THE FOREST AS A CONDITION. 71 



character of forest influences, which may change 

 their value. 



As far, then, as forest influence on climate is 

 concerned, we must admit that no satisfactory con- 

 clusions have been reached, excepting as to the 

 favorable wind-break effect. That wholesale forest 

 destruction and removal must change the climatic 

 conditions of the denuded area seems an entirely 

 reasonable assumption. 



The climatic influence of the forest upon its 

 neighborhood would finally consist in the commu- 

 nication of its own climatic characteristics; i.e. 

 shorter range of thermometrical extremes and more 

 even humidity, in general modifying extremes of 

 winter and summer. 



The influence on waterflow, although much fewer 

 attempts at exact determination have been made, 

 seems much more generally admitted. Here, too, 

 extravagant claims have been made as to the 

 efficacy of forest cover, while other factors which 

 influence waterflow have been often given less 

 consideration than they deserve. Thus the topog- 

 raphy and the geologic structure exert necessarily 

 a potent influence, which a forest cover may either 

 not be sufficient or else is not needed to modify. 

 VjThe philosophy of the influence on waterflow 

 rests mainly upon the recognition that the rain and 

 snow waters penetrate more readily a forest-cov- 

 ered soil than one that is bared of this protective 

 cover. The action here is of a threefold nature : 



