44 graves: place of forestry among sciences 



Forestry as a natural science, therefore, deals with the forest 

 as a community in which the individual trees influence one an- 

 other and also influence the character and life of the cormnunity 

 itself. As a community the forest has individual character and 

 form. It has a definite life history; it grows, develops, matures, 

 and propagates itself. Its form, development and final total 

 product may be modified by external influences. By abuse it 

 may be greatly injured and the forest as a living entity may even 

 be destroyed. It responds equally to care and may be so molded 

 by skillful treatment as to produce a high quality of product, and 

 in greater amount and in a shorter time than if left to nature. 

 The life history of this forest community varies according to the 

 species composing it, the density of the stand, the manner in 

 which the trees of different ages are grouped, the climatic and 

 soil factors which afl'ect the vigor and growth of the individual 

 trees. The simplest form of a forest community is that composed 

 of trees of one species and all of the same age. When several 

 species and trees of different ages occupy the same ground, the 

 form is more complex, the crowns overlapping and the roots occu- 

 pying different layers of the soil. Thus, for instance, when the 

 ground is occupied with a mixed stand of Douglas fir and hemlock, 

 the former requiring more light, occupies the upper story, and 

 because of its deeper root system extends to the lower lying strata 

 of the soil. The hemlock, on the other hand, which is capable of 

 growing under shade, occupies the under story, and having shal- 

 low roots utilizes largely the top soil. 



These are forest communities, such for instance as those typical 

 of northwestern Idaho, where western larch, Douglas fir, western 

 white pine, white fir, western red cedar, and hemlock all grow 

 together. Such a forest is evidently a very complex organism, 

 the stability of which is based on a very nice adjustment be- 

 tween the different classes and groups occupying the same ground. 

 Any change in one of these classes or groups must necessarily 

 affect the other. If, for instance, in the Douglas fir-hemlock 

 forest, the Douglas fir is cut out, the remaining hemlock trees are 

 likely to die out because their shallow roots are left exposed to 

 the drying effect of the sun and wind. It is only by a thorough 



