2 Plant Physiology 



decomposed to be termed soil, it indicates that something 

 is radically wrong with the soil or climate of that region 

 from the standpoint of the permanent occupation of it by 

 man or animal as well as by plants. 



Of all object lessons in permanent occupation by plants, 



FIG. 1. In the Rainier National Forest, Washington. [Photograph from 

 the Forest Service.] 



that of the aged forest stands out supreme. Here a vigor- 

 ous growth may have endured for centuries, and except 

 for such accidents as those of floods and fires, or of fla- 

 grant devastation by man, it might continue for centuries 

 more. So far as may be seen, or measured by the short 

 space of agricultural record, at least, there is with the 

 greater growth of the forest an ever increasing fertility of 

 the land. 



