Three extensive mountain systems, running north and south, give rise to
at least eight topographic subdivisions of the country, going from east
to west.
1. The narrow belt of level coast and hill country along the Atlantic
shore, from 100 to 200 miles in width with elevations up to 1,000 feet,
but especially low along the seacoast from Virginia south; drained by
short rivers navigable only for short distances from the mouth; a
farming country, with the soils varying from the richest to the poorest;
some 300,000 square miles.
2. The Appalachian mountain country, nearly of the same width as the
first section, with elevations up to 5,000 feet; the watershed of all
the rivers to the Atlantic, of several rivers to the Gulf, and of the
eastern affluents of the Mississippi; a mountain country, of about
360,000 square miles extent, rich in coal, iron and other minerals,
except in its northern extension formed of archean rock.
3. The great river basin of the Mississippi, a Central plain of glacial
and river deposit, rising gradually from the Gulf to the headwaters for
more than 1200 miles, and nowhere over 1,000 feet above sea level; the
richest agricultural section, 700,000 square miles, more or less, in
extent.
4. The plateau, rising towards the Rocky Mountains from 1,000 to 5,000
feet above sea level, some 870,000 square miles in extent, a region of
scanty rainfall, hence of prairie and plain, but mostly rich soil of
undetermined depth, capable of prolific production where sufficient
water supply is available.
5. The Rocky Mountain region, rising from 5,000 to near 10,000 feet
(except some higher peaks), an arid to semi-arid district of rugged
ranges, covered mostly with forest growth, often open and of inferior
kind, with tillable soils in the narrow valleys, requiring irrigation
for farm use; a mining country, rich in gold and silver, extending over
150,000 square miles.
6. The Sierra Nevada Mountain Range, including the Coast Range, rarely
over 7,000 feet elevation, arid to semi-arid on the Eastern slopes;
humid, and supporting magnificent forest growth on the Western slopes;
some 190,000 square miles.
7. The Interior Basin, lying between the two preceding mountain ranges,
some 400,000 square miles; for the most part a desert, although in parts
supporting a stunted growth of pinon and juniper, and, where irrigation
is possible, productive.
8. The interior valleys of the Sierra, comprising about 30,000 square
miles, which, under irrigation, have become the garden spots of the
Pacific.
To these topographic subdivisions correspond in part the climatic and
the forest conditions, although variation of soil, and of northern and
southern climate produce further differentiation in types, and in
distribution of field and forest.
The first three sections were originally densely wooded--the great
Atlantic forest region--but farms now occupy most of the arable
portions; the fourth and seventh are forestless, if not treeless, while
the fifth and sixth were more or less forested--the Pacific Coast
region.
Floristically also, these topographic conditions are reflected, namely
in the wide, north and south distribution of species, unimpeded by
intervening mountain ranges, and in the change in composition from east
to west. The two grand floristic divisions of the Atlantic and the
Pacific forest, having but few species in common, are separated by the
plains and prairies. The Atlantic forest is in the main composed of
broadleaf trees with conifers intermixed, which latter only under the
influence of soil conditions form pure stands, as in the extensive
pineries of the South and North, and in the northern swamps and on
southern mountain tops. The central region west of the Alleghanies
exhibits little conifer growth in its composition, and is most widely
turned to farm use. White Pine, hemlock and spruce are the important
coniferous staples of the northern section, and a number of Yellow Pine
species, with Bald Cypress and Red Cedar, are the valuable conifer
species in the South. As regards valuable hardwoods, there is but little
change from north to south.
The Pacific forest flora is almost entirely coniferous, but here also
climatic conditions permit a distinction of two very different forest
regions, the Rocky Mountain forest being mostly of rather inferior
development, and the Sierra forest exhibiting the most magnificent tree
growth in the world.
Nearly half the country is forestless, grassy prairie and plain, some
400 million acres being of the latter description, while open prairie
and brush forest, or waste land occupies 600 million acres.
Within the forest region of the East some 250 million acres have been
turned into farms, leaving still two-thirds of the area either under
woods, or else wasted by fire. Although any reliable data regarding this
acreage are wanting, the area of really productive woodland in this
section may probably be set down as not exceeding 300 million acres,
which would be nearly 40% of the total area, varying from 13% in the
Central agricultural States to 50% in the Southern States; Maine, New
Hampshire and Arkansas being most densely wooded, with over 60%. The
Rocky Mountain and Sierra forests, each with 100 million acres, would
bring the total productive woodland area to a round 500 million acres,
or about 26% of the whole. (Later estimates including brushlands of
doubtful productive capacity, increase this area to 550 million acres.)
It is almost idle to attempt an estimate of the timber still standing
ready for the axe; not only are the data for such an estimate too
scanty, but standards of what is considered merchantable change
continuously and vitiate the value of such estimates. The writer’s own
estimate, made some years ago, of 2,500 billion feet, which by others
has been treated as authoritative and forming a basis for predicting the
time of a timber famine, and which was lately sustained by an extensive
official inquiry, must nevertheless be considered only as a reasonable
guess, ventured for the purpose of accentuating the need of more
conservative treatment of these exhaustible supplies, in comparison with
the consumption which represents around 45 billion feet B.M., and
altogether 23 billion cubic feet of forest-grown material, the ultimate
value of all forest products reaching the stupendous sum of around 1,250
million dollars. And, as in other countries, this lavish consumption of
forest growth, from five to fifteen times that of Europeans, has shown
in the past a per capita increase of 30 per cent. for every decade.
The bulk of the standing timber is to be found along the Pacific Coast,
in the Sierra, and in the Southern States with their extensive pineries;
the Northern and Eastern sections are within measurable time of the end
of their virgin supplies of saw timber. The practice of culling the most
valuable species has changed the composition in the regeneration, making
it inferior, and large areas have been rendered worthless by fires.
The loss by fire, the bane of American forests, as far as loss in
material is concerned probably does not exceed 2 or 3 per cent. of the
consumption, and may be valued at say 25 million dollars per annum. But
the indirect damage to forest and soil, changing the composition, baring
the soil, and exposing it to erosion and washing, turning fertile lands
into wastes, and brooks and rivers into torrents, is incalculable.
There is no doubt that at the present rate of consumption the bulk of
the virgin supplies will be used up in a measurable time, which will
force a reduction in the use of wood materials; a more or less severe
timber famine is bound to appear,--indeed, has begun to make its
appearance; and all recuperative measures will not suffice to stave it
off, although they may shorten the time of its duration.