1902 Encyclopedia > United States > Vegetation

United States
(Part 20)


Part 20. Vegetation

No portion of the United States attains so high a latitude that the forest growth should be necessarily dwarfed by the cold, or disappear altogether. The northern boundary is, however, practically nearly the limit beyond which valuable timber cannot be expected. The portions of the United States where altitude is fatal to the growth of forest vegetation are insignificant as compared with the area of the whole country. The Appalachian ranges—which originally were densely forested from extreme north-east to extreme south-west, and which still continue to be so over a considerable portion of their extent—only rise at a very few points high enough to cause the forests to disappear. This is the case particularly with Mount Washington and the higher adjacent peaks, and with the summits of the most elevated part of the system in North Carolina. The Adirondacks are densely wooded, even almost to the highest summits. In the most elevated mountain-chains making up the Cordilleran system, want of moisture appears to co-operate with elevation in thinning out the forests on their flanks and causing them to disappear entirely on the highest ranges. The timber line on the most elevated peaks of Colorado reaches from 11,000 to about 11,500 feet,—the summits themselves rising from 2000 to 3000 feet higher. The Sierra Nevada is bare of forests in its highest portions. The high region about Mount Whitney is, where not snow-covered, nothing but an entirely bare mass of granite domes and needles. In the central part of the Sierra, in the vicinity of the Yosemite valley, forest vegetation is extremely scanty above 9000 feet, and the upper 3000 feet of the highest peaks is entirely bare of trees. If large areas of the United States are destitute of trees, and other regions but very poorly supplied, the chief cause of this is want of sufficient moisture.

In briefly indicating the nature and distribution of the forests of the United States, we may begin with the Appalachian region, which here must be taken as embracing also the country to the west and south-west, including the valleys of the Mississippi and Missouri, as far west as the western boundary of the State of Missouri, or about the 95th meridian, to the east of which lies, coincident with the region of generally abundant and every-where sufficient rainfall, that portion of the United States which is almost everywhere densely forested, and the only portion which is so, with the exception of a comparatively narrow strip on the Pacific coast. Included within this densely-forested region of the Appalachian system and Mississippi valley there is quite a large area destitute of continuous forests,—the so-called " prairie region " (see below). The portion of the United States first settled by Europeans was, almost without exception, a densely-forested region, over which the aboriginal inhabitants roamed, without having interfered to any perceptible extent with the natural forest growth of the country. Their numbers were small, and their habitations were, almost without exception, either on or near the shores of the ocean and its bays and indentations, or along the river bottoms, in such places as were naturally grassed and not forested. This densely-forested region extends throughout the wdiole length of the Atlantic coast from Maine to Florida, west through the region of the Great Lakes to beyond Lake Superior, and to the south-west through Louisiana and for some distance into Texas. It differs from the densely-forested region of the Pacific in that it is essentially a region of deciduous or hardwood forests, while the latter is essentially one of coniferous trees ; it differs from the forested region of the Rocky Mountains in that the latter is not only essentially a region of coniferous trees, but one where the forests do not by any means occupy all the area, neither do they approach in density or economic importance those of the eastern division of the country. Again, the forests of the east embrace a great variety of species, which, as a rule, are very much intermingled, and do not, unless quite exceptionally, occupy areas chiefly devoted to one species; while, on the other hand, the forests of the west— including both Rocky Mountain and Pacific coast divisions— exhibit a small number of species, considering the vast area embraced in the region; and these species are, in quite a number of instances, extraordinarily limited in their range, although there are cases in which one or two species have almost exclusive possession of very extensive regions. The eastern forested region, while continuous from north-east to south, south-west, and west, is of course marked by changes in the species corresponding with the changes in temperature between the extreme north-east and the extreme south. These changes, however, are almost without exception gradually made, and we pass almost imperceptibly from a northern to a southern forest. This condition is, in a measure, the consequence of the breadth and high elevation of the Appalachian system in its southern extension, along which elevated belt the northern aspect of the arboreal vegetation is prolonged into a. region almost semi-tropical.

The following hardwood trees may be mentioned as being the most prominent and important in the forests of the eastern division of the country. The sugar-maple (Acer saecharinum), called also the hard and rock maple, ranges as far south as northern Alabama, but is of the most economical importance in New England and the region of the Great Lakes. On the southern shore of Lake Superior, in the higher portions of the country, on and near the divide between the waters flowing into the lake and those which descend to the Mississippi, the forest, over large areas, is almost exclusively made up of this species, the "bird's-eye" variety—formerly much prized for cabinet work—being there abundant. The other species of maple of less importance are the soft maple (A. dasycarpum), having a wide range, and attaining its greatest development in the valley of the lower Ohio, and the red maple (A. rubrum), also ranging from New Brunswick westward to the Lake of the Woods and south to Texas, and being largest and most abundant in the central portion of the Mississippi valley. The oaks range over the entire eastern forested region from Maine to Florida, and west nearly as far as arboreal vegetation extends. The number of species is large. The white oak (Q. alba) ranges over nearly the whole forest region of the east, reaching its greatest development along the western portion of the Appalachian belt, and in the valley of the Ohio and its tributaries. The burr oak (Q. macrocarpa) has almost as wide a range as the white oak, extending farther west and north-west than any oak of the Atlantic forests ; it forms, with the scarlet oak (Q. coccínea), the principal growth of the "oak-openings" in the prairie region. The red oak (Q. rubra) has also a wide range; it extends farther to the north than any other species. The jack oak or black jack (Q. nigra) is a small tree of little value except for fuel, but widely disseminated in the west and south-west of the eastern forest region, and forming with the post oak (Q. obtusiloba) the growth of the so-called "cross timbers" of Texas. The live oak (Q. virens) is an evergreen tree of considerable value, chiefly developed along the Gulf coast and through western Texas into the mountains of northern Mexico. The chestnut oak (Q. Prinus) ranges through the Appalachian region, from Lake Champlain to northern Alabama, and west to central Kentucky and Tennessee. Its bark is used in preference to that of the other North American oaks in tanning. The ash is represented by several species. The white ash (Fraxinus Americana) is of special value, and its range is very extensive, namely, east and west from Nova Scotia to Minnesota, and south-west to the extreme border of Texas. This species has its greatest development in the bottom lands of the lower Ohio valley. Towards the west and south-west it diminishes in size and importance, and is replaced to a considerable extent by the green ash (F. viridis). The range of the red ash (F. pubescens) is nearly as large as that of the white ash, except that it does not extend quite so far to the south-west. Its wood is less valuable. The chestnut (Castanea vesca, var. Americana) is an important tree, with a wide range. From southern Maine west to Indiana, and south along the Appalachians to northern Alabama, attaining its greatest development along the flanks of the mountains in North Carolina. The birch is represented in the eastern forest region by several species. The white, canoe, or paper birch (Betula papypracea) reaches a higher latitude than any other tree of the American deciduous forest. It ranges south to the mountainous region of northern Pennsylvania, and west to British Columbia. The yellow or grey birch (B. lutea) is one of the largest and most valuable trees of the New England forest, ranging south along the higher portion of the Appalachians to North Carolina, and west to southern Minnesota. There are in the region several species belonging to the two genera of the Juglandaceae, Juglans and Carya, which have a wide range, and are of importance both for their wood and for their fruit, and which also are among the most attractive ornaments of the forest. Prominent among these are the hickory (Carya alba), the butternut (Juglans cinerea), the black walnut (J. nigra), and the pecan (C. olivaeformis). The pecan does not occur to the north-west of Indiana, has its greatest development in the rich bottom lands of Arkansas, and is the largest and most important tree of western Texas. The butternut occurs in New England, but is by no means an abundant tree in that region; farther west, especially in the valley of the Ohio, it attains its maximum development. The black walnut is hardly known in New England, unless on its extreme western border; but south-westward along the Appalachians and west to the Mississippi it is a tree of great value and importance. It attains its maximum development on the western slope of the southern portion of the Appalachian range and thence to Arkansas. Hardly any other wood is ever used for gunstocks. The American elm (U. Americana) has a wide range, extending from southern Newfoundland to Texas and west to central Nebraska. This species is especially the tree of the river bottoms, and specimens occurring isolated in natural meadows often attain great size. The rock or white elm (U. racemsa) is a tree hardly occurring in New England, but largely developed in the region of the Great Lakes, west to north-eastern Iowa, and south to central Kentucky. Its wood is considerably denser than that of U. Americana. The beech (Fagus ferruginea) occurs through nearly the whole of the eastern forest region, ranging from Nova Scotia south and south-west to Florida and Texas, and west of Missouri. The linden, lime, basswood, or white-wood (Tilia Americana) is a tree of wide range, occurring more and more abundantly as we go west from New England through the region south of the Great Lakes into the Ohio valley, and found sound along the Appalachians to Georgia. It has its maximum development towards the west and south-west in the rich bottom-lands. The tulip tree (Liriodendron tulipifera), called also yellow poplar and white-wood, is one of the largest and most beautiful trees of the eastern forest region. It is rare in New England, but has its maximum development from New Jersey south along the slopes of the Appalachians to Tennessee and North Carolina, and west in the Ohio valley. The genus Magnolia is represented by several species, two of which are of importance, especially for the great beauty of the tree and its flowers. These – M. glauca and M. grandiflora- like the other species of the magnolia, are pretty closely limited to the Atlantic coast and Gulf region, and the lower portion of the Mississippi valley. M. glauca, which has a variety of names, among which those of sweet bay and white laurel are most common, is found over a small area on Cape Ann in Massachusetts, and in no other place in New England, - its range being from New Jersey southward, chiefly along the coast to Florida, and west to Arkansas and Texas. M. grandiflora, called the big laurel or the bull bay, an evergreen, and one of the finest trees of the region, is pretty closely limited to the southern and south-western coast, ranging from North Carolina south to Tampa Bay, westward to south-western Arkansas, and along the Texas coast to the valley of the Brazos. There are two trees known familiarly as the locust are of considerable importance. One is the Robinia Pseudacacia, commonly called either simply the locust or the yellow locust’; the other is Gleditschia triacanthos, to which the popular names honey locust, acacia, sweet locust, and black locust are given. The former occurs naturally in the Appalachians from Pennsylvania to Georgia, reaching its maximum development on the western slopes of the mountains of West Virginia, but has been introduced and cultivated over the whole region east of the Rocky Mountains, wherever trees can be made of grow. This tree, however, over an extensive portion of the region where it was formerly cultivated has been exterminated by the attacks of the "locust borer" (Cyllene picta). The other locust, the three-thorned acacia, ranges from Pennsylvania, along the western flanks of the Appalachians, south as far as Florida, south-west through northern Alabama and Mississippi to Texas, and west from Pennsylvania through southern Michigan to eastern Kansas. It is the characteristic tree of the "barrens" of middle Kentucky and Tennessee, attains its maximum development in the lower Ohio bottom-lands. It is widely cultivated throughout the region east of the Appalachians for shade and ornament, and for hedges. There are certain trees and shrubs in the eastern forest region of little or no economical importance, but which especially when in flower, are highly ornamental. Of these only a few can be mentioned: the mountain ash (Pyrus Americana), ranging over nearly the whole region, and much cultivated as an ornamental tree on account of the beauty of its fruit, of dark reddish or scarlet color, and remaining long upon the branches; the sumach (Rhus glabra), a handsome shrub, from 4 to 10 feet in height and very striking both for foliage and fruit, and a very characteristic feature of the New England landscape, as seen along the borders of the forests and by the sides of country roads; the mountain laurel (Kalmia latifolia), covering extensive areas of half-cleared forests in the hilly regions and very conspicuous at the flowering season, June and July, one of the most beautiful of all the characteristic native America shrubs; the dog-wood or cornel (Cornus alternifolia), a beautiful shrub, rising occasionally to sufficient height to be called a tree, ranging from the St Lawrence to Alabama, and in certain regions, especially in parts of New Jersey and Pennsylvania, very conspicuous at the time of its flowering , the landscape from a distance looking as if it had been snowed upon. The red-bud (Cercis canadnesis), a small tree, is a conspicuous feature of the forest in the extreme south-west, especially in southern Arkansas, the Indian Territory, and eastern Texas.

Although the forest vegetation of the eastern region is essentially deciduous character, coniferous trees are widely spread over the whole country from Maine to the southern border of Georgia. The genus Pinus is by far the most widely distributed and most interesting of the conifers. First in value is the while pine (P. Strobus), a northern tree, having its maximum development in the region of the Great Lakes, ranging from Maine west to Lake Superior, and south-west along the Appalachians to Georgia, and attaining a height greater than that of any other species in the eastern forest region, namely, somewhat less than half that of the tallest trees in the Pacific coast belt. The most important pineries of the eastern States are in Maine, where this species occurs scattered through the deciduous forests, and where the most easily accessible trees of large size have already been pretty well thinned out; Michigan and Wisconsin are the chief producing States of the western and north-western region. Saginaw Bay, on Lake Huron, may perhaps be designated as the headquarters of the north-western pine lumber industry. The somewhat less valuable southern pine (P. palustris), called also hard, yellow, long-leaved, and Georgia pine, is, in contrast with the white pine, decidedly southern species, ranging from southern Virginia south to Florida, and south-west through the Gulf States to the valley of the red River in Louisiana and that of the Trinity in Texas. It occurs over extensive areas almost entirely unmingled with other species, occupying the so-called "pine barren" zone of the southern Atlantic States, of especial importance in North and South Carolina and Georgia. The wood of this tree is heavy hard, and tough. It furnishes almost all the tar, pitch, rosin, and spirits of turpentine used in the United States. Another important pine P. mitis, the yellow, short-leaved, or bull pine, ranges from Staten Island south to western Florida, through the Gulf States and Tennessee to eastern Texas, and west of the Mississippi into Kansas and Missouri, reaching its greatest development in western Louisiana, southern Arkansas, and eastern Texas. It is an important tree in the southwest, and west of the Mississippi, and among the yellow pines only inferior in value of P. palustris. Another important conifer, next to Pinus palustris the most characteristic tree of the south-eastern coast timber belt, is the cypress (Taxodium distinchum) which ranges from Delaware south along the coast to Florida, and south-west to Texas, forming extensive forests in the southern Atlantic and Gulf States, and also extending up the Mississippi to southern Illinois and Indiana. The cypress is a marked feature in the swamp country which extends along the coast from Virginia through North and South Carolina, of which the Great Dismal Swamp, on the borders of Virginia and North Carolina, may be taken as the type. These swamps are locally known through the region where they occur as "dismals" or "pocosins." The largest continuous area of swamp in North Carolina lies between Albemarle and Pamlico Sounds, covering an area of nearly 3000 square miles. The prevalent growth of the best swamp lands is the black gum (Nyssa sylvatica), tulip tree or poplar, cypress, ash, and maple, the proportion of cypress increasing as the soil becomes more peaty. These so-called swamps-in large part at least- differ essentially from what is usually called a swamp, being considerably elevated above the adjacent streams; they are, in fact, in accumulations of decaying vegetation often peaty in character with more or less fine sand intermingled, and with a very considerable variety of forest vegetation. Portions of these swampy areas have been successfully drained and brought under cultivation; other portions have resisted all attempts of the kind, although there has been a large amount of money expended in endeavoring to reclaim them. besides the pines, there are to be mentioned here the spruces, firs, larches, and cedars, which together form a marked zone of vegetation decidedly northern is character, extending through the northern part of New England, through Canada to the Upper Lakes, and far to the north and north-west, where it unites with the forest belt of the Rocky Mountains, in almost the extreme northerly extension of this range within the United States. The northern forms of coniferous trees also occur in the highest portion of the Appalachians as far south as North Carolina, and are found along the most elevated ridges of the Rocky Mountain range, from the extreme north through to Arizona and New Mexico, and along the culminating portion of the Sierra Nevada nearly to the southern border of California. One of the most characteristic of these northern trees is the balsam fir (Abies balsamea), which ranges from Labrador north-west to the base of the Rocky Mountains, occurring in central Michigan, along the north shore of Lake Superior, and in the more elevated and damper portions of the Appalachians south to Virginia. This is the tree which produces the "Canada balsam." There are two species of spruce which have about the same range as the species last mentioned, the black spruce (Picca nigra) and the white spruce ( P. alba.). The hemlock (Abies Canadensis) is another very characteristic tree of the northern forests, where perhaps more than any other tree it sometimes occurs in "groves" or over areas of considerable size to the almost entire exclusion of other species. It is met with along the higher Appalachian ranges, south as far as Alabama; and, although it is much more abundant at the north than at the south, the largest specimens of it are said to be found in the high mountains of North Carolina. The bark of this tree is the principal material used in the northern States in tanning. The larch ( larix Americana), much more commonly called the tamarack or hackmatack, is another very characteristic northern species, although, like most of the others, ranging to a considerable distance south along the higher regions of the Appalachians. Swampy areas, over which water stands during a considerable part of the summer, are often covered with a sparse growth of this species, to the almost entire exclusion of others trees. These swamps, which are especially common in portion of the upper peninsula f Michigan, are usually known as tamarack swamps. The white cedar or arbor vitae (Thuja occidentalis) is a very common species in the north, and is much cultivated as a hedge and ornamental tree. Large swampy areas in the north, especially in the region south of Lake Superior, are covered with a gnarled and tangled growth of this species, and are called by the English-speaking population "cedar swamps," and by the French voyageurs "savanes." In the farthest north-western regions of the United States, as, for instance, on Isle Royale and the adjacent shore and islands of Lake Superior , the dwarfed and tangled growth of the characteristic northern conifers makes traveling difficult and vexations. It is sometimes, for long stretches, almost impossible to get over the ground except by crawling on hands and knees. The white cedar (Chamaecyparis sphaeroidea, more commonly known as Cupressus thyoides) is a tree pretty closely limited to the Atlantic and Gulf coast region, having its maximum development in the southern Atlantic States. It is one of the characteristic trees of the southern swampy belt.

Passing to the consideration of the western or Cordilleran side, we begin with the narrow, but in part densely forested, belt of the Pacific coast. In this connection notice will be taken of the distribution of the forests of the Rocky Mountains; for, although the two regions are separated over several degrees of latitude by the intervening region of the Great Basin, where forests are extremely scantily distributed, there are many points of resemblance between them, especially in their northern extension. In the size and density of growth of some of the species, and in the grandeur of the forest scenery generally, portions of the Pacific coast belt surpass anything else that the country has to offer. This region of dense forest growth begins on the western slope of the Sierra Nevada, at the southern extremity of the range, continuing north along that slope into the Oregon and Washington Territory, where, in the region adjacent to Puget Sound, the forests are most remarkable for their density, as well as for the size and elevation of the individual trees. The most widely distributed and most valuable of the trees of this belt is the Douglas fir (Pseudotsuga Douglasii), which ranges from British Columbia south through the Coast mountains, and along the western slope of the Sierra Nevada to Arizona, and south-east along the Rocky Mountains through Montana, Wyoming, and Colorado, but not through the Great Basin. It often forms extensive forests, especially in the northern region, where it attain its maximum development. Its wood is extensively used on the Pacific coast, the headquarters from which it is supplied being the region adjacent to Puget Sound, where it grows to twice or three times the height it has in the Rocky Mountains. The yellow pine (Pinus pnderosa) ranges from British Columbia south along the Cascades and Sierra Nevada to Mexico, and occurs, irregularly distributed, along the Rocky Mountains from Montana, where it is quite abundant, to Arizona. For size and height this species, as well as the Douglas fir, is remarkable. Its wood is variable in character, but is largely used where a better quality cannot be obtained. The sugar pine (P. Lambertiana) occurs in abundance on the western flanks of the Cascades and the Sierra Nevada, and is especially well developed in the central portion of the latter. It is one of the most conspicuous of the species which make up the grand forests of that part of the Sierra which lies at an altitude of from 2000 to 7000 feet above the sea. The digger one (P. Sabiniana) is the characteristic tree of the foot-hills of the Sierra Nevada. It is remarkable for the large size of its cones, the seeds of which were formerly an important article of food for the aborigines. A characteristic tree of the California Coast ranges, similar in many respects to P. Sabiniana, and also having large and beautiful cones, with very long, sharp, recurved points, is P. Coulteri. The wood of these two species is of little value except for fuel. Other Coast range pines of interest are-the Monterey pine (P. insignis), a tree peculiar to the sea coast, from Pescadero south to San Simeon Bay, and the Obispo pine (P. muricata), limited to the Coast ranges, from Mendocino south to San Luis Obispo. The pines of the high mountain region are – P. monticola, occurring in the Sierra Nevada at an altitude of from 7000 to 10,000 feet, and common in the northern part of the Rocky Mountains, as well as in the Cascade range, and in portion of the mountainous region of Idaho, where it is an important and valuable tree, and is sometimes called the white pine; P. flexilis, a tree occurring in limited numbers in the highest parts of the southern High Sierra of California, and here and there south along the higher portions of the Rocky Mountain ranges and also in the Great Basin, from Montana south to Arzona; P. albicaulis, by some considered a variety of P. flexilis, by others distinct species, and having a similar range with that species; P. Balfouriana, and P. Balfouriana, found about Mount Shasta, at from 5000 to 8000 feet in altitude, and around the base of Mount Whitney, also occurring in the very highest portions of the Rocky Mountains, and in parts of the Great Basin south to Arizona; P. Jeffreyi, by some considered a variety of P. ponderosa, reaching its maximum development in the Sierra Nevada, and occurring throughout the whole length of that range at high elevation; P. contorta and P. Murrayana (the latte often confounded with the former, and by most botanists considered as a variety of it), a common species on the High Sierra at from 8000 to 9000 feet in altitude, extending into Oregon and through the Rocky Mountains south to northern Arizona. Two trees, limited in their occurrence to California, and of great interest on account of their size and beauty, belong to the genus Sequoia,- the red-wood (S. senpervirens) and the big tree (S. gigantean). The redwood occurs quite close to the coast, in a narrow almost uninterrupted, belt, from a point in the Santa Lucia range about fifty miles south of Monterey to very near the north line of the State. North of Russian river this tree forms an almost unbroken forest, extremely grand in character, indvidual trees rising to nearly 300 feet in height. The big tree occurs on the western slope of the Sierra in somewhat isolated groves or patches always intermingled with other trees, and not forming forests by itself as the redwood does. Its range is from 36o to a little beyond 38o N.lat., there being nine groves, the largest of which is about thirty miles north-north-east of Visalia, on the tributaries of King’s and Kaweah rivers. The groves in Mariposa and Calaveras counties are those most visited by tourists, and in the latter is the tallest of these trees, and the tallest tree on the American continent, so far as known (325 feet). Another conifer of much interest from its beauty and its very limited range is the Monterey cypress (Cupressus macrocarpa), a species occurring only on Cypress Point, near Monterey. The Port Orford cedar (Chamaecyparis Lawsoniana), a strictly Pacific Coast species, ranging from Coos Bay in Oregon into northern California, is a large and valuable tree, with an odoriferous, highly resinous wood. The white cedar of the pacific coast (Libocedrus decurrens, called by some botanists Thuja gigantean) is also a Pacific Coast species, ranging from the Santiam river in Oregon south through the Coast ranges as far as Mount San Bernardino. The Thuja gigantean proper, or red or canoe cedar, is another Pacific Coast range tree; but, unlike the two species last mentioned, it extends its range into the northern Rocky Mountain region. It is a large tree, which has its maximum development in the Coast ranges of Washington Territory and Oregon.

The deciduous trees of the Sierra Nevada and the Cascade range, as well as of the Pacific Coast ranges from California north to the boundary line, are of comparatively little importance. There are several species of oak, but of little value, - among them being the Coast live oak (Q. agrifolia), the largest and most generally distributed oak in the south-western part of the California; the black oak (Q. Kelloggii), ranging along the coast mountains of Oregon, and the most characteristic hardwood tree of the western slope of the Sierra; and the chestnut oak (Q. densiflora), occurring in the Coast ranges from Oregon to central California. An evergreen tree, very characteristic of the coast ranges of Oregon and California, and very ornamental, is the California laurel (Umbellularia californica), of which the wood is hard and strong, and of a very pleasing light-brown mottled color. The tree called the madrona or mandrono (Arbutus Menziesii) occurs from British Columbia south through the Coast ranges to the Santa Lucia Mountains, and is a very characteristic tree of the region, with its red bark and beautiful glossy foliage. The wood is used in the manufacture of gunpowder, and the bark to some extent in tanning.

In the area included between the two heavily-timbered regions described above, or between the summit of the Sierra Nevada and Cascade range and the western border of the great eastern forest region, the paucity of rainfall corresponds to paucity or almost entire absence of forests over much the larger portion. We may here distinguish, first, the Rocky Mountain region; then the Great basin and the plateaus north and south of it; then the "Plains," or the nearly level country lying east of the base of the Rocky Mountains; and, finally, the "Prairie" region, or that portion of the scantily timbered area which for the most part lies enclosed within the eastern forested belt, and where other causes than the absence of moisture have operated to bring about the growth of a peculiar vegetation.

The Rocky Mountain belt is not destitute of forests, but these are very irregularly scattered over the surface, and the species are few in number, chiefly belonging to coniferous genera, and of little economic value. The species of conifers have been already mentioned, and their range indicated in speaking of the forests of the Sierra Nevada and Cascade range. Few forests in the Rocky Mountains at all compare in density or in the size of the individual trees with those of the Sierra and the Cascade range. What trees there are usually grow most densely in the moist places at the foot of the ranges, where the streams debouch from them, in the ravines and gorges, and on the lower slopes. By far the most common deciduous tree throughout this region is the aspen (Populus tremuloides), often called cottonwood and sometimes poplar, which most commonly springs up, forming dense thickets, throughout the Rocky Mountains, wherever the coniferous forest has been burned off. It ranges from Newfoundland to Arizona, and is the most widely distributed of North American trees, and highly characteristic of northern and elevated regions. In various portions of the Rocky Mountains there are scattered oaks. The scrub oak (Q undulata, var. Gambelii) occurs in some quantity on the mountains of southern New Mexico and Arizona, and is also found in Colorado and along the Wahsatch range. The black oak (Q Emoryi), the white oak (Q. grisea), and a few other species are pound here and there in the southern part of the Rocky Mountains, as also in Arizona, and ranging south into Mexico. The most densely forested portions of the Rocky Mountain are the extreme northern in north-western Montana, the north-west corner of Wyoming, the higher part of Colorado, the eastern slope of the range in New Mexico, and the higher portions of Arizona.

Enclosed between the densely-forested Pacific belt and the poorly-timbered region of the Rocky Mountains is an extensive area, including the northern and southern plateaus and the Great Basin, which practically is nearly destitute of trees. the coniferous species occurring in the Rocky Mountains are found here and there along the moister tracts of the higher ranges in the Great Basin especially in its eastern and higher portion, but fly far the larger part of the slopes and nearly all the valleys are treeless, being chiefly occupied by the well-known sage-brush" (Artemisia tridentate),which covers many thousands of square miles, especially in Nevada and Utah. Two trees are, however, very characteristic of the Great Basin, especially of its western portion –the juniper (Juniperus occidentalis) and the pinon or nut pine (Pinus monophylla). These two species, usually much dwarfed in size and scrubby in appearance, are almost the only trees of western and central Nevada, where they occur hidden away in the canons. Everywhere in a wide sweep adjacent to the mining districts all this vegetation has been completely cleared away.

An order of plants peculiarly American, and characterizing in a most marked manner the hot dry region adjacent to the lower Colorado, is that of the Cactaceae. The cactus ranges from the extreme north of the plateau region to the extreme south, but its most abundant and striking development takes place in southern Nevada, southern California, and in general the region adjacent to the Mexican boundary line. The so-called prickly pear (Opuntia) is the cactus family which has the widest range, being found from the upper Missouri through the Great Basin to Arizona. It has many species, that which ranges farthest north being O. missouriensis. The genera Mamillaria Echinocactus, and Cereus are found in various localities in the Great Basin, as well as in southern Califronia, in portions of which region, as well as in lower California and Arizona, there are large areas where various kinds of cactus form almost the exclusive vegetation, often rising to such a height as to be properly called trees; the loftiest of all is the singularly striking Cereus giganteus. Mingled with them are yuccas (called the "Spanish bayonet"), mesquites (Algarobia glandulosa), and the creosote bush (Larrea mexicana), which are among the most abundant and characteristic plants of this region.

The vast area extending east from the base of the Rocky Mountains to near the 95th meridian is the district universally known as "the Plains," and one not at al to be confounded with the "Prairies," which are almost entirely included within a region of dense forests, and over which the partial absence of trees is due to a cause entirely different from that which has made the plains the home of the grasses and not of trees. the transition from the forested region of the east to the region of the plains is, almost without exception, coincident with the diminution in the precipitation, which as we proceed westward goes on rapidly, and, on the whole, pretty regularly. Thus Dakota, between 97° and 104° W. long., is practically destitute of timber, except in its river bottoms and the small territory between the north and south forks of the Cheyenne, the region of the Black Hills. In Minnesota, which lies east of 97°, only the north-eastern portion, especially that adjacent to Lake Superior, is heavily timbered. The south-western corner of the State, embracing about one-third of its area, and the area west of the 96th meridian, are classed in the census report as having less than two cords of wood to the acre. Nebraska and Kansas, still farther south, are almost destitute of forests. In Nebraska only a narrow strip along the Missouri, near the meridian of 96°, is given as having from one to two cords of wood per acre. The heavy forest growth of the Mississippi basin just reaches the extreme south-eastern corner of Kansas. North of this, and along the eastern border of the State, there is a belt of from thirty to a hundred miles in width in which there is valuable timber on the borders of the streams. West of 97° W. long. The trees are confined to the immediate banks of the large streams, and are small and of little value. West of 99° we find the typical vegetation of the plains, with only a few small stunted willows and cottonwoods scattered at wide intervals along the streams. The yearly isohyetal of 26 inches forms a limit beyond which arboreal vegetation is almost entirely absent, while in going east there is little of value until we reach the belt in which the rainfall is over 32 inches. The same may be said of the Indian Territory and Texas, the bending of the isopyetal curves to the west as we approach the Gulf of Mexico being, however, as might be expected, accompanied by a corresponding extension of the forest belt in that direction. Thus, Texas, the limits of what may be designated as the well-timbered region lies between 96° and 97°, while the line marking the entire disappearance of the forests may be placed somewhere between 99o and 100o, and pretty closely adjacent to the isophyetal of 26 inches.

The French word "prairie," a meadow or grassy plain, was employed by Hennepin about 1680, in his excellent description of the prairies of Illinois. The word has become current in the Mississippi valley, and still farther west. In the northern portion of the Rocky Mountains the small grassy areas adjacent to the streams and surrounded by mountains are called "prairies," while farther south they are known as "parks," the still smaller areas being frequently denominated "holes." In general, however, the term prairie is used to designate tracts of land nearly or quite destitute of forests, or over which the trees are, as a general rule, limited to the "bluffs" – the more or less precipitous slopes which separate the upland, or prairie proper, from the river bottom-which treeless areas occur in the midst of well-forested country. Illinois is par excellence the Prairie State, and may be considered the center of the prairie region, the adjacent States, on all sides, having more or less prairie and also areas of dense forest.

All through the prairie region the precipitation is abundant and pretty equally distributed through the year. The vicinity of Chicago, a typical prairie region, comes within the isohyetal of 44 inches and upwards, and the same is true of a part of the treeless region of Iowa. Large areas in the more southern States – Arkansas, Alabama, Mississippi, and Louisiana – are also prairies, portions of which are entirely destitute of forests, while others have small ‘clumps" of trees sparsely scattered over their surface. This is in a region of the largest rainfall, that of 56 inches and upwards. The cause of the absence of trees on the prairies is the physical character of the soil, and especially its exceeding fineness, which is prejudicial to the growth of anything but a superficial vegetation, the smallness of the particles of soil being an insuperable barrier to the necessary access of air to the roots of a deeply-rooted vegetation. Wherever in the midst of the extraordinarily fine soil of the prairies coarse or gravelly patches exist, there dense forests occur. The theory that fineness of soil is fatal to tree growth finds its most remarkable supports in the fact that in south-eastern Russia the limits of the "black earth" and the treeless region are almost exactly identical, and not at all in harmony with the position of the isophyetal lines. The black soil of Russia is an earth of exceeding fineness – so fine indeed that it is with the greatest difficulty that the air can penetrate it so as to oxidize the organic matter which it contains, - the essential cause (in the opinion of the present writer) of its dark color. The peculiar mode of decay of the organic matter in such soils seems analogous to that by which vegetation has been turned into coal or lignite when so buried under detrital material as to greatly impede the access of the air. it is now easy to see why plains are likelier than mountain slopes to be treeless, it being towards the plains that the finer particles of the material which is abraded from the higher regions are being constantly carried. The more distant the region from the mountains and the broader its area more likely it is that a considerable portion of it will be covered with fine detritus, whether this be of subaerial origin or deposited at the bottom of the sea. The exceedingly fine soil of the typical prairie region consists, in large part, of the residual material left after the removal, by percolation of the rain and other atmospheric agencies, of the calcareous portion of the undisturbed stratified deposits, chiefly of Palaeozoic age, which underlie so large a portion of the Mississippi valley. The finer portions of the formations of more recent age in the Gulf States have also, over considerable areas, remained treeless. There are in various parts of the country beds of lakes which have disappeared in consequence of their very slow filling up with fine sediment, and these are not occupied by the forest, although surrounded by the densest arboreal growth.

The principal use of the forests of the United States is for fuel; and there is no part of the settled portion of the country where the consumption for this purpose is to of some importance. In the middle and northern Atlantic States coal is the chief fuel in the cities and large towns, and the almost exclusive fuel of the larger cities on important lines of communication, but supplemented, to a greater or less extent, by wood. But in the country, on the farms, and in the small towns wood is almost exclusively used, except on the coal-fields or in their immediate vicinity. In the coal-producing States and Illinois and Iowa, where forests are limited to certain areas, and in Nebraska and Kansas, which have coal of inferior quality and where forests are still scarcer than they are in Illinois and Iowa, coal is the dominating fuel. The same is the case in certain of Missouri. In all the States south of Virginia and Kentucky wood is almost the exclusive fuel, except in a few of the very largest towns. Wood is also almost exclusively the material of which houses and barns are built over the whole United States, the exceptions being the larger cities (chiefly of brick, with some stone), the business portions of the towns of second rank, and occasional important buildings in towns of the third rank. The other uses of wood are obvious. The following figures given by the census of 1880 relate to the manufacture of sawn lumber;- establishments, 25,708; capital, $181,186,122; average hands employed, 147,956; feet of lumber produced, 18,091,356,000; laths, 1,761,788,000; shingles, 5,555,046,000; staves, 1,248,226,000; sets heading 146,523,000; feet of bobbin and spool stock, 34,076,000; total value of specified products, $230,685,061; value of other products, $2,682,668; total value, $233,367,729. The consumption of wood for domestic fuel is given in 1880 as amounting to 140,537,439 cords, with an estimated vaue of $306,950,040, and the total consumption of wood as fuel as 154,778,137 cords, valued at $321,962,373.

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