PRACTICAL FORESTRY IN THE PACIFIC NORTHWEST PROTECTING EXISTING FORESTS AND GROWING NEW ONES, FROM THE STANDPOINT OF THE PUBLIC AND THAT OF THE LUMBERMAN, WITH AN OUTLINE OF TECHNICAL METHODS
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trees of both redwood and other species and the maximum protection
of all from fire, should then be the means employed. On some tracts
the proportion of redwood will not warrant this effort; on some
it is not even required. The question of whether it pays to hold
redwood land is therefore almost wholly local, but when conditions
are favorable it can be answered affirmatively, because of the
extremely rapid growth, with less doubt than of almost any other
species.
There is some tendency to over-production of sprouts by redwood
stumps. Removal of the excess with an ax, saving those closest
to the ground and not over-thinning to the extent of reducing the
density conducive to height growth and shedding of low branches,
improves the chances of those remaining.
SEEDING AND PLANTING
SEED SUPPLY
It has been shown in a previous chapter that the owner of deforested
land who desires to secure a second crop may find it necessary or
cheaper to adopt artificial measures wholly or in part instead
of depending upon natural reproduction. These measures may be of
two kinds--direct seeding, in which the seed is sown where the
trees are to stand permanently, and the planting of trees grown
in nurseries.
Whether artificial reforestation is accomplished by means of sowing
seed or planting trees, the first requisite is a supply of tree seed
of the desired species and of good quality. Unfortunately for the
timber owner who wishes to enter upon extensive seeding operations,
the business of collecting and preparing forest tree seed for market
has received but little attention from old-established seed firms,
and it is not always possible to purchase the species and quantity
desired. Moreover, the prices charged are often excessive.
In the Pacific Northwest, however, the demand for seed of Douglas
fir and Sitka spruce has led to the establishment of a considerable
trade in these species, and at reasonable prices, so that where
these species are to be used, or only small quantities of other
species, the timber owner will probably find it to his advantage
to purchase the seed rather than to attempt collecting it himself.
Douglas fir seed is quoted at $1.40 to $2.00 per pound and Sitka
spruce seed at $2.25 to $3.00.
In purchasing seed it is common practice to specify that it shall
be of the new crop, because tree seed kept in ordinary storage
loses its vitality materially. When properly stored in air-tight
receptacles, however, as is now done by some seed dealers, it will
retain its germinative power for several years with only slight
depreciation. Moreover, fresh seed, if improperly treated, may
be of very poor quality, so that the age of the seed is of little
value in the determination of its worth and the only sure method
of ascertaining this is by means of germination or cutting tests.
The latter method is the quickest and most simple and consists
of cutting open a number of the seeds and ascertaining the per
cent whose kernel is sound, plump and moist. Seed of good average
quality should contain not more than 25-30 per cent of infertile
seed.
When seed cannot be purchased, it is necessary to collect. Since
no species of coniferous trees bear abundant crops of seed each
year and often several seasons will elapse between good crops, it
is necessary to gather sufficient seed when the supply is abundant
to provide for succeeding years when the crop is apt to be a failure.
The seed ripens in the fall, usually during August or September,
and the cones should be collected at that time. Pines require two
years in which to mature the seed; that is, the cones are not fully
formed and the seed ripe until the second fall after the fertilization
of the flowers in the spring. Most of the other important conifers
ripen their seed in the fall of the same season. Shortly after
the seed is ripe, the cones open and allow it to disseminate,
consequently they must be gathered before this occurs.
The cones are gathered either by climbing the trees and cutting
them off from the branches, by picking from the tops of felled
trees, or by robbing squirrels' hoards. Where squirrels are abundant
in the forest, the last method is the cheapest. Climbing trees
is practiced only where the trees are small. When this method is
employed, the workmen should be equipped with linemen's belts and
climbers. Picking from felled trees is readily carried on except
where dense underbrush interferes, as is the case in the ordinary
Douglas fir forest.
Trees growing in the open, with large crowns extending down the
greater part of the bole, bear cones more abundantly than trees
in dense forests, and for this reason collecting from scattered
open growths can be done more cheaply than on logging areas. Often
large quantities of cones can be purchased from settlers who will
collect and deliver them at central points at a stipulated price.
When this method is employed, however, frequent examination of
the cones should be made to ascertain that they contain the full
number of seed, for often opened cones from which a part or all
of the seed has been disseminated will be offered for sale. Insect
larvæ also often destroy a large proportion of the seed, particularly
when the crop is light and care should be taken that the cones
purchased are not infested. The prices paid for cones vary from
25 cents to 50 cents per sack for the larger cones, like yellow
and white pine, and 50 cents to $1.00 for Douglas fir and spruce,
depending upon the abundance of the crop.
After the cones are gathered the seed must be extracted and cleaned.
Where climatic conditions in the fall of the year will permit
air-drying, the cones may be spread out on sheets or blankets where
they will be exposed to the sun and wind. Under this treatment
they will open in from 3 to 6 days, depending upon the weather
and the species. Where bad weather will interfere with air-drying,
the cones must be dried undercover by artificial heat. This is the
method usually employed by professional seed collectors, and where
large quantities of cones are to be treated each year special dry
houses are constructed and fitted with elaborate drying apparatus.
The work can be done most cheaply with such an establishment, but
for the ordinary timber owner who expects to collect seed only
occasionally, a makeshift dry-house which will answer the purpose
can be fitted up inexpensively in any unused building. The essential
features are shelves or trays 4 feet wide arranged around the walls
of the room, one above the other and separated about 8 inches apart,
and a heating stove placed in the center of the room. The shelves
may be made of burlap stretched tight, or, better still, of wire
screening of 1-1/2 inch or 3/4-inch mesh.
After being subjected to a temperature not exceeding 110° Fahr.
for from 24 to 48 hours, the cones will open, allowing the seed to
fall out when shaken or pounded. The seed when separated from the
cones is then mixed with a coarse gravel in about the proportion
of 4 to 1 and churned to remove the wings. Finally, all foreign
matter is removed by screening and hollow seed blown out by passing
it through an ordinary fanning mill.
SEEDING VERSUS PLANTING
The selection of the method of reforestation to employ, whether
direct seeding or planting, depends primarily upon the character
of the area to be restocked. Direct seeding is usually considerably
cheaper when the results are satisfactory, but only on the more
favorable sites where moisture and soil conditions are right is
there any assurance of success. Even in such cases partial or total
destruction of the seed often results from birds and rodents. In
exposed situations where the soil is shallow, or where because of
climatic conditions soil dries out several inches deep during the
growing season, the seed may not germinate at all, or the young
seedlings may be killed before they have time to send their roots
down to the permanent moisture level. In such situations, planting
is the only reliable method. If the plant material is of the proper
kind and the work well done, satisfactory results are almost certain
to follow. Direct seeding is a much more rapid method than planting,
and where extensive areas are to be restocked within a short period
and seed is abundant, the work can be completed quickly. On the other
hand, this method is wasteful of seed because a large proportion
fails to germinate and the young seedlings often succumb to adverse
conditions, so that where seed is scarce or its cost high, planting
is the more practical method.
Because planting is the most reliable method it has been the one
most largely employed in extensive operations, both here and in
most European counties, but thorough tests are now being made of
direct seeding and under proper conditions it promises to be fairly
satisfactory. The Douglas fir region west of the Cascade Mountains
offers the most favorable conditions for direct seeding and except
on badly exposed south slopes, or where the growth of brush is
exceedingly dense, it is believed this method will prove a satisfactory
one for the timber owner to employ.
In the yellow pine regions conditions are not so satisfactory for
direct seeding, since this tree occurs largely in a region of deficient
rainfall. However, natural reproduction is abundant throughout
many portions of this type, and it is probable that direct seeding
will prove fairly successful if the proper methods are employed
and if forest conditions have not been too greatly disturbed. That
some method of successfully employing direct seeding with yellow
pine be found is greatly to be desired, since yellow pine seedlings
do not withstand transplanting well, but there is need for careful
experimentation before extensive seeding operations in this type
by private timber owners would be justifiable.
Western white pine, it is believed, will be easy to reproduce in
most of its native situations by direct seeding, though the greater
scarcity of its seed and the fact that it will be more subject to
destruction by birds and rodents because of its larger size may
make planting the more practical method.
Trees for planting can either be purchased from commercial nurserymen
or grown in nurseries established for that purpose near the planting
site. When only a few thousand trees are needed it is cheaper to
purchase them, but when extensive operations are contemplated,
covering hundreds of acres in which millions of trees will be needed,
it is far preferable for the owner to grow the trees in his own
nursery. Some initial outlay for the establishment of the nursery
will be necessary and a practical nurseryman should be employed,
but the saving in the cost of the trees will fully compensate for
these.
One, two and three year old trees, the latter once transplanted,
are usually employed in planting, the older trees being used for
the less favorable sites. In planting they are placed in rows
equidistant apart, the spacing varying from 4 to 12 feet, with a
general average of about 6 feet. The work may be done either in
the fall after growth has ceased or in the spring before growth
commences.
The cost of planting, of course, will vary greatly with the age of
the trees, the number planted per acre and the accessibility and
character of the planting site. With young trees and wide spacing,
the cost may be as low as $6.00 per acre, while in more unfavorable
situations where older plants are used and planting is more laborious
it may be as high as $16.00. A fair average, however, for those
areas which a timber owner would be most likely to plant up is
about $8.00 to $10.00 per acre.
In direct seeding, several different methods may be employed, such
as broadcasting over the entire area with or without previous
preparation of the soil, sowing in strips, or sowing in seed spots;
but observation and experiment have shown that it is necessary for
seed such as Douglas fir, yellow pine and western white pine to
come in close contact with the mineral soil in order that it may
germinate and the seedlings live; consequently only those methods
should be used which will accomplish this. Where the area has been
burned over previous to sowing and the mineral soil laid bare,
broadcast seeding may be employed. Where the ground will permit
the use of a harrow good results are obtainable by scarifying the
soil in strips about 10 feet apart and sowing the seed in these
strips. On unburned areas covered with a dense growth of fern,
salal, moss, grass, or other plants, this covering must be removed
by the seed spot method. This consists in removing the ground cover
with a grub hoe or mattock in spots of varying diameter (6 inches to
3 feet) and of various distances apart (6 to 15 feet), and sowing
the seed in these spots. The advantages of this method are that
a minimum amount of seed is used; the ground can be prepared and
the seed covered to whatever extent is desirable, and the soil
pressed down. This method is believed to be the one best suited
to the greatest variety of sites.
The amount of seed used per acre will, of course, vary with the
species and the method used, and the quality of the seed. The following
table indicates the approximate quantity of seed of good average
quality required per acre for three different methods, the average
cost when collected in fairly large quantities, and the number
of seed per pound:
No. pounds required per acre.
No. seed Cost per Broadcast, Seedspots
Species. per lb. pound. entire area. Strips. 6' apart.
Douglas fir 42,000 $1.50 2 - 3 1/2 - 1 1/2 - 3/4
Yellow pine 8,000 .50 10 - 12 2 - 2-1/2 1-1/2 - 2
Western white pine 14,000 .75 6 - 8 1-1/2 - 1-3/4 1 - 1-1/2
The total cost, too, will vary widely, not only because of the
different quantities of seed used but also because of the great extent
to which the methods are varied to suit the conditions occurring upon
the area. Simple broadcasting without any preparation or treatment
of the soil will not exceed 20 cents to 25 cents per acre for labor;
harrowing and sowing in strips, 85 cents to $1.10 per acre, and
sowing in seedspots, $2.00 to $5.00 per acre. Upon this basis the
total cost per acre will approximate the figures given in the table
below:
Broadcast over Seedspots,
Species. entire area. Strips. 6' apart.
Douglas fir $3.20-4.75 $1.00-2.60 $2.75-6.00
Yellow pine 5.20-6.25 1.85-2.35 2.75-6.00
Western white pine 4.70-6.25 2.00-2.40 2.75-6.00
RATE OF GROWTH AND PROBABLE RETURNS
Of all factors in calculating the financial possibilities of second
forest crops, the growth to be expected is the easiest to determine
with fair accuracy. Future stumpage value, tax burden and fire
risk are all subject to uncertain influences, but the approximate
yield of a given species under given natural conditions will be
the same in the future that it is now. To predict it requires only
study of existing stands without being misled by the influence
of conditions which will not be repeated.
On the other hand, an immense amount of misinformation is circulated
because of superficial observation. Enthusiasts discovering individual
trees which have made prodigious growth, or even fairly extensive
stands on fertile soil with heavy rainfall, will compute sawlog
yields at 40 or 50 years which are much too optimistic for general
application. Others, remembering some stand they have seen in
unfavorable localities, or noting shade-suppressed trees which
will not be paralleled after the virgin forest is removed, are
unduly discouraged. It is most essential that yield tables be made
by trained observers who know how to reach the true average, and
that the figures either actually come from the region to which they
are to be applied or are accompanied by a systematic analysis of
climatic and other conditions which permits intelligent comparison.
In calculating another yield on cut-over land, the system for an
even-aged new growth, such as will follow clean cutting of Douglas
fir, for example, is quite different from that necessary if the
cutting amounts only to selection of the merchantable trees and
leaves a fair stand of smaller ones. In the latter case, yield
tables based on average acreage production are of little use because
so much depends upon the character of the stand which remains on
the tract in question. Here the basis must be the rate of growth
of the average individual tree. An estimate by the number in each
present diameter class may be made of the trees which will escape
logging, showing, let us say for example, about five trees of each
diameter from 6 to 12 inches, or thirty-five in all which are over
6 inches. If the growth study indicates that in 20 years there will
have been added 6 inches in diameter we can estimate a crop of
five trees each of classes extending from 12 to 18 inches. Actually
the process will not be so simple, for the different aged trees
will not grow with equal rapidity, and several other factors must
be reckoned with, but the general principle is to apply rate of
growth knowledge to the material on hand, and study of this material
is essential.
For predicting even-aged crops resulting from entire restocking,
the acquisition of necessary basic information is as difficult, or
more so, but its application is far simpler. That the ground will
be fully stocked by natural or artificial means must be assumed,
but we can also assume that the result will be influenced only by
normal locality conditions and not by accidental condition of the
present forest. Therefore we use a yield table and not a growth
table. This can be made by actual measurement of existing second
growth stands of different ages, which proves not only the growth
rate but also the number of trees which the natural shade-thinning
process results in at different periods of the forest life. The
chief danger of inaccuracy in such information lies in basing it on
insufficient measurements or in applying it where soil or moisture
conditions are greatly different. The latter error can be guarded
against, however, by use of growth figures taken in conjunction
with it. For example, if a yield table showing 25,000 feet to the
acre at 50 years from seed is accompanied by one showing that the
average stand it represents is 125 high at 50 years and its average
50-year-tree is 14 inches in diameter, little investigation is
necessary to determine whether in any given locality the growth
falls far above or below that.
An attempt to reproduce here any considerable number of growth
and yield tables would be of doubtful use without more space than
is allowed to explain how they are made and used. There are many
technicalities, both mathematical and silvicultural, and unfortunately
most of the available figures for the Northwest, obtained by the
Forest Service, have not been generalized enough for wide popular
value. This is particularly true of yield tables which necessarily
require assuming standards of merchantability. While the best western
white pine table assumes that by the time a new crop is cut 7-inch
white pine will be salable, the best fir table was worked upon
a 12-inch diameter basis. Obviously this would show an unfairly
greater yield of a pine forest containing trees between 7 and 12
inches and be very misleading in calculating financial results at
the same age and stumpage rates; yet without the original data
there is no way of reducing both tables to the same basis. As an
example, however, to indicate how the financial possibilities of
second growth can be arrived at if a systematic study is made,
let us take the Douglas fir figures referred to.
DOUGLAS FIR
These are exceedingly reliable. Measurements were taken by the Forest
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PUBLIC-DOMAIN BOOK
Practical Forestry in the Pacific Northwest Protecting Existing Forests and Growing New Ones, from the Standpoint of the Public and That of the Lumberman, with an Outline of Technical Methods
primary
Full text in the local archive
Bibliographic record from the archive catalogue.