FOREST AREAS AND SOIL WATER 
157 
delayed increase, during a period without precipitation, of the 
moisture content of the subsurface and even surface layers at 
the lower part of the slope. 
Consequently, these general results all lead directly to a recog- 
nition of the close relationship between forest cover and soil 
moisture content in regions like the one under' consideration here. 
They lead to the further recognition of the influence of forest 
areas of even small extent in maintaining greater quantities of 
moisture in the upper soil layers, and to their ability to prolong 
the period of gravitation of moisture, both from surface to lower 
soil strata and from upper to lower elevations on a slope. This, 
it is evident, would have a direct bearing upon the source of 
streams such as exist in the area discussed, where this source is 
largely in underground waters or springs. 
Since in even a limited area, as was included in the present 
studies, the removal of the forest cover from one of the slopes 
has had the marked effect shown, indications point strongly to 
the final influence of forests in -maintaining a higher water level 
throughout the region in general as being an exceedingly im- 
portant one. 
The writer desires to express his thanks to Dr. L. H. Pammel 
and Dr. A. L. Bakke for suggestions and criticisms in conducting 
the experiment and in preparing the manuscript. 
Department oe Forestry, 
Iowa State College. 
