Biomass and net annual primary production regressions for Populusgrandidentata on three sites in northern lower Michigan

Abstract

Dimension analysis techniques were used in the harvest of 31 largetooth aspen (Populusgrandidentata Michx.) from three mature stands (55 ± 7 years) representing a wide range of soil quality and clonal variation among aspen in northern lower Michigan, U.S.A. Regression equations were derived to predict component biomass and net annual production from tree dbh. Evaluation by analysis of covariance indicated significant differences (P < 0.05) in regression models among the sites.Total aboveground biomass of P. grandidentata was 171 565, 128 765, and 38 530 kg/ha at the good, intermediate, and poor soil sites where largetooth aspen constituted 81.5, 79.0, and 48.3% of the stand basal area, respectively. Corresponding aboveground net annual production values were 11 038, 7259, and 2925 kg/ha. Component percentages of total biomass were generally similar among sites, except for leaves. Variations in production percentages showed a production per unit leaf weight gradient parallel to the site quality gradient (i.e., poor site production per unit leaf weight was 33% less than the good site value). The errors inherent in the substitution of regressions derived from data from other sites were examined. Total biomass estimates ranged from −27 to +40% of accepted values. Errors for individual components ranged from −33 to +51%. Total aboveground biomass estimates from regressions for the combined data from all sites were acceptable within a standard error of the mean on the good and intermediate sites and with an allowance of 19% error on the poor site.