8 Forestry Quarterly 



table (p. 21), in which again three sites are recognized. The 

 table gives only age and volume in board feet for the three sites, 

 leaving out height, diameter and even voltime in cubic feet corre- 

 sponding to these yields in board feet. The table begins with age 

 at 40 years. Chapman describes his method, plotting the results 

 of measurements of 85 tracts and drawing three curves, arbitrarily, 

 to represent the different values. 



For 120 years, probably a fair rotation here, the values run as 

 follows ; volume in board feet per acre as measure : 



Site Volume M. Feet B. M. Relative Values 



I 50.8 100 



II 36.7 72 



III 23.1 45 



If the heights as recorded, page 17, as maximum, average, and 

 minimum, are taken for 120 years, the values would be: actual 

 height, 104, 94, 78; relative: 100, 90, 75. 



Here we have a classification by volume into three classes with 

 a distinctly new set of limits. The bulletin does not give the 

 actual data, so it is impossible to judge to what extent the plots 

 really covered different classes of lands. This lack of real data 

 and the presentation only of averages and derived values is a 

 serious omission in much of our recent forestry publications and 

 is sure to militate against any general acceptance of the published 

 values. 



A very interesting table is presented by Chapman (p. 22, 

 table 13), where he attempts to work out a yield table based on the 

 nvunber of trees per acre and their size, the number being based 

 on the width of crowns as actually measured. The number of 

 trees at 200 years seems extraordinary and it would be interesting 

 to know if a stand of Norway pine has ever been calipered with a 

 basal area of over 300 square feet per acre as this table requires. 



The following brings together the few cases of site classification 

 mentioned, the figures being simply relative, site I taken at 100, 

 all but last column by volume. 



