Gloucester County Democrat. (Woodbury, N.J.) 1878-1932, 1905-01-12
HOW FORESTS GROW
THERE ARE TWO GREAT TYPES,
THE PURE AND MIXED.

W mere 4FeGS VI DtuCECht kAAbfeS
Enter the struggle For Existence.
The laws which govern the distribu
zion of trees produce the two great
types. the pure and the mixed forest.
The former is the result of local con
ditlons which trees of one kind only
can survive.
In the North woods the balsam oc-
cupes the swamps, usually to the eX-
clusioa of all competitors, since no
other of the native trees can thrive in
wet places In the Black Hills and
other parts of the middle west the
small demands of the bull pine upon
moisture enable it to form pure woods
on soil too dry to support other ma
tive trees. The jack pine of the New
Jersey barrens and the long leaf pine
of the southern states grow in pure
or nearly pure stands since they alone
can withstand the peculiar conditions
of these regions.
Where climate and soil are favorable
to various trees we find the mixed for
est, the number of species in mixture
depending upon the suitability of the
locality to forest growth.
Upon the hardwood fats of the Adj
rondacks the hard maple, the yellow
birch and the beech are the only de
ciduous trees able to withstand the Sc
we're climate. In the southern Appa-
lachian forests, where the trees of the
north and south meet under conditions
100 different kinds.
The distribution of trees, therefore,
is the joint result of local conditions
and Of the individual and varying re-
quirements of the different species up
ON moisture, soil and climate. The
laws, however, which govern forest dis
tribution are not identical with those
which regulate the behavior of trees
in mixture. They do not explain why
each species, if undisturbed. maintains
the same proportion in the mixed for
est. Why does not the hard maple
drive out its competitors in the Adiron-
dacks, the oak gain the upper hand in
the forests of the southern Appala-
chians, the red fir exterminate the
western hemlock on the Pacific slope?
Wherever a mixed forest occurs
there is an unrelenting struggle going
on. Let us see how the combatants
are armed and why the representation
of each species remains unchanged.
The more important of the character
istics which affect the capacity of a
tree to hold its own in mixture with
trees of other kinds are its demands
upon light, its rate of growth and its
power of reproduction. No two species
require an equal amount of light, grow
at the same rate or are Identical in
their capacity TO reproduce themselves.
The endowment of each, with habits
differing from those of its neighbors,
but with strength and weakness so
balanced that all which occur in mix
ture enter the struggle for existence
upon an equal footing, is one of the
marvellous feats of nature.
The red spruce of the North woods,
through its ability to endure dense
shade, has been given the power to
hold its own against faster growing
competitors. some of which exceed it
greatly in their capacity to reproduce
themselves. The young spruces which
spring up here and there throughout
the forest struggle along under the
heavy crowns of the hard woods, where
q tree making more insistent demands
upon light could not survive.
In the forests of the southern APP
palachians the oak is in many localities
the characteristic tree Growing rap
idly and exceedingly hardy, it might be
expected to increase steadily its pro-
portion in the mixture. The equilibri-
UNI is maintained through the fact that
the oak can endure but little shade
and that its seed is heavy, limiting its
reproduction to the immediate vicinity
of the parent tree.
In the same region the yellow poplar
and the chestnut, both trees which
grow rapidly and are capable of endur
ing considerable shade, are controlled,
the one because much of its seed is
barren, the other because many of the
red cedar, of slow growth and sparse
representation, is aided through the
distribution of its seeds by birds, with
their power to terminate unimpaired.
The aspen, short lived and requiring
much light, holds its own with longer
lived and shade enduring trees because
its downy seed is produced in great
quantities and IS scattered far and
wide by the wind. The ash and the
Eastwood, of rapid growth and bearing
an abundance of seed. are withheld by
strong demands upon light and by the
seed of fresh and fertile soil. The
red fir, equaled by few North American
trees in rapidity of growth and other
wise well equipped to gain the upper
hand in its region, is controlled through
the usual failure of its seed to germi-
nate except when accident has remov
ed the leaf litter and exposed the min