THE DISTRIBUTION AND COMPOSITION OF THE NORTH AMERICAN FORESTS.
The forests of the United States, Map, Fig. 44, may be conveniently
divided into two great regions, the Eastern or Atlantic Forest,
and the Western or Pacific Forest. These are separated by the great
treeless plains which are west of the Mississippi River, and east of
the Rocky Mountains, and which extend from North Dakota to western
Texas.[1]
[Illustration: Fig. 44. Forest Regions of the United States. _U. S.
Forest Service._]
The Eastern Forest once consisted of an almost unbroken mass, lying in
three quite distinct regions, (1) the northern belt of conifers, (2)
the southern belt of conifers, and (3) the great deciduous (hardwood)
forest lying between these two.
(1) The northern belt of conifers or "North Woods" extended
thru northern New England and New York and ran south along the
Appalachians. It reappeared again in northern Michigan, Wisconsin and
Minnesota. White pine, Fig. 45, was the characteristic tree in the
eastern part of this belt, tho spruce was common, Fig. 56, p. 213,
and white and Norway pine and hemlock distinguished it in the western
part. Altho the more valuable timber, especially the pine, has been
cut out, it still remains a largely unbroken forest mainly of spruce,
second growth pine, hemlock and some hardwood.
[Illustration: Fig. 45. Interior of Dense White Pine Forest, Cass
Lake, Minn. _U. S. Forest Service._]
(2) The southern pine forest formerly extended from the Potomac River
in a belt from one to two hundred miles wide along the Atlantic coast,
across the Florida peninsula, and along the gulf of Mexico, skipping
the Mississippi River and reappearing in a great forest in Louisiana
and Eastern Texas. It was composed of almost pure stands of pine, the
long-leaf, Fig. 46, the short-leaf, and the loblolly, with cypress
in the swamps and bottom lands. In southern Florida the forest is
tropical, Fig. 47, like that of the West Indies, and in southern Texas
it partakes of the character of the Mexican forest.
[Illustration: Fig. 46. Long-leaf Pine Forest. Oscilla, Georgia. _U.
S. Forest Service._]
[Illustration: Fig. 47. Semi-tropical Forest, Florida. Live Oak,
Surrounded by Cabbage Palmetto, and Hung With Spanish Moss. _U. S.
Forest Service._]
(3) Between these north and south coniferous belts, lay the great
broad-leaf or hardwood forest, Fig. 48, which constituted the greater
part of the Eastern Forest and characterized it. It was divided into
two parts by an irregular northeast and southwest line, running from
southern New England to Missouri. The southeast portion consisted
of hardwoods intermixed with conifers. The higher ridges of the
Appalachian Range, really a leg of the northern forest, were occupied
by conifers, mainly spruce, white pine, and hemlock. The northwest
portion of the region, particularly Ohio, Indiana, and Illinois, was
without the conifers. It was essentially a mixed forest, largely oak,
with a variable mixture of maples, beech, chestnut, yellow poplar,
hickory, sycamore, elm, and ash, with birch appearing toward the north
and pine toward the south.
[Illustration: Fig. 48. Broad-leaf Forest, Protected from Cattle and
Fire. Hancock Co., Indiana. _U. S. Forest Service._]
Taking the Eastern Forest as a whole, its most distinguishing feature
was the prevalence of broad-leaved trees, so that it might properly be
called a deciduous forest. The greatest diversity of trees was to be
found in Kentucky, Tennessee and North Carolina, and this region is
still the source of the best hardwood lumber.
This great eastern forest, which once extended uninterruptedly from
the Atlantic to the Mississippi and beyond, has now been largely
lumbered off, particularly thru the middle or hardwood portion, making
way for farms and towns. The north and south coniferous belts are
still mainly unbroken, and are sparsely settled, but the big timber
is cut out, giving place to poorer trees. This is particularly true of
the white pine, "the king of American trees," only a little of which,
in valuable sizes, is left in Michigan, Wisconsin and Minnesota. In
the same way in the south, the long-leaf pine, once the characteristic
tree, is fast being lumbered out.
[Illustration: Fig. 49. Irrigated Ranch on Treeless Alkali Plain. Rio
Blanco Co., Colorada. _U. S. Forest Service._]
The Western or Pacific forest extends two great legs, one down the
Rocky Mountain Range, and the other along the Pacific coast. Between
them lies the great treeless alkali plain centering around Nevada,
Fig. 49. In these two regions coniferous trees have almost a monopoly.
Broad-leaved trees are to be found there, along the river beds and in
ravines, but they are of comparatively little importance. The forest
is essentially an evergreen forest. Another marked feature of this
western forest, except in the Puget Sound region, is that the trees,
in many cases, stand far apart, their crowns not even touching, so
that the sun beats down and dries up the forest floor, Fig. 50.
There is no dense "forest cover" or canopy as in the Eastern Forest.
Moreover these western forests are largely broken up, covering but a
part of the mountains, many of which are snow-clad, and interrupted
by bare plains. Along the creeks there grow a variety of hardwoods. It
was never a continuous forest as was the Eastern Forest. The openness
of this forest on the Rockies and on the eastern slopes of the Sierra
Nevadas is in marked contrast to the western slopes of the Sierras,
where there are to be seen the densest and most remarkable woods of
the world, Fig. 51. This is due to the peculiar distribution of the
rainfall of the region. The precipitation of the moisture upon the
northwest coast where the trees are dripping with fog a large part of
the time, is unequaled by that of any other locality on the continent.
But the interior of this region, which is shut off by the high
Sierra Nevadas from the western winds, has a very light and irregular
rainfall. Where the rainfall is heavy, the forests are dense; and
where the rainfall is light, the trees are sparse.
[Illustration: Fig. 50. Open Western Forest, Bull Pine. Flagstaff,
Arizona. _U. S. Forest Service._]
Along the Rockies the characteristic trees are Engelmann's spruce,
bull pine, Douglas fir, and lodgepole pine. As one goes west, the
variety of trees increases and becomes, so far as conifers are
concerned, far greater than in the east. Of 109 conifers in the United
States, 80 belong to the western forests and 28 to the eastern. The
Pacific forest is rich in the possession of half a dozen leading
species--Douglas fir, western hemlock, sugar pine, bull pine, cedar
and redwood.
[Illustration: Fig. 51. Dense Forest of Puget Sound Region, Red Fir
and Red Cedar. Pierce Co., Washington. _U. S. Forest Service._]
But the far western conifers are remarkable, not only for their
variety, but still more for the density of their growth, already
mentioned, and for their great size, Fig. 52. The pines, spruces and
hemlocks of the Puget Sound region make eastern trees look small, and
both the red fir and the redwood often grow to be over 250 feet high,
and yield 100,000 feet, B.M., to the acre as against 10,000 feet,
B.M., of good spruce in Maine. The redwood, Fig. 53, occupies a belt
some twenty miles wide along the coast from southern Oregon to a point
not far north of San Francisco and grows even taller than the famous
big trees. The big trees are the largest known trees in diameter,
occasionally reaching in that measurement 35 feet.
[Illustration: Fig. 52. Virgin Forest of Red Fir, Red Cedar, Western
Hemlock, and Oregon Maple. Ashford, Washington. _U. S. Forest
Service._]
[Illustration: Fig. 53. Redwood Forest. Santa Cruz Co., Calif. _U. S.
Forest Service._]
The big tree, Fig. 54, occurs exclusively in groves, which, however,
are not pure, but are scattered among a much larger number of trees of
other kinds.
[Illustration: Fig. 54. Big Tree Forest. Sierra National Forest,
California. _U. S. Forest Service._]
The great and unsurpassed Puget Sound forest is destined to be before
long the center of the lumber trade of this country.
These two great forests of the east and the west both run northward
into British America, and are there united in a broad belt of
subarctic forest which extends across the continent. At the far north
it is characterized by the white spruce and aspen. The forest is open,
stunted, and of no economic value.
Taking all the genera and species together, there is a far greater
variety in the eastern than in the western forests. A considerable
number of genera, perhaps a third of the total, grow within both
regions, but the species having continental range are few. They
are the following: Larch (_Larix laricina_), white spruce (_Picea
canadensis_), dwarf juniper (_Juniperus communis_), black willow
(_Salix nigra_), almond leaf willow (_Salix amygdaloides_), long leaf
willow (_Salix fluviatilis_), aspen (_Populus tremuloides_), balm of
Gilead (_Populus balsamifera_), and hackberry (_Celtis occidentalis_).
[Footnote 1: ORIGINAL FOREST REGIONS OF THE UNITED STATES.
Area Area
Thousand acres Per cent.
Northern forest 158,938 8.4
Hardwood forest 328,183 17.3
Southern forest 249,669 13.1
Rocky Mountains forest 155,014 8.1
Pacific forest 121,356 6.4
Treeless area 887,787 46.7
--------- -----
Total land area 1,900,947 100.0
]
THE DISTRIBUTION AND COMPOSITION OF NORTH AMERICAN FORESTS.
REFERENCES:[A]
Sargent, _Forest Trees_, Intro., pp. 3-10.
Bruncken, pp. 5-16.
Roth, _First Book_, pp. 209-212.
Shaler, I, pp. 489-498.
Fernow, _For. Inves._, pp. 45-51.
Fernow, _Economics_, pp. 331-368.
[Footnote A: For general bibliography, see p. 4.]