Guide to the Blacks Mountain Experimental Forest :a sustained yield experiment in ponderosa pine in northeastern California.

Historic, Archive Document

l

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

UNITED STATES

DEPARTMENT OF AGRICULTURE
LIBRARY

BOOK NUMBER

1.9

F7626G
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CALIFORNIA FORESTAND RANGE

EXPERIMENT STATION

FOREST SERVICE

U.S. DEPARTMENT OF AGRICULTURE

IK COOPERATION WIIH THE UNWERSETY OP CALIFORNIA
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THE BLACKS MOUNTAIN EXPERIMENTAL FOREST

of the

CALIFORNIA FOREST AND RANGE EXPERIMENT STATION—/

l/ Maintained by the

lh S. Department of Agriculture, Forest Service

in cooperation with the University of California

Guide to the

BLACKS MOUNTAIN EXPERIMENTAL FOREST
A SUSTAINED YIELD EXPERIMENT IN PONDEROSA PINE
IN NORTHEASTERN CALIFORNIA

U. S. Department of Agriculture
Forest Service

California Forest and Range Experiment Station
E. I. Kotok, Director

1938

THE BLACKS MOUNTAIN EXPERIMENTAL FOREST
A^ SUSTAINED YIELp EXPERIMENT IN PONDEROSA PINE
IN NORTHEASTERN CALIFORNIA

Contents

Page

Purposes of the Sustained Yield Experiment ... 1

The Experimental Forest . . . 2

Objectives of Management 4

Standard for Regulation 5

Silviculture . . . 6

Insect Control 7

Silvicultural Principles 7

Cutting System ... 8

Sanitation - Salvage Cut 9

Conversion Cuts 9

Stand Improvement 9

Fire Protection . . 10

Logging 11

Road System 11

Crews 12

Felling, Limbing, and Bucking 12

Yarding 13

Loading Trucks 13

Trucking 13

Loading Cars 13

Utilization 14

Records 14

- fi 8 19 I I

.

THE BLACKS MOUNTAIN EXPERIMENTAL FOREST
A SUSTAINED YIELD EXPERIMENT IN PONDEROSA PINE
IN NORTHEASTERN CALIFORNIA

Experimental forests, watersheds, and ranges are the field
laboratories in the research structure of the Forest Service. The
California Forest and Range Experiment Station maintains four ex-
perimental forests representing the more important timber types in
the Pine Region.

The Blacks Mountain Experimental Forest represents the
ponderosa pine type of California’s northeastern plateau, commonly
called "east slope" pine. The type occupies approximately 3,700,000
acres of which about 2,700,000 acres are virgin timber. Lumber is
the principal source of income from land in this type. A severe
climate restricts present agriculture to grazing of sheep and cattle.
Watershed values are of minor consequence because of low gradients,
pervious soils, light precipitation, and closed drainages. Recrea-
tional values are comparatively limited, being restricted to a few
areas of high scenic interest and to deer hunting.

The lumber from virgin stands is of exceptional quality be-
cause of uniform slow growth and great age of the timber, the better
grades competing successfully in markets throughout the country.

Poor site quality, reflected in slow growth, and prevalent insect
losses are features discouraging continuous forest management.

Heavy liquidation cutting now being practiced probably will seriously
deplete the virgin timber in 15 or 20 years.

PURPOSES OF THE SUSTAINED YIELD EXPERIMENT

A test of continuous forest management implies acceptance
of the hypothesis that conservative use of natural virgin timber
reserves over as long a period as possible is better social economy
than rapid liquidation. Management of a specific tract imparts
realism to the hypothesis through impelling choice of action in
the forest.

The principal aim of the project is to test the practical
value of certain theories of management, silviculture, and insect
control derived from disconnected studies since 1910. Such •
theories should be subjected to proving- ground demonstrations
before being recommended to industry or public land administrators.

Secondarily, the several research activities comprising a
field work center are given orientation and perspective by the
common aim, practical management of a forest.

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THE EXPERIMENTAL FOREST

The Blacks Mountain experimental forest is located about 40
miles northwest of Susanville and about 35 miles north of Westwood
in the Lassen National Forest. Susanville is the present milling
center for the Eastern Lassen Working Circle, of which this area
is a part. The location of the area with respect to highways and
to the Western Pacific Railroad is shown by the map on the back
cover. Reference to the more detailed map of roads and topography
(Figure l) shov/s the east boundary as about 7 miles, and the west
boundary about 1 l/2 miles from the Western Pacific Railroad and
the Susanville-Pittville highway toward which the topography in-
clines. Elevation ranges from 5600 to 6800 feet. All of the ground
is favorable for tractor and truck logging. The gross area of the
forest is 9826 acres of which 9094 acres are timbered.

The wood producing capacity of the soil and climate is below
average for pine sites in California. The rating in a 5- site clas-
sification is between 3 and 4. The average total height of domi-
nant trees at 300 years is 114 feet. The soil is derived from
lava, mostly vesicular andesite. Rock outcrops are numerous and any
soil disturbance, as in road building or skidding, turns up many
loose rocks and boulders. The soil itself is quite productive when
moisture is available, and it is probably the scarcity or lack of
precipitation during the growing season that accounts for the low
quality of site. Precipitation for the 1937-1938 season was 23
inches. Normally annual precipitation probably does not exceed
20 inches for this locality. Temperatures range from about 20° F.
to about 95° F.

The timber is largely ponderosa and Jeffrey pine, but with
some admixture of white fir and incense cedar on the upper slopes.
These latter species are more prominent in the young growth than in
the main stand. About 57 percent of the timbered area is fully
stocked with advance growth reproduction up to 60 years old. (Full
stocking is rated as 1000 trees per acre) . Brush is comparatively
light on all except 409 acres.

The stand is typically open with groupwise distribution.

These small groups tend to be even aged. About 95 percent of the
volume is in trees more than 120 years old. The tree of average
volume is 32 inches in diameter and 310 years old. Stocking is
estimated at only 38 percent of the normal capacity. This may be
explained largely by the poor representation of the thrifty inter-
mediate age classes - trees 75 to 150 years old.

2

Q

The following table shows the distribution of volume
(Scribner) by species:

Volume by species as of 1955-1954

Species

Total volume

Volume per acre

Percent

Board feet

Board feet

Pine

151,840,790

16,726

90.5

White fir

10,932,340

1,204

6.5

Incense cedar

5,032,807

554

3.0

Total

167,805,937

18,484

100.0

Quality of the timber is probably about average for the type.
Decay in pine, on the 240 acres cut over in 1937, resulted in a cull
deduction of 9 percent. Bark beetle losses have been high, averaging
203 board feet to the acre annually between 1933 and 1937. Present
growth is about 127 board feet, so there is a net loss of 76 board
feet to the acre annually in the virgin stand. Mistletoe infection
is not general, but is of importance in specific localities.

The area was approved and set aside as an experimental
forest by the Forester on March 28, 1934.

A 100 percent inventory of trees 3.6 inches d.b.h. and over
was completed in 1934. Along with the inventory detailed topo-
graphic and type maps were made, which afforded the basis for de-
ciding on location of roads and subdivision of the area into com-
partments or working units .

All construction work has been done by CCC labor under super-
vision of the Lassen Forest according to specifications drawn up by
the Experiment Station.

Road construction was started in 1934 and completed early in
1937, except for surfacing the main utilization road.

The forest headquarters are located along the county road for
convenience of visitors and because of proximity to the railroad and
the CCC camp at Halls Flat (1 l/2 miles to the north) . Improvements
completed to date include an office-laboratory, superintendent’s
residence, bunk house, tv/o small garages, a warehouse-garage, mess
hall, dormitory, pumphouse and tank tower, a 600-foot well, and a
5000 gallon underground water storage tank.

-3-

The entire experimental forest is divided into compartments
averaging about 100 acres each. These compartments are bounded by
roads and monumented lines. In most cases the lines were located
in such a# manner that logs could be skidded from any part of the
compartment to the road without crossing a compartment boundary.

OBJECTIVES OF MANAGEMENT

The objectives of management cannot be fixed with certainty
in advance. Future markets and growth after regulation must be
estimated. Certain hypotheses have been set up as goals to work
towards „

The product is to be ponderosa and Jeffrey pine saw timber.

The size of the operation under regulated yield may be fore-
cast approximately. It is desirable that the operation be large
enough for efficiency, remembering that efficiency cannot be judged
entirely by present-day lumbering standards. The poor site, expe-
rience with growth, and the area likely to be tributary to a single
plant, dictate a small operation. The output aimed for will be
50,000 board feet a day for 100 days, or 5,000,000 feet a year.

After regulation, the trees to be cut will range from 12 to
30 inches in diameter, with an average of about 20 inches. The
average tree in the stand will be 14 inches in the year after a
periodic cut. On this site such trees probably can be grown in a
rotation of 140 years. Same lumber of higher grades may be obtained
by pruning butt logs of the more promising dominant pines.

Cutting cycles, after regulation, will average 20 years.

During the conversion period cutting cycles must be irregular,
usually shorter than 20 years .

A forecast of growth indicates that not more than 150 board
feet to the acre annually can be expected after regulation. It
will be necessary to cut profitably as little as 3000 feet to the
acre. Gross income from growth will be about 2 l/2 percent a year.

The test requires operating at a profit within these narrow
margins .

It is proposed to manage about 8000 acres of the experi-
mental forest as though this area were a fraction of a larger working
circle capable of supporting an operation of five million feet an
nual capacity. Conversion cuttings in the merchantable stand will
extend over a period of 10 or 12 years. Stand improvement, insect
control, and fire protection will continue until the twentieth year.
The aim is to manipulate the present large valuable reserve over a
20 year period in such a way as to establish the elements of a regu-
lated stand and pay for improvements, cultural treatments, insect
control, fire protection, and administration.

4

A research program cannot be projected safely beyond 20
years. Obviously, a stand of this kind cannot be brought under regu-
lation in 20 years. It is necessary to have some standard against
which progress toward regulation can be checked by periodic measure-
ments. Such a standard has been set up from previous research, the
framework of the ideal regulated stand being shown in the form of
charts .

STANDARD FOR REGULATION

In setting up the ideal stand, the first item estimated was
the volume of the working reserve at the beginning of a cutting cycle.
Normal yield for selection stands of this character is indeterminate.

It' was necessary, therefore, to estimate the volume of the working
reserve from a recent yield table prepared by Dr. Walter Meyer. The
assumption was made that yield in a fully stocked selection stand
will be the same as yield in a fully stocked even- aged stand. Most
foresters hold the opinion that selection stands yield somewhat less
than even-aged stands. The yield table for site index 114 feet was
discounted to 80 percent, a customary allowance for deficiencies in
stocking. For the regulated selection stand with seven 20-year cut-
ting cycles, the working reserve was estimated by adding one-seventh

of the discounted tabular values for the six age-classes 0 - 20, ,

100 - 120, the sum being 5244 board feet to the acre.

The periodic cut was estimated at 2887 board feet by taking
one-seventh of the corrected yield table value for age- class 120 - 140.
The working reserve must grow at the annual rate of 144 board feet to
produce this cut in 20 years. It was necessary to approximate the
diameter and tree-class distribution of the reserve v/hich would main-
tain this optimum growth.

Analysis of Blacks Mountain and other selection stand records
has shown that when volume in board feet for the total stand, or for
a Region 5 tree-class, is plotted over diameter, a normal distribution
results. A normal distribution is described by the mean and the
standard deviation. In the desired distribution the mean of the stand
is fixed by capacity of the site and management objectives at 14
inches. It was necessary to assume that the standard deviation will
be the same as for natural selection stands. From published tables
for normal distributions, the proportion of the 5244 board feet ex-
pected in each diameter class was computed.

The proportion of the reserve in each tree- class was determined
from studies of selection stand structure, yield, and effects of cut-
ting. These experiments indicate that, by treatment control, it
should be possible to maintain 80 percent of the reserve in Class 1
(dominant) trees. Site and management objectives fix the mean of
these Class 1 trees at 20 inches. Taking the standard deviation for
this group in natural stands, the volume was allocated to the various
diameter classes. In a similar way the remaining 20 percent of the
reserve in Classes 2 and 6 (codominant, and intermediate and sup-
pressed) was distributed.

5

Since selection stand management requires individual tree
control, it was necessary to know the number of trees there should be
in each diameter and tree- class. Previous studies have shown that
when number of trees in the stand, or in a Region 5 tree-class, is
plotted over diameter, another characteristic distribution - the
J- shaped curve — results. Relying on this fact, the number of trees
were apportioned to the diameter classes in much the same way as
for volume. (Figure 2).

Independent support for the belief that this reserve stand
of 5244 board feet will yield the requisite 144 board feet annually
was sought in a recently prepared growth predicting mechanism for
selection stands. This yield predicting mechanism consists of
three alinement charts -- one for growth of trees 12 inches and
larger, one for those trees which become 12 inches and larger in a
20-year period, and one for losses. The first two charts indicate
that, in a stand of this type, the trees 12 inches and larger may
be expected to produce about 80 board feet to the acre yearly, and
the pole stand may contribute an additional 63 board feet, giving
a total gross growth of 143 board feet. The third chart indicates
that normal losses should average about 12 board feet, so that net
growth will be only 131 board feet to the acre annually.

These growth and loss predictions are founded on records
from stands receiving but a single conversion cut. The more inten-
sive silviculture contemplated should result in better growth rates
than estimated. On the other hand, losses are now abnormal, and if
the optimum net growth is to be maintained, there must be effective
insect control as well as intensive silviculture.

SILVICULTURE

In the method of cutting proposed in this area the idea
of single-cut lumbering and mere culling of stands will be aban-
doned, because this practice offers little hope of getting re-
generation, satisfactory growth, good quality, proper composition,
and control of brush and insects. It is recognized that intensive
silviculture is needed and that costs must be kept within the low
income from growth. Part of the income from the initial cuts will
be reinvested in the remaining stand with the intent of recovering
the investment from future crops. During the course of the study,
how much should be spent and what treatments will be effective
are to be determined, if possible.

6

VOLUME BOARD FEET PER ACRE

2,500

DIAMETER CLASS, INCHES

BLACKS MOUNTAIN EXPERIMENTAL FOREST

COMPARTMENT B 25-1

Figure 2

-6a-

Insect Control

\

One of the most pressing problems is that of insect control.

At the current rate of loss, every year?s delay in reaching an acre
results, on the average, in a gross loss of 203 board feet and an
estimated net loss of 76 board feet. A basis for selective risk
marking is needed when relatively large reserves of old timber are to
be carried as in the present experiment. A tentative basis for such
selection has been developed by the Bureau of Entomology and Plant
Quarantine during the past 7 years and is being adequately tested in
this area. These studies have shown that incipient broods of the
California flathead borer are present in a relatively large proportion
of the green trees. It is believed the continuation of conditions
adverse to the trees permits the larval broods to develop rapidly and
kill the trees or induces attacks by bark beetles. These incipient
flathead infestations are associated with deteriorative changes in the
needles and crowns of trees which can be detected for an, as yet,
undetermined period of time before the trees are killed. The Bureau
has prepared a tentative risk marking guide for this project, based
on appearances of the leaves and crowns of the trees. Four degrees
of risk are recognized. Salvage logging is directed to those areas
having the greatest numbers of high risk trees. Trees considered
doomed will be cut in advance of death and staining. If the supply
of highly susceptible trees can be maintained low enough, perhaps
bark beetle populations cannot gain sufficient strength to attack
more resistant trees in great numbers.

Silvicultural Principles

Previous studies suggest the following general silvicultural
principles for trial:

1. Cutting will be flexible with respect to time. (Figure 3)
Pine seed crops are infrequent, irregular, and so, are unpredictable
for more than a year in advance. Only good crops are of much impor-
tance in restocking because rodents and many other agencies overtax
light sporadic yields. There should be openings free of competition
and with exposed soil, coincident with seed fall. If logging pre-
cedes the seed crop by more than two or three years, brush and weeds
often usurp these favorable openings. An effort will be made to
time cutting by observing seed crops a year in advance of seed fall.
Just as good germination will be sporadic, so will release of repro-
duction come due at irregular, though less compelling intervals.

Large reproduction approaching merchantable size- limits will be re-
leased first. Frequent returns to the same acre are necessary to
maintain uniform growth (volume and quality) of light demanding
trees in selection forests. Insect damage occurs sporadically.

The hypothesis of salvage- control requires anticipation of killing
and staining of timber and the build-up of broods. In deference to
management, it must be recognized that the market is variable.

Since the stands are not uniform in quality, there must be freedom
to select what is wanted currently. Priority in timing cutting will
follow the order of needs for insect control, for release, for
seeding, and for quality of product.

7

Figure 3. Mature ponderosa pine stand without advance growth.
A series of light cuts will be made when good seed crops are
ripe in order to make conditions favorable for establishment
of reproduction o

Figure 4. Pruning will be started in trees of pole size when
dead limbs extend up the bole 6 feet or more. Under future
management the 31 inch tree to the right will be the maximum
size grown and the butt 32 feet will ‘be’ free of dead limbs and
surface knots. -7a-

2. Cutting will be flexible with respect to area. Seed
crops usually do not occur simultaneously over large areas. Advance
growth is irregularly distributed and new reproduction may be ex-
pected to occur in the same way. It follows that preparatory seed
and release cuttings must be irregularly spaced over the area.

Insects have a tendency to attack trees in groups, and the intensity
of damage is seldom uniform over large areas. The brush hazard is
not uniform. Similarly, the quality of timber varies from place to
place. Area priority will be in the same order as for time.

3. Cutting will be flexible with respect to the volume
removed. Where advance growth is absent, the first cut will be light.
Where there is no reproduction and brush is present, only those trees
rated highly susceptible to insect attacks v/ill be cut. The light
reserve stands left In single-cut lumbering produce too little seed

to effect prompt restocking. A light initial cut should provide
openings and insure a greater seed supply. Where reproduction is
already established, moderate to heavy release cuttings will be made,
regulated by the age, stature, and density of the advance growth.

In the first salvage cut, the volume removed will vary with the
occurrence of trees highly susceptible to insects.

4. Tree selection will be based on an insect risk rating,
Region 5 tree classes, and new Region 5 log grades. Trees which can
never be merchantable because of species, form, or disease, will be
removed as a stand improvement measure where future crop trees are
affected adversely.

Cutting System

The selection form of forest has been adopted for this trial,
a fact already apparent from the text. Some may have doubts as to
the wisdom of this attempt to maintain a light- demanding species
like ponderosa pine in the selection form. In support of this deci-
sion, it should be explained that the grouped arrangement of age
classes will be sought, — - a form most frequently assumed by natural
forests. Also, the possible shade- enduring invaders, white fir and
incense cedar, are at the disadvantage of being near the limits of
their natural distribution and should not be very troublesome here.
Brush promises more difficulty than the minor trees, and selection
treatments seem best adapted to its control. A cogent factor in the
decision was the belief that bark beetle infestations are less
likely to reach epidemic proportions in selection stands.

-8

Sanitation - Salvage. Cut

The first cutting treatment, begun in September, 1937, is de-
signed for salvage insect control. The aim is to cover in 2 to 4 years
the portions of the area with accumulations of high risk timber. This
rapid coverage required a tentative decision as to the lightest cut
which could be logged economically where the volume is widely dis-
persed. There was no similar lumbering experience to draw upon. The
cut being tried is a minimum of 2500 board feet to the acre. Advance
surveys indicate that this volume usually will include all the high
risk trees « V/here the volume of high risk trees falls below 2500
feet, enough good risk trees of highest quality are being marked to
make up the deficit « When defect is encountered, additional trees are
marked to keep the net volume up to this figure. In 1937 the cut
averaged 2604 board feet to the acre, or about 14 percent of the stand.

This salvage- sanitation treatment probably will have no appre-
ciable effects on growth rates in the remaining stand, or on restocking.

Conversion Cuts

Subsequent silvicultural cuttings will be based on the princi-
ples outlined above . Marking will be guided by detailed maps showing
the status of reproduction and brush in each compartment, and by
stand graphs showing for each compartment the current stand structure
and the ideal stand to be approached.

These conversion treatments obviously will result in varied
reserve stands, some light and some heavy. The decadent condition of
the timber indicates that by the end of 12 years, reserve stands
probably should be reduced to about 20 to 25 percent of the original
volume. This will be accomplished in from one to three cuttings.

The cut, of course, also will be variable. The inventory
data indicate that a fairly uniform output from the area as a whole
can be maintained. The most uncertain elements are insect control
and the occurrence of reproduction. When cutting for these two
essentials does not provide a sufficient monthly or seasonal output,
the deficit can be made up by cutting to release advance growth in
which there is considerable option as to time and area.

Stand Improvement

Reference to earlier growth estimates shows that 63 board feet,
or 44 percent, of the expected growth must come from small trees
largely present as advance growth. Growth of these trees to mer-
chantable size must be hastened if the gap between conversion and re-
gulated cuts is to be shortened. (Figure 5) Thinning experiments
show that progress cannot be left to Nature, and that the harvest cuts,
alone, will not be sufficient. Over limited portions of the area, fir
and cedar advance growth must be kept in check. Thinning will be de-
signed to release the number of crop trees indicated as desirable by
the stand graphs.

-9

Figure 5. An excellent pole stand which has developed in an
opening free from competition with the old stand. Crop trees
will be selected and pruned to produce butt logs of high quality.
Saplings in dense stands under an overstory of mature trees may
be expected to develop into stands such as this following release.

- 9a

Recalling that the average tree cut can be only 20 inches in
diameter, it appears necessary to prune first logs of the most pro-
mising young dominant pines. (Figure 4)

To prevent further seeding in of fir and cedar, the few larger
trees of these species will be cut. Most of these trees are unmer-
chantable because of decay. Some of the cedar will be yarded in tree-
lengths to roadways and made into fence posts. The other trees, in-
cluding pines with no present or future value, will be felled and
lopped in place.

Stand improvement will be performed as a separate operation
independent of logging. An attempt will be made to use unskilled
labor not employable in logging, and to extend the work season for
loggers over periods when such workers usually would be idle. No
stand improvement has been done thus far. Probably such work will
be limited to special experiments large enough to determine costs
and silvicultural effects.

Fire Protection

A special plan for protecting the experimental forest from
fire is in operation. General protection is provided by the local
District Ranger ?s force. During periods of extreme fire danger, a
lookout within the forest will be manned. The visibility map dis-
closes that three regular lookouts see parts of the area, but are
too distant for intensive protection. A telephone line is under
construction to connect the lookout with headquarters. Radios main-
tain contact between lookouts and woods crews. Utilization roads
permit convenient access to all parts of the forest. In addition to
these roads, one to three permanent main skid trails in each 100-
acre compartment serve as firebreaks. A tank- truck of 1100 gallons
capacity, with pump attached, serves the dual purpose of road
sprinkling and fire suppression. Smoking restrictions conform to
rules in effect on Region 5 timber sales.

Slash from the present light sanitation cut is being left
in place. Tops and unmerchantable trees are lopped. When heavier
cuttings are begun, the system of partial piling and burning slash
will be followed.

Snags are numerous. In some places insects have killed
trees at the rate of 600 to the section in a single year. (Figure 6)
Many of these dead trees have fallen from natural causes. To fell
the many now standing would interfere seriously with a type of log-
ging that requires repeated cuts. For the present, snag disposal
is confined to roadways and main skid trails. Snags which are a
menace to yarding crews are felled in advance of logging. After
the final conversion cut is made, snags still standing will be cut.

-10-

Figure 6. Losses from insects averaged 203 board feet per acre
annually between 1933 and 1937. These losses are continuing in
the uncut stands. The accumulation of snags constitutes a
serious fire hazard.

Figure 7. The "V" notch blaze shows the CCC felling crew the
direction the tree is to be felled. Avoidance of damage to re-
production and direction of skidding are the main considerations
here.

-10a

.

1! • 1

LOGGING

The tractor and truck system of logging is being used. All
woods operations are performed by Federal employees with Government
owned equipment. Research cannot be scheduled far enough in ad-
vance to permit equitable contracts with private loggers.

Road System

Flexibility in cutting with respect to time, area, and
volume required advance construction of a road system. The loca-
tion, mileage, and standards could not be determined entirely by
the present virgin stand. The roads must be adapted to future,
lighter and less valuable cuts, as well. It was assumed that roads
meeting the requirement for logging would be sufficient for protec-
tion and administrative needs. The mileage that would be efficient
would depend upon construction and maintenance costs, and the rela-
tive costs of tractor and truck hauls where loads would be more
widely dispersed than in one-cut operations of today. Again esti-
mates had to be made subject to confirmation by study.

Location was determined entirely by topography and capacity
of the land to grow merchantable timber. Paper locations were
made on a map which showed 10 foot differences in elevation, bar-
riers to logging, and fail places. From office notes, a trial
ground location was made and adjusted later to the final line,
where construction difficulties were encountered. Compartment
boundaries were made to conform to the roads in such a way that
the timber in any compartment can be yarded downslope without dis-
turbing any other compartment. To facilitate protection, par-
ticularly, most of the roads are inter- communicating to avoid
culs-de- sac .

Mileage was determined by setting the standard of 2000
feet as the maximum tractor haul. There was definite intent to
set mileage higher than would be necessary in standard logging in
order to include the maximum study might show to be efficient.

If portions of the system do not pay, they can be omitted from
cost figures. The road system amounts to about 47 miles.

Roads are of three standards. The main road of highest
standard extends from the railroad and county highway by the
lowest route through the middle of the forest for about 7 miles.

The road is cleared to a width of 22 feet. The tread is 13 to 15
feet wide. The road is now being surfaced with fine crushed rock
over a coarser crushed rock base 8 inches thick. Turnouts are
125 feet long and 24 feet wide for a distance of 75 feet. Curves
are limited to a radius of 60 feet. There are no adverse grades
and the maximum favorable grade is only 5 percent for about one
mile. Construction cost about $5000 a mile.

-11-

Three secondary roads have a total length of 12 miles. These

are cleared to a width of 18 feet. The tread is 11 to 12 feet wide

and is unsurfaced. Curves have a minimum radius of 60 feet. Grades

are all with the load, the maximum being 10 percent for 750 feet.

Construction cost approximately $2000 a mile.

Tertiary roads number 23 with a total length of 28 miles.
These are cleared to a width of 16 feet, have 10 to 12 foot treads,
and curves of 50 feet minimum radius. They are unsurfaced. Grades
are limited to 10 percent with the load and 5 percent against the
load. They were simply constructed by ripping, rock picking, and
blading to make easy travel for trucks with pneumatic tires. Con-
struction cost about $800 a mile.

All truck roads were constructed by Civilian Conservation
Corps labor.

In addition to the truck roads, one to three permanent
tractor trails are opened into each compartment by confining the
larger tractor to the predetermined locations in logging.

For road maintenance a motorized patrol is used. To repair
surfaced sections, a stock of crushed rock is being made by a
crusher in the forest. Sprinkling unsurfaced roads has not been
necessary thus far, so the sprinkler truck has been constantly
available for fire suppression.

Crews

At the present time, all members of the logging crew are
Civilian Conservation Corps men, except the foremen. A technical
forester is in general charge of all operations in the experimental
forest. An experienced logging superintendent has direct charge of
woods operations. There are three experienced foremen - - a bull-
buck, a truck landing boss, and a top- loader at the railroad.
Maintenance and servicing of equipment is handled by contract with
the Forest Service Redding Shops, a head mechanic being stationed
on the operation.

Felling, Limbing, and Bucking

The trees are marked for insect risk by a resident entomolo
gist of the Bureau. A technical forester marks the trees for cut-
ting, log- grades each tree, and indicates the most desirable direc-
tion of felling. (Figure 7) Because the trees are necessarily scat-
tered, he also prepares a rough map for the woods foremen, showing
the location of each marked tree, the main skidding trails, and the
landings .

Hand tools of the usual kinds are used in felling, limbing,
and bucking. Limbing is done where the tree falls, except that
those limbs on the under side are removed after the tree is yarded to
the main trail. Bucking is accomplished at the main skid trails.

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Yarding

Present equipment for yarding consists of one 64 horse-power
semi-diesel tractor with single drum and arch, and one 96 horse-
power diesel tractor with single drum and arch. Trees are yarded,
full length, with the smaller tractor to the main skid trails where
they are spotted for bucking, inclined toward the landing. The
larger tractor is confined to hauling along main skid trails to
landings. This system permits large loads and reduces damage in
the reserve stand to a minimum.

Loading Trucks

Loading the trucks is a crucial operation in present light
sanitation logging. Landings are necessarily small and moves are
frequent. The loader must be mobile, yet powerful enough to handle
large logs. No suitable standard equipment was available. The
loading equipment being tested consists of a two-wheeled industrial
crane with a live boom, attached to the rear of a 62 horse-power
diesel tractor fitted with two drums. This crane is furnished under
cooperative agreement by the Le Tourneau Company. The company made
minor changes to adapt the crane for logging after first tests in
1937. (Figure 8) A report on this piece of equipment will be pre-
pared at the end of this season.

The tractor used in loading is equipped with trail-builder,
and serves to clear landings of numerous rocks unearthed in road
construction, to make turn-arounds, extend spurs, and for standby
yarding.

Trucking

Hauling equipment consists of five trucks with trailers
with load capacities of 3000 board feet, and two trucks with
trailers capable of hauling average loads of 4000 feet. At the
present time the logs are being hauled an extra 22 miles over the
county road to the Fruit Growers Supply Company logging railroad,
because arrangements have not been completed for hauling over the
nearby Western Pacific. (Figure 9)

Loading Cars

Logs are unloaded from the trucks and loaded on cars with a
50 horse- power, two- drum, diesel winch. Two poles are used to
permit decking in case cars are not always on the spur.

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Figure 8. Loading a 32- foot log with the Le Tourneau industrial
crane. Mobile loading equipment , making frequent moves to new
landings feasible, is essential to the Blacks Mountain method
of cutting .

Figure 9. Railroad landing at the Fruit Growers Supply Company's
Feather Lake spur. The truck haul is 22 miles.

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I

Utilization

The standards for utilization are about the same as for cur-
rent Forest Service sales. The logs are cut to 32-foot lengths
whenever possible. Because of expected prevalence of incipient in-
sect attacks in this sanitation cut, stained logs are not sent to
the mill by special agreement with the buyer. But little stain has
appeared thus far. Scaling follows standard Forest Service procedure.
The daily output is about 30,000 feet in six hours, at present. The
timber averaged about three 16-foot logs to the thousand board feet
in 1937.

Sale of logs by grades is planned, after a period of study
to determine reliability of a new grading system, and feasibility
of this method of marketing.

RECORDS

The Blacks Mountain project has two aspects of interest with
respect to general research methodology. First, it exemplifies the
principle that theories derived from small scale, often disconnected,
laboratory -type of studies should be put to a proving -ground test
before they are recommended to forest administrators. In the second
place, it exemplifies the conviction that the several studies at a
field research center should have a common aim, namely, management
for the type of forest represented. This common aim gives realism
and practical orientation to research, not possible when the experi-
mental forest is used merely as a place for field plots.

The project has been discussed as a unit. Obviously, if ob-
servations are to take the form of independent measurements, the pro-
ject must be handled as a series of separate studies, each with a
definite plan and yielding results of independent value. This pro-
cedure minimizes the risk of complete failure and insures a con-
tinuing output of useful reports at not too lengthy intervals. The
numerous studies can be characterized only briefly by examples.

Comparison of different methods of cutting will be continued,
even though a special method has been adopted as most promising for
the major test. This year, and in each of the next nine years, in-
stallation of permanent plots will be completed to afford compari-
sons of Forest Service, modified Forest Service, and Blacks Mountain
methods of cutting, using a random block design.

Entomological studies by the Bureau, aside from the main
object of salvage control, should yield information on such questions
as to whether or not lack of control on one property jeopardizes
adjoining treated timber. Several compartments will be left in the
natural state in various parts of the forest.

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Utilization studies should result in improved log grade
standards, standards for grading standing trees, and costs of
operating standard equipment. Probably some new equipment will be
developed, or will be tested in the experimental forest, as has al-
ready been done with the loader mentioned.

Sampling methods, as may be inferred are receiving special
attention. Costs, particularly, must be representative and sound
if success is to be attained. A special study of administrative
costs will be made to determine the portion justly due to timber
management. Cost calculations will be made from the standpoint of
both private and public owner.

It is appreciated that operating costs, with present emer-
gency type labor, are not representative of standards of the indus-
try. An important aim of the CCC is to train men, and this purpose
requires frequent replacements with inexperienced crews. Inci-
dentally, it is safe to say that few other CCC activities have been
received with greater interest by the enrollees. It should be ex-
plained that most of the operations involved in logging have been
studied already, under standard conditions. The time units can be
applied to any cost structure. Important procedures peculiar to
this project will be studied by hiring skilled labor for periods
long enough to provide reliable samples.

Growth, loss, and stand structure changes, _ for the area as
a whole, will be determined by periodic sampling inventories.
Anticipating that ordinary cruising would not be efficient, and
that permanent sample plots would be too expensive, a study of
sampling methods was undertaken when the project was started.

A complete inventory of the forest was made by small units of 2 l/2
acres. With the total stand variance to check against, it is pos-
sible to determine what size, shape, or arrangement of sampling
units is most efficient for the most important attributes.

To detect changes assignable to growth, which may be as
small as 2 or 3 percent, it is necessary to exclude from periodic
comparisons the errors of sampling, which may be as large as 10
to 30 percent. To exclude sampling error, it is necessary to re-
locate the same units or plots, each period. An intensive control
survey makes this possible in the experimental forest.

It will be necessary to study tree attributes which change
with time, such as tree- class, or risk rating. Such comparisons
require that the tree- class groups contain the same trees at the
beginning and end of the period. It will be necessary to identify
individual trees by mapping, numbering, or both. Expensive as
this procedure may be, it is deemed essential.

-15

A by-product of this project is a report on sampling pro-
cedure by A A. Hasel, now awaiting publication. The paper has an
important bearing on cruising, larger forest surveys, and similar
work.

In conclusion it may be said that those responsible for the
Blacks Mountain project are burdened with no illusions of simplicity
of the many problems involved. Experienced counsel is being sought
from forest administrators, lumbermen, engineers, and other groups.
(Figure 10) A considerable number of persons and agencies are co-
operating wholeheartedly to make the undertaking succeed. Interested
criticism is most welcome.

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ORGANIZATION CHART

BLACKS MOUNTAIN SUSTAINED YIELD PROJECT

figure 10

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