120 



water into the soil is made easier by the network of small roo^ • 

 and the channels left by the decay of large roots. Such is 

 beneficial influence of forests on run-off. 



INFLUENCE OF FORESTS ON CLIMATE. 



Other forest influences of a beneficial character exist but are 

 difficult to measure. The effects of forests on climate have been 

 studied in Europe and while ideas as to the elements which enter 

 into the problem have been cleared up, the real object of inquiry 

 has not yet been finally solved because methods of meteorological 

 inquiry and instruments are as yet unsatisfactory. For instance, 

 rain-gages may register amounts varying from 7 to 40 per cent 

 according to their construction and position and the character 

 of the wind and rain during the same storm. The problem is 

 too complicated for our present means to be settled by the 

 mathematical method. 



It has not yet been proven that forests produce rain. Because 

 of this inefficiency of mathematical measurements, we are thrown 

 back on the method of general observation in the field and the 

 conclusion has been that the tendency of a forest cover is to 

 reduce extremes of high and low temperatures and, on account 

 of its cooling effect, to keep the air within the forest and that 

 above it, nearer to the saturation point and as a consequence it 

 might occur that moisture bearing currents passing over would 

 precipitate their moisture more readily above or near the forest 

 growth. 



The forest, however, positively acts as a windbreak by break- 

 ing the velocity of dry winds and possibly enriching them some- 

 what with moisture and reducing the rate of evaporation over a 

 neighboring field. It also acts as a protection against cold winds. 



As far, then, as forest influence on climate is concerned, we 

 must admit that no satisfactory conclusions -have positively been 

 reached excepting as to this favorable wind-break effect. It is 

 reasonable to assume, however, that wholesale forest destruction 

 and removal must change the climatic conditions of the denuded 

 area. 



VALUE OF FOREST FOR RECREATION. 



There are other beneficial and indirect forest influences of 

 minor importance and one of these, which must not be overlook- 

 ed in our modern economy of city life, is "the recuperation of 

 bodily energy and of spirit which an occasional sojourn in the 

 cool, bracing, and inspiriting forest air brings to the weary 

 dweller of the city. This is an element in the general health con- 

 ditions of a people which must not be neglected." 



"From every point of view the forest is one of the most help- 

 ful friends of man and perhaps no other natural agent has done 

 so much for the human race and at the same time has been so 

 recklessly used." 



