Concerning Site 13 



The first data of Schwappach's were gathered under a very differ- 

 ent thinning practice than the later ones, yet the relative heights 

 were not far different, being just two points higher in the less 

 severely thinned stands. But in comparing the heights and 

 volumes or the volumes in the two cases alone, the difference is 

 considerable, to the disadvantage of the older practice. 



Under the intensive thinning practice, the relative volume values 

 of the latter have been made almost equivalent to the relative 

 height values. 



Excepting those of columns 1 and 2, all the other values given 

 in the above table are for unmanaged forests, or for forests where 

 thinning practice has been only imperfectly or not at all developed. 

 The relative volume values for White pine show a less range than 

 those of Scotch pine for sites I, II and III. Is this not due to the 

 fact that, granting White pine site I is equivalent to Scotch pine 

 site I, White pine sites II and III are superior to Scotch pine sites 

 II and III in the ratios of 87: 79 and 72: 60 respectively? Had 

 the White pine sites been chosen so as to give volume values, say, 

 100, 79 and 60, instead of 100, 87 and 72, then the height values, 

 100, 96 and 91, proportionately reduced, would have been 

 approximately 100, 87 and 76, which figures show a striking 

 resemblance to those of Schwappach for height. 



The relative volume values for Loblolly pine in column 4 are 

 different from those given in the above article, in that they are 

 for peeled material. They are almost identical with those of 

 column 1, but the corresponding height values have a greater 

 than average range. This may be due to peculiarities of growth 

 and to the short age. 



The values in the last column are from Biilletin 308 of the 

 United States Department of Agriculture (Forest Service); they 

 show similar volume-height relations. 



These conclusions follow : 



1. Given normal stocking, a certain kind of tree, age and site 

 classification, there are definite relative voliime values for the 

 various sites, also definite corresponding relative height values. 



2. The intervals between pairs of consecutive height values are 

 less than those between corresponding volimie values. 



3. As a basis for site classification for normal stands not less 

 than middle-aged, we may use either volume or height. But, as 

 Professor Roth suggests, for abnormal stands the height is the 

 better indicator. 



