Table 14. — Probability of a tree being unsound in 

 board foot volume — regression results 



Independent variables 

 D = D.b.h. in inches H = total tree height in feet T = 1 + (number of forks) 

 S = 1.0 Tree with sweep or crook Pd = 1.0 Tree with porcupine damage 



0.0 Tree with no sweep or crook = 0.0 Tree with no porcupine damage 



: Number of 

 : trees 



Species, National Forest, and regression equations 



White pine on Santa Fe, Carson, and Lincoln 

 = -4.421720 + 0.1001612H 



Engelmann spruce on Santa Fe, Carson, and Lincoln 



or 



= -2.057921 + 0.1664132D 

 X = -2.412705 + 0.1689685D + 0.2973478T 



Corkbark fir on Santa Fe and Carson 

 X^ = -2.724328 + 0.3295897D 



Yellow pine on Santa Fe and Carson 

 X^ = 1.416597 + 0.08953296D 



Yellow pine on Lincoln, Coconino, and Tonto 



X = -0.3255527 + 0.09002528D 

 B 



Blackjack pine on Coconino 



Xg = -3.790069 + 0.002540676DH 



Blackjack pine on Lincoln 



X^ = -1.195571 + 0.03548680H 



B 



Blackjack pine on Tonto 



X_ = -4.866131 + 0.06649043H 



O 



Blackjack pine on Santa Fe and Carson 

 = -3.023414 + 0.05290037H 



= -3.551965 + 0.1806999D + 0.6451722T 



= -3.650835 + 0.06016044H + 1.278169(Pd) + 1,785158S 



Douglas fir on Lincoln and Tonto 



Xg = -4.201783 + 0.3419626D 



E)ouglas-fir on Santa Fe and Carson 



X = -1.185559 + 0.0O01857571d2h 

 i3 







or 









or 



^B 







or 



^B 









^B 



or 



X^ = -1.363273 + 0.0001709440d2h + 2.305584S 

 B 



Aspen on Santa Fe and Carson 



X = -3.889285 + 0.9000166D 

 B 



White fir on Lincoln 



X^ = -2.260617 



B 



White fir on Santa Fe and Carson 



X^ = -2.260617 + 0.05019542H 



X -2.955732 + 0.2320741D 



^B = -3.023744 + 0.2225154D + 1.260367S 



56 



103 

 103 

 31 



53 

 179 

 260 



49 



320 



271 

 271 

 271 

 271 



106 



84 

 84 



119 



45 



54 

 54 



23 



