Table 3 — Definition of variables used in the Regeneration Establishment Model 



Variable 



Definition 



ASP Plot aspect converted to radians. 



SLO Plot slope tangent (slope percent/1 00). 



TIME Number of years since last disturbance to plot. 



REGT Number of years since last disturbance without budworm. 



BWAF Number of years since last disturbance with budworm. 



Note: REGT + BWAF = TIME 



BWB4 Number of budworm years in the 5 years before last disturbance. 



SQREGT Sum of square roots for each year without budworm. 



SQREGT = Z{(TIME^'2) - [(TIME-1 Y'^} for those years without budworm. 



Suppose there was no budworm in years 1 , 2, and 5. 



Then: 



YEAR= 1 2 3 4 5 



TIME^'^. [(TlME-1 y^)] = 1 .000 0.41 4 0.236 

 SQREGT = 1.000 + 0.414 + 0.236 = 1.650 



SQBWAF Sum of square roots for each year with budworm. 



SQBWAF = Z{(TIME^'2) _ [(TIME-I)^'^]} for those years with budworm. 

 Suppose there was budworm in years 3 and 4. Then: 



YEAR= 1 2 3 4 5 



TIME^'2- [(TIME-1 0.318 0.268 



SQBWAF = 0.318 + 0.268 = 0.586 



The effect of this variable is that budworm defoliation near the beginning 

 of the regeneration period will be more detrimental than defoliation near 

 the end of the regeneration period. 



Note: (SQREGT + SQBWAF)^ = TIME 



ELEV Stand elevation to the nearest 100 feet; for example, 35 = 3,500 feet. 



BAA Plot residual overstory basal area (ft^/acre), reset to 1 .0 if 0.0. 



NONE Class variable for no site preparation to the plot. 



MECH Class variable for mechanical disturbance to the plot. 



BURN Class variable for burn disturbance to the plot. 



ROAD Class variable for plots that occur on road cuts, road fills, or unmaintained 



roadbeds. 



PLANT Class variable for planted stands (probability of stocking equations and 



equations for determining the number of species on stocked plots) or the 

 stand planted to the same species being predicted (probability of species 

 occurrence equations). 



TPSP Number of regeneration-size trees on the plot, conditional on the plot 



being stocked with at least one established seedling. 



OVER Class variable for the presence of the same species in the variable radius plot. 



BOTTOM Class variable for bottom topographic position. 



LOWER Class variable for lower-slope topographic position. 



MIDSLOPE Class variable for midslope topographic position. 



UPPER Class variable for upper-slope topographic position. 



RIDGE Class variable for ridge topographic position. 



AGE Tree age at groundline. 



10 



