172 North American Forests and Forestry- 

 has seen the absolute necessity of preserving the 

 mountain forests and has recently set aside a num- 

 ber of large forest tracts in various parts of the 

 mountain regions, to be preserved as protective 

 forests. We will, in a succeeding chapter, briefly 

 treat of some of the discussions which have arisen 

 out of the setting aside of these reservations. 



There has been some controversy on the manner 

 in which the Rocky Mountain forests act upon the 

 melting of the snow and thereby affect the irriga- 

 tion problem. It is actually argued by some that 

 the presence of forests is injurious instead of bene- 

 ficial. It is said that the forests prevent the drifting 

 of snow and its accumulation in immense heaps 

 filling the ravines and depressions. The compara- 

 tively light and evenly distributed snow covering in 

 the forest melts rapidly and runs off into the valleys 

 early in spring ; the very deep snow masses filling 

 the ravines do not melt until late in summer, and 

 therefore supply a full stage of water long after the 

 spring freshet has run by. There is some truth in 

 this observation, but by no means as much as some 

 of those advancing it imagine. In the first place, 

 something depends on the character of the forest. 

 In localities where it is rather thin, the drifting and 

 filling of ravines is not by any means entirely pre- 

 vented. On the other hand, where it is very dense, 

 its own shade tends to retard the melting, in the same 

 manner as the depth of the snow does in the ravines. 

 Again, it must not be forgotten that much of the 

 melting snow does not run off on the surface, but 



