A local basal area adjustment for crown width prediction
Nonlinear crown width regressive equations were developed for 24 species common to the upper Lake States of Michigan, Minnesota, and Wisconsin. Of the species surveyed, 15 produced statistically significant (P < 0.05) local basal area effect coefficients showing a reduction in crown width increasing stand density. No relation between shade tolerance and crown width was apparent, indicating the species-dependence of this parameter. Using adjusted R2 as a guide, nonlinear crown width models adapted for local basal area (NLCWadj) improved predictions for 20 of 24 species over a lacking this component (NLCW). The ecological significance of the improvement shown for some species may be minor, but for others the difference was substantial (often 8 percent).