INLAND DOUGLAS-FIR 



Site Index 



A site index equation, similar to the one given for Engelmann spruce, has been 

 derived for inland Douglas-fir by Brickell (3). The equation is: 



18 - 

 S = H . Z b.X., 

 ^=l 



where 



S = site index at a 50-year base age 



H = total height of a sample tree in the dominant stand 



and 



A = 



total age of a sample tree 







bi = 



40.984664 



Xi = 



1 



(A-1/2 _ 30-1/2^ 



bo = 



4521. 1527 



Xo = 



(A-2-^- 50-'-') 



bo = 







123059. 38 



Xo = 



o 



(A"3'5- 50"3*5) 



bu = 



-0. 5332868X10 ~S 



Xu = 



(A'+ - 50^*) 







Y — 



r A 5 cn 5~\ 



(_n - ou J 



5 



216.64152 



Xc = 



6 



H(A"^'^- 50"'^'^) 



by = 



-158121 . 49 



Xy = 



H(A^ - 50^) 



be = 



1894030.8 



Xb = 



H(A-5 - 50-5) 



bg = 



-0. 10230592X10-9 



X9 = 



HCA'^ - 50*+) 



bio= 



-6.0686119 



^10 = 



h2(A-2 - 50-2) 



bii = 



-25351.090 



Xh = 



h2(A-5 - 50-5) 



bi2= 



0.33512858X10-'+ 



Xi2 = 



h2(A - 50) 



bi3= 



0. 17024711X10-2 



Xl3 = 



h3(A-1 - 50-1) 



bi4= 



398.36720 



Xl4= 



h3(A-5 - 50'5) 



bl5= 



-0.88665409X10-8 



Xl5= 



h3(A^'5 - 50^'^) 



bl6 = 



0.40019102X10-1'+ 



Xl6 = 



h^ca'* - so"*) 



bl7= 



-0.46929245X10-8 



Xl7= 



h5(A-^/2 - 50-^/^ 



bl8= 



-0.16640659X10-20 



Xl8= 



h5(a'*-5 _ 50^-5). 



15 



