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TREELESSNESS OF PRAIRIES.
[ To Prof. Winchell, L. L. D., Professor of Geology and of Botany, in University of Michigan, we are indebted for the following interesting contribution:]
The prairies of the Mississippi valley, especially those lying within the limits of the great State of Illinois, constitute one of the most remarkable features of North American topography. Hundreds of thousands of acres, stretching through all the central and western portions of the State, present a scene of almost unbroken level and treelessness. The great prairies are neither a perfect plain, nor in all cases completely undiversified with arboreal vegetation. The surface is generally undulating, and here and there rise gravelly knolls and ridges on which the timber has obtained a foothold. But these wooded spots are often many miles apart, and scarcely serve to rest the eye, wearied with the monotony of an interminable view of fenceless meadows and unsheltered farm houses.
The traveler, leaving Chicago by one of the great southern routes, passes out through the muddy and straggling outskirts of the western metropolis, and, ere he had thought of the great prairies through which he had expected to pass, he finds himself at sea. Looking from his car window, the country landscape seems at first to be entirely wanting. He feels as if passing over a trellis bridge, three hundred feet above the surrounding region. The customary
. objects-forests, shade trees, fences, houses, distant hills—which elsewhere lift themselves to the horizontal plane of the eye, are not here. The traveler must make a second effort, and look down upon the level of the country upon whose bosom he has now launched. The sensation is that which one experiences when going to sea. The rattling of the train is easily transformed into the puffing and creaking steamship, while the interminable prairie, mingling its distant and softened green with the subdued azure of the summer sky, can be likened to nothing but the ocean's boundless expanse. The ever recurring undulation of the prairie is the grand ocean swell, which utters perpetually a reminiscence of the last storm, while the evening sun, with dim'd lustre, settles down into the prairie's green sod, as to the mariner he sinks into the emerald bosom of the sea.
“These are the gardens of the Desert—these
The sunny ridges.” Illinois has been styled the garden State of the West. The deep rich pulverulent soil of the upland prairie, and especially its readiness for the plow, without the intervention of a year's hard labor in opening "a clearing,” have always constituted powerful attractions for the settler from the stony hills of New England, and the wooded regions of other States.
From our earliest knowledge of the prairie, speculation has been rife as to their treelessness and origin. The old and popular belief was that which attributed their treelessness to the annual burning of the grass by the Indians. But the prairies present other phenomena, which the annual burning fails to explain besides; the treelessness remains in regions where the burnings have ceased. And, further, the treeless prairies were not the only regions burnt by the Indians. And if they were, it seems more likely that the Indian. burned the rank grass because the region was treeless than that the
region became treeless from the bụrning of such vegetation as flourishes in the shade of a forest.
It has been suggested that the region was originally forest-covered, and that the southern cane flourished in such luxuriance among the trees as to rob them of their moisture and nourishment, and thus caused their extinction, and the cane having deprived itself of the forest shade and protection, was itself scorched out by the rays of the summer sun. This theory is in every way unsatisfactory.
With others, the absence of trees is to be attributed to the absence of moisture in the atmosphere, and also of the soil at certain seasons of the year. It cannot be doubted that the treeless plains of the far west, and also other regions, have failed to produce arboreal growths through an insufficient supply of moisture. Still other treeless regions are such from an excess of saline constituents in the soil. But all such regions have nothing in common with the prairies of Illinois, except their treelessness. The topography and
, soil constitution of Illinois prairies points to a different and peculiar history. Moreover, trees occupy the dryer knolls of the prairies in the midst of common atmospheric conditions.
Exactly the reverse of this theory is that which attributes the absence of trees to an excess of moisture in the soil at certain sea
But we well know that there is no soil so wet and stagnant but certain trees will flourish upon it—the willow, the cottonwood, the beach, the black ash, the alder, the water oak, the American larch, the arbor-vitæ, or some other tree-some of them standing joyously half the year, if need be, in water most stale and stagnant. Many swamps and sloughs are, indeed, treeless, but is this in consequence of the inability of the willow to take root and maintain itself, or rather in consequence of the formation of the swamp so recently that the germ of the tree has not yet been scattered over it? Moreover, wetness cannot be attributable to large portions of Illinois prairies which are entirely treeless. Is there a different cause for treelessness here? It has been suggested within a few years by high geological authority, that the lack of trees is caused by excessive fineness of the prairie soil. It can scarcely be denied however that other soils, as pulverent as that of the prairies, are densely covered with forest vegetation, and that in the same latitudes, and under the same meteorological conditions. On the other hand certain soils of a coarse texture, are equally treeless. But the final
objection to this theory, and to all other theories which look to the physical or chemical condition of the soil, or even to climatic pecu. liarities, for an explanation of the treeless character of the upland prairies of the Mississippi valley, is discovered in the fact that trees will grow on them when once introduced—not water-loving trees exclusively, but evergreens, decideous forest trees and fruit trees, such as flourish in all arable soils, and habitable portions of our country. Every one will now admit that trees will flourish upon prairies. In proof of this fact the prairie farmers for many years have been actively and successfully engaged in their introduction. “The prairies,” says a noted author, “may easily be converted into wooded land by destroying with the plow the tough sward which has formed itself on them. There are large tracts of country where, a number of years ago, the farmers mowed their hay, that are now covered with a forest of young, rapidly growing timber. In like manner, the uplands of St. Louis county, Missouri, which were, in 1823, principally prairie lands, are now covered with a growth of fine, thrifty timber, so that it would be difficult to find an acre of prairie in the county.” This testimony is confirmed by numbers of persons from various parts of the State with whom I have conversed on this subject. The introduction of timber as a branch of rural industry, is now systematically pursued. A drawback to the cultivation of forest and fruit trees, is the violence of the prairie winds, and the occasional severity of the winter weather.
There are pretty satisfactory evidences that the soil of the prairies is of lacustrine origin. It has the fineness, color and vegetable constituents of soil accumulated upon a lake bottom. We find in it, moreover, abundant fossil remains of a lacustrine character. Fresh water-shells of a species still existing in lake Michigan, are found in localities many miles from the existing shore. Finally we have found all around the chain of great lakes, abundant proofs that their waters once occupied a much higher level than at present. We have discovered the object that dammed the waters to this extraordinary height. In short, we have ascertained that the prairie region of Illinois must have been a long time inundatedwhether such inundation contributed to the characteristics of the prairies or not. I think it did. If I ascertain that the cause for an inundation exists; if I see the traces of an inundation all the way from the Niagara river to Illinois; if the barrier which shuts out Illinois from the lake is not one-third the hight of the ancient lake flood; if I find throughout the region exposed to inundation, the peculiar soil deposited by fresh waters, together with traces of lacustrine animals, which never wander over land, do I not discover a chain of facts which necessitates my conclusions? During the foodtide of the lakes, Lake Michigan must have found an outlet towards the south.
We find a corroboration of this. The broad, and deep, and bluffined valley of the Illinois river was never excavated by that inconsiderable stream. The deserted river valley discovered at intervals farther north, indicates the former southward flow of large bodies of water. At Lemont this valley is distinct, with its bounding bluffs and its "pot-holes,” worn in the solid rock of the ancient river bed. This was the work of the lake in its declining stages. At the earlier period, when the waters of Lake Michigan stood one or two hundred feet higher than their present level, how much of the region south and west of Chicago must have been submerged? The ancient lake must have reached its arms into Iowa, Northern Indiana and Southwestern Michigan. While the expanse of lacustrine waters was brooding over the region destined to become a prairie, they busied themselves in strewing over the tombs of pre-glacial germs a bed of mud which should forever prevent a resurrection. Lake sediments themselves inclose no living germs. You will see the seeds of grasses and of fruit trees washed in by the recent storm, floating upon the surface and eventually drifting to the leeshore. If they ever sink to the bottom and wrap themselves in the accumulating mud, it is after they have lost their vitality. Sunken and buried, they go to decay. Let a lake be drained and the bottom remains a naked, barren, parching, shrinking waste. No herbs, or grasses, or trees burst up through
. the pottery-like surface. But everywhere, from beds of ancient glacial materials, vegetation is bursting forth and announcing itself. “Lo! here I am!” speaks the nodding young pine, that has been slumbering just beneath the surface through the long and undisputed possession of the deciduous forest, which the axe had just mown down. Not so in a lake bottom. Here are the cerements of the dead, not the wrappings of the slumbering. When, therefore, the ancient lake relinquished dominion over Central Illinois, it left a devastated and desolate country. Around the ancient shores of the abandoned area the emerald forest had stood nodding and blossoming and fruiting, while the inundating lake had washed