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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this unusually heavy stand, seedlings will begin to appear gradually
as individual old trees die and admit more and more light. The
other exceptions described are due to more recent ground fires
which have destroyed only the less hardy young growth and perhaps
also encouraged the lodge pole which, within its range, is always
quick to take burned ground.
The same result is almost sure to follow the "Indian" method of
forest protection sometimes advocated, which consists of purposely
running ground fires frequently in order to prevent accumulation
of sufficient debris to make an accidental fire fatal to timber of
commercial size. While such immunity may be secured, and perhaps
without sacrifice in stands so heavy as to have no reproduction
or when the latter has already been destroyed, it is obviously at
the expense of young growth if any exists. The counter argument
that a small proportion escaping will be sufficient for the second
crop is fallacious, because good timber will not be produced from
these scattering seedlings subjected to strong light by later logging.
Other means are necessary if the forest is to be reproduced.
This brings us to the possible management of yellow pine as an
even-aged forest. Thoughtful foresters are beginning to suspect
that while the "Indian" system of fire protection will usually
be fatal if ordinary logging practice is followed, it may serve
as an adjunct to a system which, if carefully applied, will be
better than selection cutting for some of our pine areas. This plan
is suggested where there is little young growth worth protecting
and consists of depending upon seed trees almost entirely for
reproduction, protecting carefully until the resultant even-aged
second growth is large enough to stand Blight fire, and then burning
periodically at such a season and with such safeguards as will
prevent the fire from being injuriously severe.
Not only are there many existing forests where absence of small trees
will permit clean cutting without sacrifice, but the same condition
is likely to occur eventually in stands following selective logging
if the second cut is long delayed. Although a good representation
of all ages under the diameter limit remains, the density of this
may become too great to allow further reproduction, and in time
the dominant trees will shade out all smaller growth. To allow this
purposely, choosing heavy cuts at intervals long enough to mature
the crop from seed rather than frequent light cuts of a constantly
replenishing stand, thus reducing the necessity of fire prevention,
is the aim of those who favor clean cutting as the most practicable
system. They assume that additional investment in seed trees, or
planting to insure prompt starting of a new crop after cutting,
will be unnecessary or at least offset by the smaller fire charge
and greater economy of logging.
Theoretically, such practice with a species adapted to the selective
method is uneconomical, for the ground is not fully utilized. Accidental
open places in the stand are not occupied by young trees which would
otherwise fill them. Time is lost by not starting the second crop
until after logging, for were there no fire previously there would
be considerable seedling growth which, although perhaps dormant
because of shade, would begin to amount to something much quicker than
that supplied by seed trees afterward. Nor is the system feasible
where there is much fir or other species less fire-resisting than
pine. It is dangerous in practice except where there is very little
combustible matter on the ground and fire is generally easy of
control, and exceedingly dangerous to advocate because serves as a
pretext and example for indiscriminate carelessness with fire under
all conditions. Finally, the alleged immunity of pine from injury by
ground fires is exaggerated. As a matter of fact, while the whole
stand is seldom perceptibly hurt, the immediate or gradual death of
a good tree here and there thins the stand very considerably in a
few years and it is such a thinning process in the past which makes
many pine tracts bear but 5,000 feet to the acre where otherwise
they would yield two or three times as much. Scorching also retards
the growth of trees not actually injured otherwise.
The technical objections given above may sometimes be offset by
practical advantages and the system is likely to receive expert
approval for certain conditions provided it is not used as a cloak
without taking sincere steps to replace the destroyed second growth
by adequate seed trees or artificial seeding. The latter danger may
easily warrant public alarm manifested by restrictive laws. Universal
ground burning of green timber will distinctly reduce the prospect
of unassisted natural reforestation on the great area of potential
timber land in which, as a resource, regardless of ownership, the
public is vitally interested. Under present conditions at least,
a large proportion of this is likely to be logged without any view
to a future crop. It is questionable whether any state should, or
will, legally approve ground burning except under stipulation of
proper management thereafter.
Unfortunately, it is necessary, in concluding this discussion of
yellow pine, to admit that while an attempt has been made to outline
the methods which will insure a second crop, the promise of satisfactory
financial return is more doubtful than that offered by some other
species. Compared with the typical coast trees, such as Douglas
fir, spruce and hemlock, the growth is slow and the yield small.
The chief circumstances in its favor are low land values, lesser
fire risk, cheapness and certainty of reproduction and excellent
market prospects. Less investment compensates somewhat for longer
rotation and smaller yield. Low taxation, however, is an absolute
essential.
WESTERN WHITE PINE (_P. Monlicola_)
Although as a distinct forest type this valuable tree is limited
chiefly to Idaho, it occurs occasionally in mixture or small tracts
over a wide range, and no reason appears why its commercial importance
should not be extended by planting on cut-over lands. Its high value,
rapid growth and heavy yield make it a particularly promising species
for growing under forestry principles. Its chief requirements for
success are fairly good moist land, access by the seed to mineral
soil and ample light for the young seedlings.
Except that it is more fastidious as to soil, white pine usually
demands about the same treatment as that prescribed for Douglas
fir, including clean cutting, slash burning and establishing a
new even-aged stand by seed trees or artificial restocking. Under
favorable conditions the stand is nearly even-aged, with little
undergrowth except of undesirable species. What small pine may
exist is seldom thrifty enough to be worth saving, so the best
thing is to clean off the ground for the double purpose of removing
weed trees and favoring valuable reproduction. Like that of fir,
the natural rotation of white pine forests seems to have been
accomplished often by the aid of fire, and where not given this aid
it suffers from lack of suitable seed-bed and from the competition
of other species already established.
Individual seed trees left in logging are not successful because
of shallow root system and almost certain windfall. Replacement
must be by seeding or planting, or by leaving small tracts of pine
surrounded by cleared fire lines to protect them when the slashing
is burned. The size and distance apart of these must be determined
by their situation and exposure to wind, considering both the danger
of windfall and the carrying of seed. Especially in younger growths,
the quantity of merchantable material tied up in this way is not
so great as is sometimes necessary in the case of red fir, where
single seed trees may contain several thousand board feet. On the
other hand, stumpage value may be high. For this reason artificial
replacement may often be more profitable, especially where there
is reasonable safety against recurring fire.
A thing to be borne in mind is that white pine seems to reach a
healthier and better development when mixed with a small proportion
of other species, such as cedar, tamarack, spruce, lodgepole pine
and Douglas fir, so there is no object in trying to produce an
absolutely pure stand. Some authorities think that 60 per cent
of pine, with the rest helping to prune it, is an ideal mixture.
LODGEPOLE PINE (_P. Murrayana_)
Present interest in private reproduction of this species hardly
warrants treating it at length in this publication, although
unquestionably it will eventually occupy a higher place in the
market than at present and its readiness to seize burned land in
many regions will make it a factor whether desired or not. Where
yellow pine will grow, the problem is most likely to be to discourage
lodgepole competition.
In strictly lodgepole territory, however, it may be the only promise
of a new forest. Generally speaking, an even-aged growth should
be induced by clean cutting if the entire crop can be utilized.
Slash burning in such cases is desirable. The chief difficulty
is in providing seed supply, for either individual seed trees or
small groups are almost certain to be blown down. Experiments so
far indicate that heavy strips must be spared, chosen to afford
the least present loss and safeguarded by fire lines.
In some lodgepole stands, especially where only certain sizes are
marketable, the cutting practically amounts to thinning. Here obviously
the effort should be to prevent over-thinning and to remove debris
with the least damage to the remaining stand. Piling and burning
is essential.
SUGAR PINE (_P. Lambertiana_)
This extremely valuable pine, commercially limited to the Oregon and
California mountains, is fastidious in its choice of conditions. Not
a frequent or prolific seed bearer, it still insists on a moist loose
seed-bed and prefers the natural forest floor to burned-over land. It
cannot stand drought when young and except on cool northern slopes
seedlings may be killed or stunted by exposure to full sunlight. On
the contrary it demands more and more light as it grows older and
will be suppressed or killed if unable to secure it. Under natural
conditions it perpetuates itself best by filling open places in
the forest.
For the above reasons, sugar pine is naturally a component of mixed
forests and it is doubtful whether it will be successfully grown as
a pure stand. Unfortunately, also, logging methods which are both
the simplest and most favorable to the reproduction of its associates
may be discouraging to sugar pine reproduction. Nevertheless, its
value warrants strong efforts to favor it and is an argument, where
considerable young sugar pine exists, against either clean cutting
or the use of fire.
The Forest Service, for which authority much of the above discussion
of this species was taken, offers the following general outline
for management in California:
"Since the forests in which sugar and yellow pine occur vary greatly
in composition, the method of treatment must also vary. For this
the forest types already distinguished may form a basis.
"On the lower portion of the sugar pine-yellow pine type, where
sugar pine forms but a small proportion of the stand, only the yellow
pine should be considered for the future forest. All merchantable
sugar pine may therefore be removed. It will be necessary to leave
only a few seed trees of yellow pine to restock the ground, although
usually it will be a wiser policy to leave a fair stand, since
this can be removed as a second cutting when reproduction is
established. This procedure would also hold for areas on which yellow
pine occurs in nearly pure stands. In these localities dense stands
of second-growth yellow pine occur. It will often be profitable,
where there is a market at hand, to thin these stands when they
are about 30 years old, removing the suppressed trees for mine
props. Trees 6, 8 and 10 inches and up are used for this purpose,
and sell for from 5 to 6 cents a running foot.
"On the upper portion of the sugar pine-yellow pine type, where
both species have about an equal representation in the stand, seed
trees of each should be left, wherever practicable, in the proportion
of two sugar pines to one yellow pine."
In the fir belt, where sugar pine and fir are the principal species,
the fir should be cut clean wherever possible and sugar pine should
be relied upon for the future forest.
"On all lands, the Douglas spruce, white fir and incense cedar
should be cut whenever possible, and chutes, skidways and bridges
should be constructed from the two last named species."
The following specific instructions are issued for marking timber
on National Forest sales in the sugar pine-yellow pine type:
"Owing to the large size of the trees, marking in this type of
forest should be done with special care, since a slight mistake
involves a comparatively large amount of timber.
"On nearly all of the lands included in this type the ground is
now but partly and insufficiently stocked with young timber, the
areas of forest are constantly becoming more accessible to markets,
and there is every indication of a strong future demand at greatly
increased prices. On nearly every tract, a second cut can be made
within thirty years. All marking under present sales should be
done strictly with reference to two points:
"1. Stocking the cut-over land as fully as possible with sugar and
yellow pine.
"2. Securing a second cut within thirty years.
"All cutting should be done under the 'selection system,' which
requires a careful choice of the individual trees to be removed.
Fixed diameter limits and the leaving of any specified number of
seed trees per acre can be very largely disregarded.
"The condition of every sugar and yellow pine on the sale area
should be studied closely to determine whether that tree will be
merchantable thirty years hence, by which time a second cut is
probable. As a rule the trees which will remain merchantable for
another thirty years should be left. Suppressed and crowded trees
which cannot develop should be removed. Under this system of marking,
ordinarily about one-half of the present stand of merchantable
pine would be left uncut. Will it pay?
"On areas where practically all of the pine is over-matured and
would be cut under the rule given above, a sufficient stand must be
left to reseed thoroughly the cut-over land. This requires not less
than four full seed-bearing trees, at least 25 inches in diameter,
per acre. The strongest and thriftiest trees available should be
selected for this purpose, but not less than the number specified
must be left even if every tree will be a total loss before a second
cut is possible.
"Extensive areas of pine timber which are not yet fully mature
should be excluded from the sale. On patches or small areas of
immature pine, which it is not practicable to exclude from the
sale, cutting should be very light, limited to one-third or less
of the largest trees, or omitted altogether.
"No attempt to discriminate sharply between sugar and yellow pine
should be made, as both trees are almost equally desirable. Where a
choice is necessary, sugar pine should be favored on moist situations,
as in canyons, moist pockets, or benches and on northerly exposures.
Yellow pine should be favored on dry situations, including exposed
ridges and southern exposures.
"Fir and incense cedar should be marked, as a rule, to as low a
diameter as these trees are merchantable in order to reduce the
proportion of these species in coming reproduction. It is essential,
however, that no large openings be made in the present stand since
the exposed ground is in danger of reverting to chaparral or of
becoming so dry from evaporation that no reproduction will follow
cutting. Where the stand of pine is insufficient to reseed thoroughly
and protect the cut-over area, enough sound, thrifty fir and cedar
should be left to form a fairly even cover with openings less than
a quarter of an acre in size.'"
The under current of all opinion upon sugar pine up to date is
that reproduction will not be very successful unless enough growth
to shelter the seedlings remains after logging. Where the fire
risk permits, the same end may be furthered by leaving the tops
scattered on the ground.
Little experimenting has been done in planting sugar pine, but
there are many indications that except where conditions strongly
favor natural reproduction it will be resorted to eventually if
any particular attempt is made to get this species. Leaving large
seed trees is not only expensive, but rather uncertain, because
heavy seed years are several years apart and squirrels consume a
large portion of an ordinary crop. Transplants which have received
nursery shelter until past the greatest danger of drying out should
prove most successful on heavily-cut south slopes.
REDWOOD (_Sequoia sempervirens_)
Although probably the most rapid-growing of all American commercial
trees and also of high market standing, redwood has been little
studied by foresters. The layman is still more confused by its many
peculiarities. Growing to a size of 20 feet in diameter and 350 feet
high, reaching an age of well over 1,000 years and seldom reproducing
by means of seed, it is not surprising that it was long regarded
as ill-adapted to second crop management. Although observing that
suckers sprout from the stumps with great rapidity, the lumberman
generally regarded these mushroom growths as abnormal and temporary,
and believed his virgin timber to be the finally-vanishing remnant
of a prehistoric species unsuited to present-day conditions.
It was next discovered that the suckering habit is no new one,
indeed that the majority of the present stand, however old, began
as sprouts from roots or stumps of its predecessors. This is evident
from the circular arrangement of several trees around the spot where
their parent stood. These old sprouts were of very slow growth,
for they were shaded by a forest of extreme density. As seedlings
they could have neither germinated nor grown, but as suckers they
were kept alive by the parent until light supply became available
through their increasing height or through thinning of the forest.
Under such conditions centuries were required to produce large
trees.
The owner of today, by cutting down the old stand, gives the suckers
conditions hitherto unknown to the redwood. The vigor and susceptibility
to the aid of light, which originally was necessary in the sprout
growth to perpetuate the species at all, now respond to entire
freedom and light in an astonishing manner. Even after severe slashing
fires char the stumps, the latter throw out clusters of sprouts
which grow several feet a year. Logging works 30 or 40 years old
have come up to trees nearly 100 feet high. Naturally such timber
has a heavy percentage of sapwood and is soft and brittle, but
it is already suitable for piling, box lumber and like purposes
and improves constantly.
Since reproduction by seed does not enter into the problem, financial
possibilities depend almost wholly on the nature of the original
stand. There are many types of redwood forest, pure and mixed,
flat and slope. If the old trees are few to the acre, the sprout
clusters will be so far apart that excess of side light will produce
clumps of swell-butted, short limby trees, of little use for lumber;
that is, unless there is also a seedling growth of fir or other
species to fill the blanks and bring up the density. Where such a
nurse growth is to be counted on, or where the redwood trees are
small and close together, ideal conditions for a certain, rapid
and well formed second crop exist.
The thinner the original redwood stand, the greater the effort
necessary at the time of logging to obtain the required density. The
leaving of seed trees of other species, with as many as possible small
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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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