Fraction Cull in International 1/4-Inah Board Foot Volume Given the Tree Is Unsound — 

 Unforked and Forked Trees 



To predict the fraction of an unsound tree's International 1/4-inch board foot vol- 

 ume that is in cull, the following model is used: 



where 



Y 



FC. = 



FCj = h^ie ^) 



Predicted fraction cull in International 1/4-inch board foot volume to a 

 6-inch top given the tree is unsound 



A constant 



A function of the tree's attributes. 



The sp-NF specific values and functions of and Y^, respectively, the number of trees 

 used, and the resulting RMSQR values are found in table 15. The models for Engelmann 

 spruce and corkbark fir were too poor to be useful and, therefore, onlv their mean FC^ 

 values are included. Mean values of FC^ for the other sp-NF combinations are also 

 found in table 15. Methodological details can be found in appendix XIV. 



Table 15. — Fraation aull in International 1/4-inah board foot volume, 



given the tree i's unsound, data base, and regression results 



Independent variables 



D = D.b.h. in inches H = Total 



tree height in feet 







Species, National Forest, and regression results 



: Mean 

 : FC^ 



Number 

 of 

 trees 



Relative 

 mean squared 

 residual 



(RMSQR) 



White pine on Santa Fe , Carson, and Lincoln 









= 0.181977197 









= 9.53653005E-04(D'^) 



0.30592 



3S 



0.9776 



Engelmann spruce on Santa Fe , Carson, and Lincoln 









No model — Use mean FC^ 



.41094 



45 





Corkbark fir on Santa Fe and Carson 









No model — Use mean FC^. 



.55402 



21 





Yellow pine on Santa Fe , Carson, Lincoln, Coconino, and Tonto 









= 1.05452734 









= -1.89706097E-02(H) 



.28490 



202 



.9199 



Blackjack pine on Lincoln, Coconino, and Tonto 









= 0.420800123 









Y^ = -1.74436591E-02 (H) 



.15676 



138 



.9430 



Blackjack pine on Santa Fe and Carson 









= 0.467888236 









Y^ = -1.89407426E-01 (H/D) 



.22145 



114 



.9992 



Douglas-fir on Santa Fe, Carson, Lincoln, and Tonto 









= 0.839814911 









Yj. = -2.92010520E-01(H/D) 



.26258 



116 



.9479 



Aspen on Santa Fe and Carson 









= 1.39801055 









Yj = -a.79518535E-03 (H) 



.89429 



114 



.9364 



White fir on Santa Fe , Carson, and Lincoln 









= 0.251235533 









Y^ = 5.01411097E-06(D'H) 



. 34497 



62 



.9972 



24 



