SITE DETERMINATION, CLASSIFICATION, AND APPLICATION 553 



How vital these questions are is not realized until one begins to 

 collect and coordinate data on those species that range over wide areas. 

 How does the western yellow pine in Arizona compare to that in cen- 

 tral Oregon? How does the white pine in New Hampshire compare to 

 that in Minnesota? What is the relation between the growth of cotton- 

 wood on the river bottoms of Wisconsin and that in Missouri ? 



In many cases, even trees upon which a great deal of study and 

 investigation have been spent, it is utterly impossible to make satisfac- 

 tory comparisons of growth between two regions. The reasons for 

 this are not hard to find. 



The present lack of system in site classification and determination 

 is a jumble in several ways. In the first place, investigators differ as 

 to the classification of sites in a given locality making two, three, and 

 up to seven or more sites. Investigators differ also in the methods of 

 determination of site, for although one determines site by the volume 

 per acre of even-aged stands at a certain age, another uses as the 

 criterion the height of dominant trees at a certain age; still another 

 uses the chemical and mechanical qualities of the soil, while a fourth 

 measures site by a formula site factor which is founded upon the basal 

 area per acre, age of stand, and height of average tree. Finally, some 

 investigators apparently simply declare one site as good and another 

 as poor, and base yield tables accordingly. 



It is evident that the result can be nothing but the inevitable existing 

 confusion. It is, then, for us to determine a standard method of meas- 

 uring site ; and, having this determined, to scheme a frame upon which 

 sites may be classified for reference and relationship. 



TO DETERMINE A STANDARD MEASURE OF FOREST SITES 



A standard measure of forest sites should be a measure which is 

 sensitive to changes in site ; which is applicable equally to mixed and 

 to pure forests ; which is applicable equally to even-aged and to uneven- 

 aged stands ; which is applicable to any sized unit of area ; which is 

 simple and not laborious in application ; which is not affected by the 

 density of the stocking of the stand, and which is cosmopolitan in scope 

 With reference to these points, a few of the more common methods of 

 determining site are discussed. 



Medxvie dew's Method — On the north Pacific Coast a modificatioi 

 of the method of Medwiedew (a Russian forester) has been advocated 

 The method proposed is to obtain a site factor by multiplying the basa 



