Height and Cubic-foot Volume Equations 



The lack of height-growth data necessitated developing alternative height equations for 

 assessing product potential as predicted by cubic-foot volume equations. Two separate 

 equations were developed for even-aged and for uneven-aged stands. 



EVEN-AGED HEIGHT EQUATION 



Minor (1964) developed an equation for even-aged blackjack stands in northern Arizona 

 that predicts heights of dominant trees as a function of site index and stand age. Plots of 

 average diameter class heights over diameter class size for the Taylor Woods height data 

 indicated that average diameter class height was below the height predicted by Minor's (1964) 

 equation for the smallest diameter classes and increased, asymptotically, to Minor's (1964) 

 height prediction in the largest diameter classes. Using the procedure outlined in appendix 

 H, the following equation was developed for use in even-aged, blackjack stands: 



D 1.35 



= ?IH - 0. 88015037 (MH-4. 5) (1.0 - —) 



u MU 



where 



Hp = average height of the Dth diameter class 



D = diameter class size 

 MH = maximum height as predicted by Minor's (1964) equation 

 = S - 1.4003 {/K - 10) + 0.1559(S)(/A - 10) 



S = Minor's (1964) site index 



A = breast height stand age, 20<A<^140 

 DM = maximum diameter class size that the stand has achieved in its development. 



UNEVEN-AGED HEIGHT EQUATION 



Because stand age is meaningless in uneven-aged stands, the foregoing even-aged equation 

 cannot be applied to uneven-aged stands. As an alternative, an equation that predicts average 

 diameter class height as a function of site index and diameter class size was developed using 

 the procedure described in appendix H. The equation is: 



(D+35)"2 



D 



where 



H. = bo ^ b^- S^2 . 



Hp - average height of the Dth diameter class 



D - diameter class site 



S - Minor's (1964) site index 

 bQ = 4.5 

 bi = 13.178649 

 b2 = 0.71631005 

 bj = -4221.6528 



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