CHAPTER IV 



FOREST DEVASTATION (Continued) 



" There is a serene and settled majesty in woodland scenery that 

 enters into the soul, and delights and elevates it, and fills it with 

 noble inclinations." WASHINGTON IRVING. 



NEXT to fire the greatest enemy of the forest is the in- 

 sect. If other forces did not intervene, insects would soon 

 multiply to such an extent that every green leaf would 

 disappear. In the constant struggle which goes on in both 

 the animal and vegetable life around us, these forces so 

 interact that any harmful increase of numbers of injurious 

 insects is checked by natural means. Storms destroy 

 and birds devour them. In northern climates winter re- 

 adjusts things, and a fresh start is made the following 

 spring, but the greatest regulating factors in their control 

 are food supply and disease. If the food supply is con- 

 sumed or destroyed, the increase must cease, while each 

 species has its insect or fungus parasite, which preys upon 

 it and lessens its numbers. 



Man often unwittingly disturbs this play of natural 

 forces. Sometimes, by his efforts, a certain food material 

 is very much increased, and the insects which live upon 

 that food increase accordingly until they become a pest, 

 finally destroying their own food plant and often swarming 

 to other plants where commonly they did not feed. . Some- 

 times, in his wandering, man introduces an insect to a new 



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