TEE INANIMATE ENEMIES OF THE FOREST. 63 



all times to resist its growth, and even to sweep it 

 out of existence. 



The soil is continually undergoing a small 

 change in composition as the different growths of 

 plants appear and disappear. 



The earth's climate is at present undergoing but 

 very little change. In the geological past such 

 changes were so far-reaching and severe that they 

 were followed by pronounced changes in both the 

 animal and plant life. The comparatively small 

 changes that have occurred within historical time 

 are, perhaps, rather to be regarded as some of the 

 effects produced by the disappearance of certain 

 forms of plant life, than as the causes of such 

 disappearance. 



The exact balance of conditions that permit the 

 continued existence of forests is so delicate, that 

 causes, comparatively insignificant in themselves, 

 may finally produce marked effects. 



The enemies of the forest may be divided into 

 two classes : 



1. Inanimate. 



2. Animate. 



The principal inanimate enemies of the forest 

 are: 

 a. Fire. 



