126 



AMERICAN FORESTRY 



HERE THE WOODLOT is BEING USED FOR GRAZING BUT THIS PREVENTS 

 REPRODUCTION, THE Cows DESTROYING THE YOUNG TREES 



munities. To be successful in forest 

 management, the practice must con- 

 form to the conditions and full advan- 

 tage must be taken of the factors of 

 growth which control in any given 

 situation. 



These factors fall into two great 

 iToups, not however, clearly denned. 

 These may be termed the "Natural" 

 factors, including only the broad fea- 

 tures closely related to climate, etc. 

 over which man has but little control, 

 and the "Subsequent" factors, brought 

 about mainly by man himself, or 

 through changes which he has wrought. 



Briefly, the great natural factors of 

 growth arc: Moisture, heat, light, soil, 

 slope, aspect and wind. 



Moisture is a most important factor 

 in tree growth. Without moisture trees 

 cannot grow. But different trees differ 



widely , in their demands for moisture, 

 and only those trees adapted to the 

 moisture conditions should be used in 

 a given situation. For instance, the 

 red pine can grow on very dry sites, 

 while the black ash must have moist 

 ones. 



However, it is the minimum amount 

 of moisture which any tree must have 

 that is most important. Up to a rather 

 high per cent, of moisture, such as in 

 permanently soggy ground or in swamps, 

 almost any tree can do better, the 

 greater the amount of moisture it has. 



Therefore, in forest management, it 

 is important not only to use species 

 adapted to the general moisture condi- 

 tion, but to use such practices as will 

 conserve and improve the moisture 

 factor. 



As a genreal proposition, the woods 



