Excerpts from Eight Months in Illinois
By William Oliver, 1843
Prairie Soils
"Illinois is free from anything deserving the name of hills; there are, however, very considerable inequalities, occasioned by the cutting down of the water courses, and the surface of the prairie is frequently what is termed rolling, displaying a succession of easy swells, which at a short distance assume the appearance of an even surface, and the stranger is often startled by the appearance of a herd of cattle or horses, as it were, rising out of the earth, or quietly grazing, where a minute before his eye had wandered over the unvaried ocean of grass.
"Prairie consists of almost every variety of soil, from a rich impalpable
loam to sterile gravel or sand; I believe there is little of the latter description
in Illinois. The rolling is generally the best; that feature evidently being
the cause of the superiority, as it facilitates the drainage of the surface
of the country, and induces a more abundant growth and deposit of vegetable
matter. The flat prairie is apt to be wet, or, as the natives term it, slashy,
if not connected to some watercourse, by which the water may escape, on the
subsidence of the spring freshets; and on being suddenly dried out by the
sun, at the commencement of summer, is so hardened as to produce little grass,
and on that account, is less liable to be run over by the annual forest fires,
and is deprived of the rich black deposit, which, there can be no doubt, is
the result of these variations. As a general rule, the higher the prairie
is, the better is the soil."
Pages 57-58, SIU 2002 edition
Speculation on the Lack of Timber on the Prairie
"The question of the prairies having no timber upon them, is, I think,
nearly set at rest, if we allow that they formed the bottom of a lake or lakes,
whose waters were somewhat suddenly drained away. The exposed surface would
be the depository of a variety of winged seeds of weeds and grass, and it
is natural to suppose that a rank vegetation of such products would ensue
long before the heavier seeds of trees had advanced any considerable distance.
It is not necessary to suppose that man existed at eh period alluded to, in
order to account for the periodical fires, for I have heard it affirmed by
people of veracity, that, independently of human agency, the prairie is frequently
set on fire by lightning; and when we know that hay and straw are readily
set on fire by that fluid, we may admit that a thick crop of prairie grass,
rendered almost as susceptible as tinder by the clear dry autumn of the climate,
may be ignited by the same means.
"That the annual conflagrations have prevented the growth of timber on
the prairies, is clearly provided by the very vigorous growth of young wood
which takes place along their margin, wherever the fire has been kept out
for a few years, and in this country, where vegetation proceeds with a rapidity
quite astonishing to the native of Britain, many kinds of trees, at the age
of three or four years, have attained a height of from eight to twelve feet.
Fire will pass through among trees of even smaller dimensions that these without
killing, although it materially injures them, and on the ridges and in the
groves, which, from their situation, must have been frequently exposed to
fire, the old timber is invariably unsound, and much of it is hollow."
Pages 61-63, SIU 2002 edition