XI 



SOME ENEMIES OF THE TBBES 



How small is the span of human life — ^three- 

 score years and ten — ^when compared with the 

 patriarchs among the trees ! A poplar tree, you 

 know, is hardly grown up till it reaches one hun- 

 dred and fifty years; a cypress may live five 

 hundred years or more ; some of the large red- 

 woods, "the big trees" of California, began life 

 long before Christ was born ! 

 ~~> A tree never dies of old age. Each year its 

 vital organs are renewed. The tiny cambium 

 cells are continually dividing and sub-dividing, 

 forming new tissues. The roots are reinforced 

 by the multiplication of the hair-like feeders, 

 which reach out farther and wider for food for 

 the tree's upbuilding. The annual renewal of 

 foliage puts into action new machinery and new 

 forces. Each year the tree increases in height 

 and in girth. Why, then, should it not live 

 forever? 



The answer is simple enough. The trees are 

 preyed upon by a host of natural enemies, and 



102 



