286 



THE FORESTER. 



December, 



reservoir during the eleven years of its ex- 

 istence has been about 5 per cent, of its 

 total capacity. The filling has been al- 

 most directly as the depth of the water, 

 being greatest at the dam, where the fine 

 mud is 2 to 2^ feet deep, and is largely 

 from the washings of plowed fields. 

 Were this reservoir higher in the moun- 

 tains the filling would be coarser and of 

 greater volume, and if the reservoir were 

 smaller, it would, of course, fill more 

 rapidly. 



Streams should always run clear, or 

 nearly so, and their volume should be uni- 

 form throughout the year. The more 

 perfectly the watersheds are covered with 

 forest growth, decayed leaves, chapparal, 

 and hardy grasses, the more nearly will 

 this ideal condition of run-off be ap- 

 proached. The soil will be so bound 

 with a network of roots that the rain and 

 melted snow will pass off slowly without 

 washing the surface, and the storage reser- 

 voirs will receive a minimum of detritus 

 and a maximum of water. 



This ideal condition, when perfectly at- 

 tained, becomes in fact a substitute in 

 large measure for storage reservoirs, and 

 the soil itself of the mountain forests is 

 converted into a great sponge, which con- 

 stantly replenishes the springs and streams 

 and keeps them in more uniform flow. 

 Under such perfect conditions, reservoirs 

 "would be needed only to store the water 

 of the rainy season for use in the Summer 

 months, while the streams themselves 

 would have higher irrigation duty in the 

 dry seasons. A general extension of for- 

 est growth will make available many small 

 reservoir sites that are now practically 

 worthless because of the torrential nature 

 of the streams, and their exposure to rapid 

 destruction. 



The essential, therefore, for the preser- 

 vation of storage reservoirs and the general 



o 



increase of stream flow is to maintain as 

 dense a growth of vegetation upon the 

 mountains as possible, and so patrol the 

 sources of our streams as to prevent the 

 spread of forest fires. 



It is not well established that forests have 

 any special influence in increasing the rain- 

 iall of a region, although the presumption 



is that they have a slight tendency in that 

 direction. But it is conceded that they 

 have a very decided influence upon the 

 temperature and humidity. In southern 

 California we particularly need all such 

 influence to counteract the effect of desert 

 winds upon our orchards, and lessen evap- 

 oration upon our reservoirs. 



The loss by evaporation in reservoirs, 

 ranging as it does from ten to fifty per cent, 

 of their capacity annually, according to 

 their relative depth and surface area ex- 

 posed, as well as their elevation above 

 sea level, is one of the most important fac- 

 tors in estimating the duty of stored water. 

 No other losses can compare with it, and 

 anything which will lessen it will extend 

 their usefulness. A general extension of 

 the forests of the arid region must have 

 marked effect in cooling the surrounding 

 atmosphere, reducing the velocity and tem- 

 perature of winds, increasing humidity, 

 and lessening evaporation. 



One of the encouraging features of the 

 situation on the Pacific Slope is the 

 rapidity with which all forest trees except 

 the Redwood are being reproduced 

 wherever they are protected from fires and 

 from the ravages of sheep. Young Pines, 

 Firs and Cedars spring up spontaneously 

 where there is soil and moisture, and grow 

 with vigor if let alone. This is in marked 

 contrast to the sand plains of Wisconsin, 

 Michigan and other more Eastern States, 

 where the Pine forests once out, seldom 

 reproduce themselves, but are replaced by 

 brambles and worthless brush. With 

 proper care, therefore, the Western forests 

 can be made a constant souixe of revenue, 

 continually replenished. 



A popular misconception of the intent 

 and object of the Government in segregat- 

 ing forest reserves at the headwaters of 







our streams, is that they are to be forever 

 left in a virgin state, and so lost to public 

 utility. This opinion is widely held, and 

 needs to be eradicated, for the reverse is 

 really true. 



The forests are not and should not be 

 regarded as too immaculate for use. It is 

 well recognized to be far better and safer 

 to make them a source of Iurifber and fire- 

 wood, utilizing the older trees and encour- 



