52 graves: place of forestry among sciences 



definite laws of forest distribution. The forests in the different 

 regions of the country have been divided into natural types with 

 corresponding types of climate and site. These natural forest 

 types, which, by the way, were also developed long before the 

 modern conception of plant formations came to light, have been 

 laid at the foundation of nearly all of the practical work in the 

 woods. A forest type became the silvicultural unit which has 

 the same physical conditions of growth throughout and therefore 

 requires the same method of treatment. The manner of growth 

 and the method of natural regeneration, once developed for a 

 forest type, hold true for the same type, no matter where it occurs. 

 After the relation between a certain natural type of forest and the 

 climate and topography of a region has been established, the 

 forest growth becomes the living expression of the climatic and 

 physical factors of the locality. Similarly, with a given type of 

 climate and locality it is possible for the forester to conceive the 

 type of forest which would grow there naturally. The forester, 

 therefore, may speak of the climate of the beech forest, of the 

 Engelmann spruce forest, of the yellow pine forest. Thus, if in 

 China, which may lack weather observations, we find a beech 

 forest similar to one found in northern New York, we can be 

 fairly certain of the climatic similarities of the two regions. More 

 than that, a type of virgin forest growth may serve as a better 

 indication of the clunate of a particular locality than meteoro- 

 logical records covering a short nmnber of years. A forest which 

 has grown on the same ground for many generations is the result 

 not of any exceptional climatic cycle, but is the product of the 

 average climatic conditions that have prevailed in that region 

 for a long time. It expresses not only the result of one single 

 climatic factor, but is the product of all the climatic and physical 

 factors together. Similarly, the use of the natural forest types 

 for determining the potential capacity of the land occupied by 

 them for different purposes is becoming more and more appre- 

 ciated. When the climatic characteristics of a certain type of 

 forest, for instance those of Engelmann spruce in the Rocky 

 Mountains, is thoroughly established, the potential capacity of 

 the land occupied by it for agriculture, grazing, or other purposes 

 is also largely determined. 



