18 
be dissociated from the moisture requirement, atmospheric movements 
and soil character being the chief of these. It may be safely assumed 
that the line of successful tree culture will be moved westward in even 
pace with the agricultural development of the country, and but little, 
if any, in advance of it. The clay soil of the plains, protected with but 
a scant growth of herbage, undisturbed through centuries beneath the 
burning sun and almost constant wind, compacted by the hoof beats of 
countless buffalo, can not be as absorbent as it will be when the plow 
has turned it, and frost has disintegrated it, and the deep growing 
roots of alfalfa have made it permeable to moisture. Wherever large 
areas have been brought into cultivation, tree culture has been more 
successful than before the advent of the plow. The prairies of Illinois, 
Iowa, and the eastern parts of Kansas and Nebraska with their planted 
eroves fully sustain this view. The area of successful tree culture in 
the West can be demonstrated only by test plantings. Even should 
failure attend these at first, it must be borne in mind that the methods 
employed or the material selected may be responsible for the results 
quite as much as any lack of moisture. 
In the past two years, since the planting experiments herein recorded 
were begun, the rainfall during the growing season, March to October, 
at Manhattan, Kans., has been for 1896, 34.24 inches, quite evenly 
distributed throughout the season; for 1897, 20.51 inches, with only 
1.4 inches in August and September. The average rainfall at this 
station for the months March to October, inclusive, for the past forty 
years has been 24.02 inches, distributed by months as follows: March, 
1.52inches; April, 2.78 inches; May, 4.08 inches; June, 4.46 inches; July, 
4,65 inches; August, 3.52 inches; September, 2.95 inches; October, 2.26 
inches: an amount which both in quantity and distribution would lead 
one to anticipate, what experiments thus far indicate, suitability of 
soil moisture for quite a number of varieties of trees of the Eastern 
forest region. At Lincoln, Nebr., the rainfall for the same period in 
1896 was 24,22 inches, and in 1897, 21.73 inches, and a reference to the 
record of growths at that station (see page 59) indicates this to have 
been ample for the needs of most of the species tested. 
At Brookings, S. Dak., the rainfall for the same period in 1896 was 
19.1 inches, and for 1897, 20.55 inches, and here again a reference to 
the measurements of growth (see page 69) indicates sufficient moisture 
for the needs of the trees. At the stations of Fort Collins, Colo., and 
Logan, Utah, the tree plats were irrigated, and were therefore inde- 
pendent of rainfall. 
SOIL AND SOIL MOISTURE. 
The amount of rainfall is not necessarily an indication of the moisture 
of the soil, and hence of the amount of water available for the roots of 
the trees. A heavy rain might fall on compact, sun-baked soil, such as 
is common over extensive areas of the West, and by far the greater 
part of the water would run off and be lost to vegetation because the 
