasonable progress toward
better age class distribution, certainly one important aim in timber
management for sustained yield as previously pointed out, is in
partial conflict with attainment of an entirely even flow of harvest.
Some reasonable compromise is needed.

The area-volume check approach should be recognized as a variation of
the ancient and time-honored area and volume allotment procedure
applied to western forest conditions. It is a flexible approach.
Limiting conditions established can be varied to suit the circum-
stances and the procedure provides a framework for the working out
of an allowable cut in line with realities and needs--which is the
essence of good forest management on the ground.

In summary, the Board believes that the methods now being applied to
determine allowable annual cuts in forests composed of even-aged
stands give reasonable and defensible results. It does not feel
that any single approach should be prescribed; forests and conditions
are too variable. Continued scrutiny of methodology is important to
insure that the best available procedure and data are employed. The
real questions about allowable cuts do not lie in improved mathemati-
cal procedures as such, but in the need for (1) better knowledge of
the forest and its growth, (2) policy regarding the speed of transi-
tion from dominantly old-growth to younger, managed forests, and
(3) present or projected utilization upon all of which methodology
is based.

Calculation for Irregular Stands

Allowable cut for the extensive ponderosa pine, mixed conifer and other
irregular forests on the western national forests is calculated by a
variety of formulas supplemented by area-volume allotment checks as
previously described. The Austrian formula is most frequently used
for computation of a preliminary estimate of cut:

Allowable

annual

cut

Average

annual

= growth in + Measured volume - Desirable volume
conversion Years in conversion period

period

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30

Measured volume is obtained by inventory. Desirable volume is
estimated by summation and discount of normal yield table values.

The conversion period is the estimated number of years required to
bring net growth up to the estimated potential level for the desired
volume of growing stock and anticipated intensity of management.

Its length is based on such items as relative area of virgin, residual
and second-growth stands; proportion of total road system completed;
comparison of net growth in virgin, residual and second-growth stands
with the estimated potential growth rate for the types and sites under
consideration. The conversion period is ordinarily somewhat less than
a rotation.

The proportion of virgin old-growth in a working circle has a strong
influence in deciding on the period to use. For example, for a
working circle having 80 percent old-growth and 20 percent second-
growth by area and with a 125-year rotation, a conversion period of
about 100 years might be selected. Obviously, 80 percent of 125 years
equals 100 years. However, if the old-growth is fairly accessible
or can be readily made so, and if it has a thrifty, well-developed
immature understory it may be possible to complete the conversion in
a shorter period, say perhaps 80 years.

If, however, such an understory is largely lacking, and regeneration
and access are known to be extremely difficult, a longer conversion
period--perhaps 110 years--might be necessary.

Current growth and mortality is variously estimated by systematic
plot samplings, results of research studies, or yield tables--from
whatever source is judged best.

Preliminary estimates of allowable cut are supplemented by stand con-
dition class analyses and a recommended cut selected subjectively.

This approach focuses attention on growth and growing stock objectives,
and if properly controlled with systematic growth and mortality data
it should result in progress toward the goals selected, or in timely
revision of goals to more realistic levels.

In using the Austrian approach, it is important to remember that only
one of the four independent variables in the formula is based on
direct measurement, i.e., present volume. All the estimates of future
growth and mortality, of desirable volume, and of the number of years
required to attain growth and growing stock goals are based on more or
less subjective assumptions.

Sustained yield management and computations of allowable cut thereunder
--some to be made far in the future--require assumptions about the
future. The important thing to remember is that estimates of future
growth and growing stock must be checked objectively and continuously
so that errors may be corrected promptly and abrupt impacts on cuts
avoided.

The particularly wide variations in precipitation with resulting wider
swings in tree growth and mortality in the ponderosa pine region could

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31

lead to ^gross errors in estimates of future increment in this area,
necessitating drastic changes in the volume of timber cuts possible
in the future. In some working circles more than 75 percent of the
anticipated future cut is expected to come from wood predicted to be
grown between now and the time of harvest. Such predictions need to
be checked as soon as possible and in succeeding decades thereafter.

Since about 1940, precipitation and tree growth rates in the pine
areas have been generally above the long-time average. Thus, there
is a probability that succeeding decades may bring something less
than average precipitation and less than average tree growth. If
so, future cuts will need to be reduced below what would have other-
wise been possible.

Application of sanitation-salvage, regeneration, improvement and other
conditioning cuts are well underway in the western pine region national
forests. Thus, it is high time to supplement the Austrian approach
to regulation with a systematic analysis of trends in diameter distri-
bution and spacing under management. Results of such study will soon
be urgently needed to identify possible deficiencies in growing stock
structure, to prescribe management measures to relieve them, and
further to increase growth. This should be a logical early coopera-
tive project for National Forest Administration and Research.

Many of the future growth and mortality predictions in management
plans for the western national forests are based on assumptions of
increasingly intensive management practices not yet realized. Stand
improvement, recovery of mortality and similar measures to increase
growth must be intensified and accelerated if predicted yields are to
be achieved. This is an added reason why objective measures of
growth actually obtained are urgently needed. If management practices
actually applied are found to be more effective than anticipated, the
allowable cut should be appropriately increased; if less effective,
management will have to be further intensified or the cut reduced
accordingly.

Cut for Modified Timber Use Under Multiple-Use Management

Recent and increasing application of multiple-use forest land manage-
ment presents new and important considerations in the determination
of the allowable cut on the 42 western national forests. At present,
approximately 6 percent of the total commercial forest land area,
exclusive of formally established wilderness, wild areas, etc. , is
estimated as under varying degrees of timber harvest restriction.

The proportion of area affected is naturally highly variable in
particular situations and the total area is expected to increase.

These restrictions are applied to roadside strips, scenic or land-
scape areas near roads or recreation areas, and related designations
made in multiple-use area plans.

At present, policies and practices on the ground are in the process
of being defined and clarified; this is a new and developing situa-
tion. Complete restriction of cutting is seldom desirable; all areas
need to receive management to preserve the values for which they are

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32

designated. The basic questions are what kind of management and
specifically what cutting practices should be applied. It is also
recognized that modifications in timber use that necessitate appli-
cation of methods different from those practiced on unrestricted
timber use areas inevitably will increase timber management costs.
Governing policies and practices should be established as soon as
possible on a reasonable and realistic basis.

Current practices on the western forests are as follows;

Region 5. Annual cut is set at the equivalent of net
current periodic increment. Since the stands involved
are predominately overmature, this is but a fraction
(sometimes less than a fifth) of the mean annual incre-
ment. Obviously, it is not practically possible to
prevent decadence at this rate of treatment. Unsalvaged
mortality losses and a long-time trend to less pleasing
landscapes may be expected.

Region 6. Annual cut is set at the equivalent of gross
periodic increment. The reasoning which supports this
basis is that such cutting will approximately maintain
the existing level of growing stock but gradually sub-
stitute younger and healthier stands for those now
existing.

Region 1. Annual cut is set at the same rate developed
for the general commercial forest area. This assumes
that modifications of methods of cutting and logging,
and of sale timing, layout, and cleanup will suffice
without affecting the rate of regeneration cutting.

The assumption appears sound for Region 1 conditions
and in time may be for conditions elsewhere.

To minimize the likelihood of parts of these areas being withdrawn
entirely from commercial timber production, it is considered desirable
in Regions 5 and 6 to convert old-growth timber in modified timber use
areas at a rate somewhat slower than that adopted for areas where
landscapes are less important. To provide for this, additions to
rotations (up to a maximum total of 160 years) were suggested in the
Forest Service Handbook instructions of February 27, 1962. This
approach has not yet been tried.

It is difficult to establish any rotation as such for the management
of modified timber use areas. Conditions are variable and, in the
main, some form of partial cutting is appropriate at least for the
present. Ultimately, regeneration will be necessary and this may
require heavier cuttings in some areas than would be applied under
a selection system. In any event, cuttings should be applied in
such a way--selectively, in small patches, strips, or shelterwoods--
as to be consonant with the land use purposes of the areas
designated.

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The Board, believes that basing allowable cut estimates on growth is
a sound approach that gives sufficient flexibility to meet local
needs. Gross periodic increment will, as pointed out, result in
maintenance of healthy and durable stands and appears a desirable
basis. Net periodic increment will permit very little cutting in
old-growth stands, which average little net growth, and appears very
conservative as an average base. It should be applied only where
specific conditions require.

The Board believes strongly that policy and practice regarding cutting
on modified timber use areas should be faced squarely. At present,
there seems to be a tendency for forest resource managers on the
ground to avoid cutting in such areas because of uncertainty as to
policy and procedure.

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CONCLUSIONS AND RECOMMENDATIONS

The following conclusions and recommendations are not made in any
order of priority. In general, they follow the sequence of supporting
development in the body of the report.

1 . Size of Working Circles

The Board believes that the enlargement of working circles
has contributed constructively to a more rapid development
of national forests and their contribution to the western
forest economy. It believes that the Forest Service should
carry out its plans to further combine smaller working
circles into larger planning units. The Board recommends
continuing study of opportunities for additional improve-
ments in the geographic areas for which allowable cuts
are calculated, and it recognizes that improvements may
not always involve increases in working circle size as
management becomes more intensive.

2. Road Financing

The present method and level of national forest road
financing leads to some advance reading but fails to
make adequate provision for a rate and direction of road
development which will provide for maximum utilization
of the national forest timber resource and its growth.

It tends to preclude proper management of young growth.

It leads to inefficient utilization of accumulated salvage
and mortality losses, and delays conversion of the least
productive timber stands to more productive second
growth. In allocating the allowable cut to species,
grades and locations, it sometimes leads to conflicts
between the road objectives of the Forest Service for
developing the national forests and the demands of
forest industries for an optimum economic log supply.

The Board recommends that both the level and flexibility
of road financing be substantially increased so that the
reading program can be geared to the optimum development
of the total timber resource rather than being undesirably
limited to harvesting the allowable cut where the timber
harvested is able to bear the cost of road construction.

3 . Study of National Forest Contributions to the Western
Timber Economy

The Board recommends that the Forest Service continue
objective and quantitative studies of the economic role
of national forest timber management in terms of several
alternative input levels and several alternative harvest
plans and schedules and to evaluate the advantages and
disadvantages of such alternatives to the national and
regional economies.

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4 . ' Future Utilization

The Board recommends that the goals of national forest
timber management include definition of desired tree
diameters and grades for the final harvest cuts which
will be made after the conversion of over-rotation age
timber. Substantial study will be required.

5 . Intensification of Forest Inventories

The intensity and quality of effort channeled into
modern inventories for the 42 national forests under
consideration have been greatly increased in the past
six years. This effort will need to be continued and
intensified in the five-year period ahead, with special
emphasis on obtaining growth information from the semi-
permanent samples established during the initial
inventory, and on obtaining supplementary area-by-area
information on operability, accessibility, and local
silvicultural conditions.

6. Growth Prediction

New techniques of predicting growth for both managed
and unmanaged stands should modify, supplement, or
replace existing methods as soon as actual analysis of
semi-permanent growth and mortality samples indicate
superiority with respect to reliability or applicability,
prediction of growth and mortality on individual samples
by several methods in advance of remeasurement will
provide the only objective evaluation of current or
proposed techniques. Feed-back after remeasurement
will improve initial estimates of growth parameters
wherever growth has been expressed as a function of
structure.

7. Sample Tree Measurement

The four national forest regions involved should make
renev;ed efforts (including consultation with other
agencies, public and private, other Forest Service
regions, and research personnel) to test or adapt a
sample tree measurement procedure (employing optical
dendrometers and electronic computers) that will serve
both as a more satisfactory basis for control (i.e.,
depletion) in management planning, and as a more
efficient basis for sale than log scaling.

8, Units of Measure

The Forest Service should undertake on an orderly
nationwide basis, such steps as it deems necessary to
change its primary units of measurement in inventory
and sales from board feet or cubic feet alone to cubic
feet of volume, square feet of circumferential surface.

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36

and lineal feet of J.ength, These three objective and
relatively invariant measurements apply to both standing
or felled timber, are individually additive or accumulative,
and contain the basic information as to volume, size, and
rate of taper needed in appraisals and for conversion
into a wide variety of product yields with any specified
utilization or processing standards.

9 . Inventories Designed for Timber Management Planning

Progress in coordinating national forest timber manage-
ment planning inventories with Forest Surveys has been
good, and on the whole, beneficial. Where present Forest
Survey procedures are not well adapted to the needs of
management planning, renewed efforts should be made to
revise or else supplement them to incorporate the desired
features. Timber management planning should never be
shackled (for the sake of uniformity) to designs or
procedures not well adapted to achieve its objectives.

10. Utilization of Thinnings and Other Timber Not Now
Included in the Regulated Annual Cut

The Board recommends that the Forest Service continue
and strengthen its efforts to develop accessibility, uses,
and operating methods that will increase the value of the
potential timber harvest of thinnings and other timber not
now included in the regulated annual cut as an economic
industrial raw material. Such utilization represents an
opportunity to increase future allowable cuts, more nearly
capture the growth potential of the forest, and to reduce
misunderstandings about allowable cut figures and the
supplementary cuts possible where conditions permit on
the national forests.

11 . Regeneration Period

An allowance for the time necessary to establish reproduc-
tion following final harvest cutting must be included in
the regulatory rotation to provide that timber of the
average desired cutting age is produced. The length of
this regeneration period can only be determined by
experience on the ground and local conditions vary
greatly. Systematic and objective methods should be
applied to measure the establishment of reproduction
following cutting. This information, with appropriate
standards for what is adjudged to constitute acceptable
regeneration, should be used to revise the regeneration
period as the results warrant.

12. Modified Timber Use

A timber harvest should be taken from modified timber
use areas (designated for scenic, landscape, or related

M-1299

37

purposes) to maintain the forest values for which they were
designated and to prevent wastage of a utilizable resource.
Governing policies and procedures should be established and
applied as soon as possible to effect coordination betxjeen
multiple-use objectives and reasonable timber harvest. In
determination of planned yield from these areas as a part
of the regulated allowable annual cut, the Board suggests
a cutting control set at either (1) the same rate used
for the principal cut, or (2) the equivalent of gross
periodic increment. Choice of control and methods of
cutting applied should depend on needs in local situations.
Continued test and study of cutting prescriptions should
be made.

13. Forest Service-Customer Communication

In its contacts with industry people the Board encountered
comments and criticism regarding communication with the
Forest Service regarding timber matters. There was
feeling that operators, association representatives,
etc. , were not given timely and adequate information,
particularly on the initiative of the Forest Service,
about road construction plans, allov7able cuts and
changes being made, availability of management plans,
changes in policy and practices of timber cutting, etc. ,
that deeply affect them. The Board cannot assess this
matter quantitatively or in detail but considers it
important- -and also recognizes that there are two sides
to such matters. The Board commends work that has been
and is being done to give concerned people timely timber
business information and believes that this work should
be emphasized and strengthened.

14. Personnel Experience and Stability

The Board received a number of comments from several
quarters to the effect that a substantial part of
Forest Service-user difficulties that have developed
are a welling-up of instances of one sort or another.

In large degree they stem from lack of experienced men
on the job, disruptive personnel transfers from a timber
user standpoint, pulling off men for other national
forest work, and related reasons. This is not a new
problem and is well recognized within the Service.

The necessity of meeting forest exigencies and the
nature of multiple-use management is also appreciated.

The Board would stress, however, the importance of
maintaining strong and attractive career ladders in
a major functional use, as is timber, to minimize user
difficulties .

A deeper reason, as regards timber use, is that
knowledge and experience concerning the establishment,
protection, and manipulation of forest cover centers

M-1299

38

in the timber management group. This knowledge is
requisite to the effectuation of most forest land
uses .

15. Object-ve and Well-understood Standards and
Procedures for Allowable Annual Cut Determination

In the body of the report and in the recommendations a
number of references to objectives and standards have
been made :hat the Board wishes to pull together in a
general scatement. In such things as inventory work,
growth measurement, regeneration period, and determina-
tion of the cut as presented in timber management plans,
every effort should be made to lay things clearly and
objectively on the line so that they will be understood
by the timber user. If standards and procedures are
well understood and on a measurement basis, then changes
as indicated by the data should also be better accepted
as plans are periodically revised.

16. Attainment of Current /allowable Cut Objectives

The Board has been fully advised and has had opportunity
to consult with the Forest Service regarding current
action being taken to increase allowable annual cuts to
be reported to the Secretary of Agriculture by October 15.
As stated on page 26 and elsewhere in this report, the
goal of making projected annual cuts a reality in terms
of operable timber sales represents a considerable act
of faith in what the future will bring. Allowable cuts
calculated now envisage a substantial increase in
future intensity of timber management. To achieve
this intensity, strong and continued financial support
of the National Forest Program is necessary.

M-1299

fO«TY-TWO iUTlONAL FORiiSTS

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In addition to the totals ahova* R*6 approximately $4*282 M timber receipts aod $4*283 M total receipts from 0 & C and Warm Springs lands administered by the

Forest Servlcep These areas aire included in allowable cut calculations*

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5

1

i

i

Vt

H

s

1

?

A

1

9

I

H

s

-

-

VA

a

41Xowabl* out given as of January 1 prsoeding beginning of aacb fiscal year as sales ar© financed and p’ograinBied on tnis basis for tbe following fiscal

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