348 JOURNAL OF FORESTRY 



Varia- 

 tion 

 in per cent —0.3 —0.4 —0.4 +0.3 +0.3 +0.6 —0.1 +1.0 



Formfactors according to formula 



ID^ + d* +d22 +d32 + + dg2 



10 D2 



.(Where D = ]0()) for red pine 0.439; for Scotch pine — 0.441. 

 Average age of the 11 trees is 41 years. 

 Average height, 45 feet. 

 Average d. b. h., 7.9 inches. 



Red Pine — Form Class /o.j — Average of 50 Trees. 

 Diam. at 



Absolute formfactors, red pine 0.480, Scotch pine 0.484. 

 Average age of trees is 41 years. 

 Average height, 48 feet. 

 Average d. b. h., 7 inches. 



Red Pine — Form Class /4.4 — -Average of 40 Trees. 

 Diam. at 

 sec. in per cent 

 of d. b.h. (b.h.) 

 Red pine 100 



Scotch pine 

 computed 



series 100 



Variation 

 in per cent 



Absolute formfactor, red pine 0.515 ; Scotch pine 0.524. 



Average age, 44 years. 



Average height, 48 feet. 



Average d. b. h., 6 inches. 



The difference in absolute form factors is of course due to the diverg- 

 ence between the red pine taper series and the mathematically com- 

 puted Scotch pine series in the top sections. Jonson's experience was 

 that his series derived from actual measurments nearly always fell 

 somewhat short of the mathematically computed series in the top sec- 

 tions. This, he believes to be due to the fact that the majority of the 

 trees examined by him were young or medium aged and had not yet 



