142 YEARBOOK OF THE DEPARTMENT OF AGRICULTURE. 



from the work of the next decade in that region. There are also other 

 districts in the semiarid region which have the same general conditions 

 and in which the Government still owns most of the land. It would 

 be a wise policy for it to establish reserves for forest planting in all 

 these sand-hill districts. The land is valuable for forest trees, and the 

 fact that settlers have passed over and around it for thirty years 

 without taking it up, shows that it is valuable for nothing else. 



Planting in these sections is an undertaking which logical!} 7 falls to 

 the General Government rather than to the State or the individual. 

 The investment extends over too. long a period for individual activity, 

 and besides the Government owns most of the land. The same reasons 

 exist, therefore, for the Government to undertake this work as for the 

 States to undertake planting in the White Pine belt. 



PLANTING IN THE WESTERN STATES. 



In the Western States, where the agricultural land is limited in area, 

 but highly developed through irrigation, forest planting will neces- 

 sarily be confined almost exclusively to the mountains. It is true that 

 in certain parts of southern California the profitable culture of the 

 Eucalypts for timber is being carried on even on very valuable agri- 

 cultural land. The climatic adaptations of this tree prevent its general 

 use, and no other tree grows rapidly enough in that region to pay on 

 valuable land. 



The necessity of a forest cover on the Western mountains is not now 

 doubted by an}"one who has studied the conditions at all deepl} T . Suc- 

 cessful irrigation depends upon a regular flow of water, which in the 

 Western States is dependent in an unusually high degree upon the 

 condition of the forest upon the mountains. A forest of good densit} T 

 acts in two ways both beneficial. It greatly lessens evaporation and 

 it diminishes the surface run-off, causing the water, instead of rushing 

 off the ground in surface torrents immediately following a rain, to 

 percolate gradually through the soil and to appear at lower levels in 

 the form of springs. 



It is often the case in the Western mountains that where the forest 

 is needed most it is totally lacking or else is too thin to exert any 

 appreciable influence on stream flow. This is true of very large por- 

 tions of the San Gabriel and San Bernardino Mountains, in southern 

 California, where by fire and grazing the forest has been entirely 

 destroyed. (PI. V, fig. 2.) Some of the best orange-producing and 

 lemon-producing land in the United States depends upon water from 

 these mountains for irrigation. With water it is worth from $1,500 to 

 $2,000 per acre, while beside it is land of exactly the same character 

 worth nothing, because there is no water available to irrigate it. 



The restoration of the forest on these denuded mountains would, 

 according to experience in similar countries, so increase the water 



