Gross International 1/4-Inah Board foot Volume — Forked Trees 



The model for gross International 1/4-inch board foot volume to a 6-inch top for 

 forked trees is 



where 



I,/ 



Predicted gross International 1/4- inch board foot volume to a 6- inch top in 

 a forked tree 



Predicted gross International 1/4-inch board foot volume to a 6-inch top in 

 an unforked tree 



Predicted ratio of actual gross International 1/4-inch board foot volume to 

 a 6-inch top in a forked tree divided by predicted gross International 1/4- 

 inch board foot volume to a 6-inch top in an unforked tree. 



The appropriate equations for R. ^, their RMSQR, the number of trees used, and the mean, 

 ratio r., can be found in table 8. Methodological details can be found in appendix VII 



Tiible 8. — Forked tree gross International 1/4-inah board foot volume data base and regression results 



Independent variables 



D = D.b.h. in inches P = Height to first 



fork divided 



by H 





H = Total tree height in feet T = 1 + (number of 



forks) 







Species, National Forest, and regression equations 



: Mean : 



Number 

 of \ 

 trees 



Relative 

 mean squared 

 residual 

 (RMSpR) 



White pine on Santa Fe , Carson, and Lincoln 









Rj. ^ = 2.21682508E-01 + 5 . 95430677E-05 (H ^) + 2 . 299002 34 (H/D 2) 



1.16873 



17 



0.4462 



Engeimann spruce-corkbark fir on Santa Fe, Carson, and Lincoln 









Rj. J.- = 3.709O6603E-01 + 7 . 71762038E+01 (l/D^) 

 ""^R^ ^ = -.46864127 ■>■ 1 . 74260009 (H/D 2) + 1 . 46864127 (P) 



1.23734 



16 



.4278 



1.23734 



16 



.4154 



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









R^ - = 1.16393889 - 2 . 0394463 3 ( D/H ) ' 

 I ■ J 



.95773 



31 



.6744 



Blackjack pine on Lincoln, Coconino, and Tonto 









Rj. ^ = 5.49502730E-01 + 1 . 09541429E-01 (H/D) 



.99776 



62 



.8895 



""^R „= .61350474 + 9.60847876E-02 (H/D) - 1 . 52902459E-01 (T) 

 '•' + 7.72990514E-01 (P) - 3 . B6495257E-01 (P^) 



.99776 



62 



.8238 









Black-jack pine on Santa Fe and Carson 









^ = 4.15854140E-01 + 8 . 37338276E+01 (l/D^) 



1.03576 



63 



.7438 



Douglas-fir on Santa Fe , Carson, and Lincoln 









R^_^^= 5.38416406E.02<H-^-=°S''^°") 



2.12047 



20 



.7158 



Aspen on Santa Fe and Carson 









Rj ^ = 5. 13375186E-01 + 4 . 2072 5160E+01 ( l/D^ ) 



1.08110 



31 



.9188 



White fir on Santa Fe , Carson, and Lincoln 









R^ ^ = 6.81631222E-01 + 1 . 35O49045E-02 (D) 

 °^K^ f. = 3.05788475E-01 + 2 . 34 528327E-05 (H ^ ) + 6. 94211525E-01 (P) 



.95691 



12 



.7677 



.95691 



12 



.7643 



12 



