64 A PRIMER OF FORESTRY. 



The forest whicli we saw first in the seed lias now 

 passed through all the more vigorous and active stages 

 of its life. The trees have become standards and vet- 

 erans, and large enough to be valuable for lumber. 

 Rapid growth in height has long been at an end, diam- 

 eter growth is slow, and the forest as a whole is increas- 

 ing very little in volume as time goes on. The trees 

 are ripe for the harvest. 



Out of the manj^ things which might happen to our 

 mature forest we will only consider three. 



DEATH FROM WEAKNESS AND DECAY, 



In the first place, we will suppose that it stands un- 

 touched until, like the trees of the virgin forest, it meets 

 its death from weakness and decay. 



The trees of the mature primeval forest live on, if no 

 accidents intervene, almost at peace among themselves. 

 At length all conflict between them ends. The whole 

 power of each tree is strained in a new struggle against 

 death, until at last it fails. One by one the old trees 

 disappear. But long before they go, the forerunners of 

 a new generation have sprung up wherever light came 

 in between their isolated crowns. As the old trees 

 fall, with intervals, often of many years, between their 

 deaths, young growth of various ages rises to take their 

 place, and when the last of the old forest has vanished 

 there may be dift'erences of a hundred years among 

 the young trees which succeed it. (See PI. XXXII.) 

 An even-aged crop of considerable extent, such as we 

 have been considering, is not usual in the virgin forest, 

 where trees of very different ages grow side by side, 

 and when it does occur, the next generation is far less 

 uniform. The forest whose history has just been sketched 



