The nmemonics used in the subroutine are as follows: 



A = total stand age 



H = average height of trees in the dominant stand 



B = stand basal area per acre 



S150 = site index at a 50-year base age 



SD = stand density in percent as expressed by Lynch (7) , where 

 density is relative to the average for a 

 particular age and site index. That is, when 

 SD = 100 percent the stand is of average density; when 

 SD = 50 percent the stand is half average density, 

 and when SD = 200 percent twice average density is indicated. 



Average density of Lynch' s sample plots was a little less than normal for most ages and 

 sites. The extremes were 83.3 percent and 111 percent of what Meyer (8) called normal. 



Yield Capability 



The plot data used in Lynch 's study are the basis for the equation or procedure. 

 A regression equation was fitted to the relationship between age, site index, stand 

 density, and net cubic foot volume yield of the plots. When stands are assumed to be 

 of average density for the sample (SD = 1), the equation reduces to: 



In Y = bo+biln S-b2A-2 -b3ln S-b^ +(b5-b6)S-b7A-^S-^, . 



or 



Y = CqS^^ • exp (C2S - b2A-2 _ byA-^S'^), 



where 



Y 





net yield of 



all trees in cubic feet per acre 



S 





site index at 



a 50-year base age 



A 





stand age 





Co 





expCbo-bit) = 



13,100.281 



Cl 





bi - b3 = -0. 



4930327 



C2 





bs - bg = 0. 



26782874E-01^ 



b2 





467.59461 





by 





1843.6671 





then, mean annual increment = Y/A. 



2/ 



-^According to FORTRAN notation, E±n following a number means that the number is to 



be multiplied by lO^"'^-^. In this instance, the E-01 indicates that the decimal point 

 should be moved one place to the left (0.026782874). 



