542 JOURNAL OF FORESTRY 



NOTES ON THE MEASUREMENTS OF THE VARIOUS SPECIES 



Michigan White Pine 



Michigan pines remain steadily for 160 years a little over one-third 

 the greatest height they could reach in still air on their stump diameter, 

 while this diameter changes from 11.3 inches to 31 inches and the height 

 from 63 to 138 feet. 



The curve showing the relation between height and stump-radius 

 of Michigan white pines for the 140 years noted here is the semi-cubical 

 parabola 



/z^=(21.6)V2 



where h is in feet and r in inches, or log (h) — ^ log (r)=log (21.6), 

 nearly. This gives a straight line when plotted in logarithms. 

 Also, log h-\og H = log (0.36). 



Pennsylvania White Pine 



Pennsylvania pines behave strikingly like the Michigan pines. 

 The\- are somewhat taller and larger than Michigan trees of the same 

 age. but their height relative to H is practically the same. Between 

 the 90th and 140th year they are relatively taller than Michigan trees. 



/t'=(21.8)V2 

 or,log (h)-}ilog (r)=log(21.8), 

 and log // — log H = \og (0.36) 



Average American White Pines 



Average value of h-r- -^ r"^ for 190 years is 21.7. We have for the 

 average of New England, Wisconsin, Michigan and Pennsylvania pines, 

 the same story as in the preceding cases, the trees showing, on the aver- 

 age, a little over one-third their still-air height, from the 40th to the 

 230th year. 



The World's Tallest White Pines 



The tallest white pine reported in Forest Service Bulletins is 200 

 feet high with a stump radius of 30 inches (Bulletin 22, p. 27). 



For this tree 



/? = 20.7V>^ 



3 



// = 59.4Vr2 

 .-. h = 0.2,SH 



And this tree has about the same relative height as Michigan and 

 Pennsylvania white pines. 



