20 
The influence of the structure or consistency of soils upon their 
moisture content, and hence upon tree growth, is nowhere more evident 
than along the Arkansas River. The broad bottom lands of the Arkan- 
sas consist of a rich sandy loam of great depth. The porosity of the 
soil permits the free passage of water—the water level being only 10 
to 12 feet below the surface, with no hardpan intervening. The lux- 
uriant growth of planted trees in this moist soil is phenomenal. At 
Hutchinson, Kans., there are extensive plantations of Hardy Catalpa 
which average over 20 feet in height seven years from the seed. At 
Rocky Ford, Colo., in a plantation which had not been irrigated for 
three years previous to the time it was examined by the writer, the Cot- 
tonwoods were growing as luxuriantly as along the bottom lands of the 
Mississippi in Arkansas. 
On the other hand, the effect of a stiff (hardpan) subsoil is equally 
apparent in the growth of trees. At College Station, Tex., the Brazos 
Valley is underlaid within 2 feet of the surface with a very stiff blue 
clay. The native trees on such lands are so stunted as almost to lead 
one to mistake their identity, and this, too, in a region of heavy rain- 
fall? 
Over much the greater portion of the plains the typical soil condition 
may be stated as follows: A clay-loam surface soil, varying in depth from 
1 to 3 feet, dark brown to black in color, of great fertility, underlaid 
with a moderately stiff yellow or yellowish-brown clay to a great depth. 
This clay contains considerable sand, and is frequently characterized 
by small lumps of a calcareous nature, which show white when cut 
through in digging. It is penetrable by tree roots, though not so easily 
as is the looser subsoil of the Arkansas Valley. There would seem to 
be no reason why such a soil, under proper treatment, should not sup- 
port forest growth. Its moisture-bearing capacity will undoubtedly be 
increased by the thorough cultivation of extended areas, and thereafter 
the compensatory action of forest growth will be manifest. Through- 
out the plains the soil in the bottom lands along the streams is moist 
for a much longer period than the uplands, and suecess with trees in 
the low valleys is comparatively certain. But the great need of groves 
is on the high lands, where they will act much more effectively as wind 
breaks, and where the water from the snowdrifts which they catch 
will be absorbed by the fields. Hence, wherever possible high lands 
should be selected as sites for groves, even though a slower growth 
of the trees be secured there. 
ATMOSPHERIC MOISTURE. 
The great prevalence of winds in the plains region is well known. 
Their action, generally speaking, is to increase the transpiration from 
plants and the evaporation of moisture from the soil, and they may 
thus be considered a hindrance in agriculture, to say nothing of the 
discomfort they cause. Prof. F. H. King, of the University of Wiscon- 
