Gross Scvihnev Board Foot Volume — Forked Trees 



The model for gross Scribner board foot volume to a 6-inch top for forked trees is 



where 



V„ ^ = Predicted gross Scribner board foot volume to a 6- inch top in a forked tree 

 > J" 



Vg = Predicted gross Scribner board foot volume to a 6-inch top in an unforked 

 tree, and 



Rg ^ = Predicted ratio of actual gross Scribner board foot volume to a 6-inch top 

 '•^ in a forked tree divided by predicted gross Scribner 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, Rc r., can be found in table 10. Methodological details can be found in appendix 

 IX. ^'^ 



Table lO. — Forked tree gross Scribner board foot volume to a 6-inch top 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 

 (RMSQR) 



White pine on Santa Fe , Carson, and Lincoln 



R ,= 6.69426337E-01 + 1 . 41693541E-02 (H) - 3 . 10631659E-02 (D) 

 S , J 



Engelmann spruce-cor)dDark fir on Santa Fe, Carson, and Lincoln 



R ^= 3.27406045E-01 + 9 . 24980748E+01 ( 1/D^ ) 

 S , J 



J- = -0.53128818 + 2.17203301E-02(D) - 1. 53128818 (P"^ ) + 3 . 06257636 (P) 



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

 Rg ^ = 1.16596696 - 2 . 01070651 (D/H) ^ 



Blackjack pine on Santa Fe and Carson 



Rg ^„ = 4.24761670E-01 + 1 . 23016529E-01 (H/D) 



""^R -= 6.97723772E-01 - 1 . 79745211E-02 (D) + 8. 11255589E-05 (H^ ) 

 '•' + 3.02276228E-01 (?) 



1.00494 



.98096 

 .98096 



14 



11 

 11 



.96266 31 



.86497 53 

 .86497 53 



0.5093 



.9191 

 .3868 



.7025 



.8029 

 .7426 



Blackjack pine on Lincoln, Coconino, and Tonto 

 R^ ^ = 1.50684356 - 1 . 94 318670 (D/H) 



""^R ^= 5.46618888E-01 + 1 . 15209503E-01 (H/D) - 1 . 75749455E-01 (T) 

 '•' - 4.53381112E-01 (p2) + 9 . 06762224E-01 (P ) 



1.00836 59 

 1.00836 59 



.8484 

 .7476 



Douglas-fir on Santa Fe , Carson, and Lincoln 

 R^ ^ = 6.39052346E-01 + 1 . 18994308 (H/D^ ) 



Aspen on Santa Fe and Carson 



Rg ^ = 4.03747500E-01 + 1 . 17109771E-01 (H/D) 



White fir on Santa Fe , Carson, and Lincoln 



R , = 6.31636481E-01 + 1 . 50605156E-02 (D) 

 S , J 



.99510 17 



1.01472 15 



.93862 12 



.6622 



.7935 



.7142 



14 



