Table 11. — Probability of a tree being unsound in 

 cubic foot volume — regression results 



Independent variables 

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



■ w ^--.r, J. J • : Number of 



Species, National Forest, and regression equations 



: trees 



White pine on Santa Fe, Carson, and Lincoln 



X^= -2.955536 + 0.05898932H 60 



-3.765521 + 0.05932042H + 0.6089821T 60 



Engelmann spruce on Santa Fe, Carson, and Lincoln 



X^= -1.655268 + 0.001678439DH 136 



X^= -2.931385 + 0.1798041D + 0.3704742T 136 



Corkbark fir on Santa Fe and Carson 



X(^= -2.994364 + 0.3277421D 35 



X^= -5.310682 + 0.3746394D + 1.414157T 35 



Yellow pine on Santa Fe and Carson 



X^= 0.9767974 + 0.03559618D 53 



Yellow pine on Lincoln, Coconino, and Tonto 



X(j = 0.3547862 + 0.003783644D 179 



Blackjack pine on Coconino 



X^ = -5.640547 + 0.04713862H 306 



= -6.206244 + 0.04502878H + 0.6055332T 306 



Blackjack pine on Lincoln 



X^ = -2.672635 + 0.05792241H • 57 



Blackjack pine on Tonto 



X^ = -4.768802 + 0.2093156D 380 



Blackjack pine on Santa Fe and Carson 



X^ = -1.418322 + 0.00006223427d2h 283 



X = -3.627838 + 0.1540565D + 0.6277967T 283 



c 



Douglas fir on Lincoln and Tonto 



X^ = -1.606318 + 0.0008139147DH 114 



Douglas-fir on Santa Fe and Carson 



X^ = -2.591351 + 0.1359878D 96 



X^ = -2.919862 + 0.001301024DH + 0.8573843T 96 



Aspen on Santa Fe and Carson 



= 1.202390 + 0.2220774D 146 



White fir on Lincoln 



X^ = -1.730640 + 0.1221281D 48 



White fir on Santa Fe and Carson 



Xe = -3.118569 + 0.04665243H 66 



17 



