FORESTS AS A FACTOR IN SHAPING 



THE PHYSIOGRAPHIC FORM OF 



MOUNTAINS 



BY 



J. W. TOUMEY 



Professor of Forestry, Yale Forest School 



HPHE effect of forest cover upon the surface flow of 

 water has been for many years an inviting field 

 for speculation and research, both in this country and 

 abroad. Since the extended researches of Ebermayer 

 of Bavaria, more than a quarter of a century ago, most 

 writers in this field have placed special emphasis upon 

 the effect of forests in providing a larger and better 

 absorbing medium. It has been argued that the chief 

 influence of the forest upon the flow of streams, lies in 

 the fact that it provides a looser and deeper soil, cov- 

 ered with a variable depth of humus and litter, into 

 and through which the precipitation freely seeps. 

 Therefore, a much larger part of the rainfall is taken 

 up by forest soil than by soil in the open, and there 

 is less to pass directly into the streams by flowing over 

 the surface. As a result, the flow of streams in fo; 

 ested regions are more sustained than similar stream 

 flowing from naked drainage basins. 



There is at the present time no serious opposition 

 to the view as here set forth. In recent years, how- 

 ever, special emphasis has been placed upon the follow- 

 ing, viz., that the proportion of the rainfall that reaches 

 the streams and the manner of its reaching them de- 

 pends chiefly upon the physiographic features of the 



