WESTERN WHITE PINE 



Site Index 



Site index for even-aged stands of western white pine can be estimated by the 

 equation : 



S = boH [1 - bi • exp (h2fy)]^^, where 



S - site index at a base age of 50 years 



H = average height of dominant and codominant trees 



A = age of the oldest dominant tree in the even-aged 'stand 



bo= 0.37504453 • ■ - ^ 



hi= 0.92503 



b2= -0.0207959 



b3= -2.4881068. 



This equation was obtained by fitting an equation of suitable form to the height/age 

 data in table 24 of Haig's (4) yield tables, then algebraically solving the latter 

 equation for site index. Written in FORTRAN IV (IBM 360) the equation is: 



S = 0.375045 * H * (1.0 -0.92503 * EXP (-0 . 020796*A) } ** (-2 .48811) . 



Figure 1. — Relationship between site index and yield capability. 



