THE FOREST AS A CONDITION. 57 



material, supply forests, there are other consid- 

 erations which enter into this problem of the eco- 

 nomic use of the soil and of distributing the various 

 conditions of its occupancy. These are based upon 

 knowledge of what we may call forest influences : 

 the influence which the existence of a forest cover 

 as a surface condition of the soil exerts upon soil 

 conditions, temperature conditions, and water con- 

 ditions, and by virtue of which we may charac- 

 terize them as protective forests. While the most 

 economic use of the soil for material production 

 necessitates relegation of forests to the poorer soils, 

 protective considerations necessitate its relegation 

 to certain localities. 



While our modern philosophy of nature readily per- 

 ceives that all things are interdependent, and hence 

 no change can take place in one condition without 

 corresponding changes in other conditions, even 

 the oldest civilized men intuitively recognized or at 

 least suspected and appreciated the fact that the 

 forest cover had some influence upon its surround- 

 ings, upon climate, health, and water conditions of 

 a country, as is evidenced by many sayings of 

 Mosaic, Roman, and Greek writers, by which far- 

 sighted priests prevented their destruction. The 

 consecration of groves to religious use and various 

 mythological conceptions connected with them, 

 point in this direction. 



Thus Homer calls the mountain woodlands the 

 habitations of the gods (re^evrj aOavdrow), in which 



