The midland journal. (Rising Sun, Md.) 1885-1947, 1904-12-09
gov THE FOREST GROWS.
THE LAWS WHICH GOVERN THE
DISTRIBUTION OF TREES.

Be PleaSanter For Some Insight
Gained Into What is Going on
Therein. y
The laws which govern the distribu-
tion of trees produce the two great
types, the pure and the mixed forest. /
The former is the result of local con-
ditions which trees OF one kind only
can survive.
In the North Woods the balsam Oc-
cupies the swamps, usually to the ex-
clusion 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 favor
able to various trees. we find the
mixed forest, the number OF species in
mixture depending upon the suitability
of the locality to forest growth.
Upon the hardwood flats of the
Adirondacks the hard maple, the yell
low birch and the beech are the only
deciduous trees able to withstand the
severe climate. In the southern Ap-
palachian forests, where the trees of
the North and South meet under con-
ditions favorable to both, we find
more than one hundred 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
distribution 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 forest. Why does not the hard
maple drive out its competitors in the
Adirondacks, the oak gain the upper
hand in the forests of the southern
Appalachians, 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 charac-
teristics which affect the capacity of
tree to hold its own in mixture with
trees of other Kinds are its demands
upon light, it's 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 repro
duce themselves. The endowment OF
each, with habits differing from those
of it's neighbors, but with strength and
weakness so balanced that all which
occur in mixture enter the struggle
for existence upon an equal footing,
is one of the marvellous feats of ma
ture.
The red spruce of the North Woods
through it's ability to endure dense
shade, has been given the power to
hold it's own against faster growing
competitors, some Of which exceed 1t
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 hardwoods, where
a tree making more insistent demands
upon light could not survive.
In the forests of the southern Appa-
lachians the oak is, in many localities,
the Characteristic tree. Growing rar-
idly and exceedingly hardy, it might
be expected to increase steadily its
proportion in the mixture. The equili-
brium is maintained through the fact
that the oak can endure but little
shade, and that its seed is heavy, linn
iting its reproduction to the immediate
vicinity of the parent tree.
In the same region. the yellow pop
lar and the chestnut, both trees which
grow rapidly and are capable OF en-
during considerable shade, are con-
trolled, the one because much of its
seed is barren, the other because
many of the nuts are eaten by animals.
And the red cedar, of slow growth and
sparse representation, is aided
through the distribution of its seeds
by birds, with their power to germi-
nate unimpaired.
The aspen, short-lived and requir-
ing 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 need of fresh and
fertile soil. The red fir, equaled by
few North American trees in rapidly