Concerning Site 5 



From these figures it is evident that : The volume of site I in pine 

 or spruce is less than the volume of site II of the old standard. 

 The intervals are no longer the same, in pine, not even approxi- 

 mately, and they no longer follow the regularly decreasing series. 

 The proportion between different sites is approximately main- 

 tained. Volume is still the main guide or standard. 



That Professor Schwappach felt the difficulty in using volume 

 as basis in classification of sites is clear from his statement in 

 "Die Kiefer," 1908, p. 45, where he discusses the derivation of the 

 yield tables. Freely translated it is: "The starting point is the 

 study and determination of the height curves of the main stand. 

 The height is the factor least influenced by treatment." Also: 

 "/ consider, therefore, the height, leaving out some abnormal cases, 

 as the best criterion of the site in the stands of middle age and older, 

 while the volume of the main stand is suited for this purpose if the 

 stand has been properly cared for and is in normal condition for a 

 long period." He then goes on to say that if the total volume 

 produced, i. e.,main stand and sum of all thinnings are known, 

 the volume answers very well as measure of site. 



On page 47 he publishes the following table of heights for pine on 

 different sites: 



Comparing these figures of height for the 120-year-old stand 

 with the relative figures given before, it would seem that Schwap- 

 pach used height primarily as measure of site. 



That these changes should have come both in yield tables and 

 site classification is not surprising, for the great changes in the 

 practice of thinnings alone fiilly accounts for them. Thinnings 

 have increased to the point where in a well regulated forest of pine 

 with normal yields the sum of the thinnings each year exceeds the 

 cut of ripe timber or final cut. 



Here, in the United States, the matter of site and site classifica- 

 tion is important. A "valuation survey" or forest survey covering 

 several townships of land and costing thousands of dollars should 

 certainly tell at least approximately what proportion of the land 

 is good, fair or poor forest land. 



