Biomass from young hardwood stands on marginal lands: Allometric equations and sampling methods

The fixed-area plots method was successfully used to estimate relatively accurately oven-dry biomass per hectare. Results indicated that potentially harvestable woody biomass (oven dry basis) varied between 33-41 and 12-13 t ha−1 for the most and least productive marginal sites respectively. On the most productive site, LIS estimates (between 20 and 42 t ha−1) were usually lower than those obtained using different FAP sampling methods (i.e. systematic or random, small (50 m2) or large (100 m2) plots), but similar on the more open sites (between 10 and 14 t ha−1). Small FAP resulted in a plot without measurements in one case. Moreover, estimates based on small FAP were generally higher, even if not significantly different from larger plot estimates. We therefore suggest using FAP with 100 m2 plots to estimate small-diameter woody biomass on marginal lands with dense vegetation, while LIS, even if promising for open stands, needs further evaluation before recommendation.