ApRit 11, 1884. |] 
that, although herbaceous plants may grow 
abundantly upon it, forest-trees cannot thrive. 
Others, again, suppose that the absence of trees 
upon the prairies is due to climatic causes, and 
that the growth of trees upon them by artificial 
planting will therefore always be precarious or 
impracticable. A large number of men, with no 
theory to support, who have made their homes 
in the great prairie region, have demonstrated 
by actual experiment that forest-trees will grow 
thriftily and to full maturity upon its soil. 
It is my present purpose to speak of this 
success, and of the indication which it gives 
that the great prairie region of the United 
States may be made to produce the wood for 
all the needed fuel of the inhabitants, and also 
for other economic uses. Before doing so, 
however, it is desirable to describe that region 
briefly, as it existed when it was first occupied 
by white men, and to indicate in a general way 
its limits and its relation to adjacent regions. 
It is difficult to define the boundaries of the 
prairie region as it existed then: first, because 
it merged, on the one hand, into the woodland 
regions, and, on the other, into the great arid 
plains of the west; second, its original char- 
acteristic features have been so changed by 
cultivation, its occupancy by homesteads and 
villages, and by the increasing presence of 
trees of both natural growth and artificial plant- 
ing, that one now rarely gets sight of typical 
prairies as they existed over so large a region 
only a few years ago. 
In the middle and Gulf states there were 
originally numerous treeless areas, which were, 
properly speaking, prairies ; but to these I do 
not now refer. It is sufficient for my present 
purpose to say that the states of Illinois and 
Jowa lie in the heart of the region I shall dis- 
cuss, and that it also embraces large adjacent 
parts of Wisconsin, Minnesota, Dakota, Ne- 
braska, Kansas, and Missouri. 
Although this region occupies a central posi- 
tion upon the continent, its average elevation 
is not great, a part of it being less than five 
hundred feet above the level of the sea. The 
general surface has an approximately level as- 
pect; but it is often undulatory, and sometimes 
cut by deep valleys. It is traversed by two 
great rivers, the Mississippi and Missouri, and 
also by many of their tributaries. The val- 
leys of these streams are cut down somewhat 
abruptly from the general level, to depths vary- 
ing from a dozen feet to two or three hundred 
feet. The streams are bordered by level ‘ bot- 
tom-lands,’ varying in breadth from a few rods 
to several miles. 
These bottom-lands and the adjacent valley- 
SCIENCE, 
459 
sides, together with the contiguous ravine- 
broken land, contained all, or nearly all, the 
forest-trees which grew in that great region 
when white men first knew it; and even these 
surfaces were then largely destitute of trees. 
All the broad intervening spaces were covered 
with a dense growth of grass, mingled only 
with other herbaceous plants. So small was 
the aggregate of the timbered as compared with 
the grass-covered surfaces, that, from a long 
and early acquaintance with it, I estimate the 
former to have been not more than five per cent 
of the whole. In many parts of the region it 
was certainly less than this. 
The early settlers found the Indians in the 
habit of burning the prairies annually; and 
they seemed to have practised that habit from 
time, to them, immemorial. The grass of this 
creat region was largely burnt off every year, 
either by accident or design; so that from 
October until May the settlers were seldom 
out of sight of the lurid light of the burning 
orass by night, or the towering volumes of 
smoke by day. ‘The next spring brought an 
equally abundant growth of grass from the 
unharmed roots, to fall, in turn, a prey to the 
devouring flames. 
Although that condition of things prevailed 
within the memory of thousands of persons 
now living, the present prevalence of artificial 
groves, and the rapid natural encroachment of 
trees upon the before treeless surfaces, which 
followed the discontinuance of the annual fires, 
have nearly destroyed all the distinguishing 
characteristics of a prairie region. So rapidly 
is this change now taking place, that the next 
generation of those who are to occupy it will 
probably know of its original prairie character 
only from tradition or history. 
The prairie region in question lies almost 
wholly within that over which the great north- 
ern drift is distributed ; and its soil and sub- 
soil are largely made up of the drift material, 
together with the silt deposit to which the 
name of ‘loess’ is now generally applied by 
geologists. The soil is therefore quite uniform 
in character over large portions of the region, 
and yet there is a good degree of variation in 
different localities. Itis generally arich, deep, 
dark loam, often without a stone or pebble in 
sight for many miles. But sometimes drift 
pebbles and bowlders are scattered plentifully 
upon the surface ; and, in the valley-sides, es- 
carpments of the underlying stratified rocks 
often appear. 
To the westward of the Missouri River the 
prairies pass gradually into the great plains ; 
and these continue westward to the base of the 
