OUR FOREST RESERVATIONS. 127 



a large measure the reservations of these regions and the preservation of 

 their forest cover that give such great value to the adjacent cultivated 

 lields. It is the water and not the land that has value. It is the per- 

 ennial supply, flowing from the reserved and unreserved forests of 

 East and Central Arizona, that has in the past two decades rescued 

 the Salt River Valley from its former barrenness, with its scattered 

 growth of creosote brush and cacti, and transformed it into one of the 

 most fertile and productive areas in America. It is the forest cover 

 of the San Jacinto and San Barnardino reservations in Southern Cali- 

 fornia that gave Riverside and Redlands her splendid orange groves 

 and made possible the development of a productive and thriving 

 community. 



When in our Western forests one is constantly impressed by the 

 change in relative humidity wrought wherever the forest has been 

 removed. Springs have disappeared and caiions and ravines are now 

 dry, where there were formerly perennial streams. Under the leaf 

 mold and other debris of the forest, the soil is always moist, while on 

 denuded areas in the same locality it is parched and dry. Everywhere 

 the deep mulch forming the floor of the forest grasps the descending 

 rains and melting snows and guides them into the deeper recesses of 

 the earth. Where the forests have been destroyed, or even the mulch 

 and litter forming the forest floor, as it so often is by fire or the 

 excessive grazing of sheep, the rains for the most part, instead of 

 sinking into the soil, pass ovir the surface, carrying silt and other 

 debris into the streams and reservoirs, causing vital injury to irrigation 

 enterprises. 



So also in ' the semi-arid regions, where there are no forests, or 

 where they have been destroyed, the wind has a free sweep, resulting 

 in an enormous increase in evaporation. In some instances the evap- 

 oration from a water surface exposed to the free sweep of the wind 

 reaches a maximum of thirteen inches in a single month. In exposed 

 situations, snows a foot in depth are frequently lapped up in a single 

 day without even moistening the soil beneath. We do not appreciate 

 how great the necessity for the preservation of the forests is to the 

 irrigable West. 



Reservoirs for the purpose of impounding water to be used in 

 irrigation have been constructed by private enterprise in many parts 

 of the West, and the possibility of governmental construction of such 

 reservoirs is by no means improbable. Effective reservoirs are not 

 possible in our irrigable regions without due regard for the forests that 

 feed the streams which fill them. Forests everywhere are the great 

 preventors of erosion, and nowhere is this more evident than in our 

 Western mountains. The utility of reservoirs, and, to a lesser extent, 

 of distributing canals and laterals, becomes destroyed as they fill with 



