554 JOURNAL OF FORESTRY 



area of the average acre of the stand (in square feet) by the height of 

 the average tree of the stand (in feet) and dividing by the average age 



cXh 



of the stand; or, in formula, site factor == •• Ihis works out 



n 



when appHed to Hanzlik's tables of Douglas fir about as follows: 



Site Factors 



Age Site I Site II Site III 



20 223 145 



60 470 355 79 



100 522 368 105 



140 518 353 127 



The advocates of this method claim that for the north Pacific Coast 

 region if the formula works out to over 400 that the site is good; that 

 when the result is between 300 and 400 the site is medium, and that 

 if the result falls below 300 the site is poor. 



It is noticed that in the above table the site at 140 years (under 

 Sites I and II) is slightly poorer than at 100 years. If now a stand of 

 timber is taken — hypothetical but not at all unusual in the Northwest — 

 about as follows : Basal area per acre, 400 square feet ; height of aver- 

 age tree, 250 feet; age of average tree, 350 years, then the site factor 

 per formula is 285 and the stand is classified as Site III, inasmuch as 

 285 is less than 300. If Site III in the Pacific Northwest supports trees 

 that are 250 feet tall, we shudder to think how the trees on Site I are 

 pestered by the clouds. It is evident that in this formula the site 

 varies with the age of the stand, for neither the basal area of the stand 

 nor the height of the trees increases in constant ratio with the age. 

 But, of course, site is not predicated upon the age of the stand it 

 supports. 



Medwiedew's method lacks in several other essentials. The basal 

 area per acre and the height of the trees practically determine the 

 volume per acre of the stand, and it is certain that the determination 

 of site by volume per acre cannot be used in broken stands. Again, if 

 the method were to be faithfully followed out it would be laborious 

 of application. 



Nor would the system be applicable to uneven-aged stands; for 

 what is the average height and age of the trees in an uneven-aged 

 stand? The method would be reduced to a basis of age on diameter 

 ^nd from diameters to heights ; and the question arises upon what site 



