Plant Industries and Climatic Plant Formations 365 



James B. Berry 



Fig. 231. The pinon pine "protection" forest of the desert mountains of the Great Basin 

 region. The stand is very open but is of great value in preventing wind and water erosion. 

 In addition, it suppUes the ranchers of the adjacent valleys with fuel wood. 



Under proper supervision these grasslands are periodically grazed 

 by sheep, and the Forest Service receives a fee for the grazing 

 privilege. A third use made of forest reserves is the maintain- 

 ing of water supplies for irrigating purposes. In many of the 

 irrigated areas adjoining the mountains the rainfall on the moun- 

 tains is insufficient to maintain the streams throughout the grow- 

 ing season. The snowfall, however, is very considerable in the 

 mountains, and if the snow melts gradually it adds largely to 

 the available water at lower levels. When the forests are re- 

 moved, the snow melts rapidly and causes spring floods, which 

 not only waste the water but also cause erosion on the steep slopes 

 and destruction along the rivers at the bases of the mountains. 

 Where forests remain, the run-off is slower and the water more 

 evenly distributed. 



Forest reserves, therefore, are areas set aside by the govern- 

 ment to maintain a timber supply, to provide grazing lands, to 



