THE SAND-HILL KEGION. 



13 



one year, would, if applied to the receptive soil of the sand hills, 

 undoubtedly be sufficient to sustain tree growth, if the trees were 

 already well established. Only newly planted trees are likely to 

 suffer. It is surprising how well the sand below the surface layer 

 will hold water and how readily moisture is brought up from the 

 lower depths by capillary action. While the quantity is less than in 

 a heavy soil, it varies less from season to season. In the fall of 1911, 

 after unusual drought for several months at Garden City, the very 

 sandy soil of the hilltops was found to be dry to a depth of only 8 

 inches, while in some places the more compact soils were dry to a 

 depth of 34 inches. In the Nebraska sand hills in 1911 the sand dried 

 out to a depth of about 4 inches where there was no vegetation, but 

 to a depth of from 14 to 18 inches under sod. Under these circum- 

 stances trees of the previous year's planting suffered very little. 



TEMPERATURE. 



Table 3 shows the important features with respect to the tempera- 

 ture at Halsey and Garden City. The mean temperatures at Fort 

 Robinson are also given. 



TABLE 3. Monthly temperatures at Halsey, Nebr., and at Garden City, Kans. 1 



1 From data furnished by local Weather Bureau offices at Lincoln and Topeka. 



2 Absolute maximum: Halsey, 107; Garden City, 112. 



3 Absolute minimum: Halsey, 32; Garden City, 32. 



NOTE. Length of the growing season (data from Weather Bureau Bulletin 

 Garden City, 155 days. 



HUMIDITY. 



: Q"): Ilalsey, 132 days; 



The atmospheric humidity of the sand-hill region is rather low as 

 compared with the East, but considerably higher than that of the 

 Rocky Mountain region, where coniferous forests grow naturally. 

 It can not, therefore, be said that the lack of atmospheric moisture 

 explains the lack of forests in the sand hills. The mean annual 

 humidity in the vicinity of Halsey is about 67 per cent and in the 



