Comparison of biomass component equations for four species of northern coniferous tree seedlings

We compare equations predicting the biomass components (foliage, branches, stem, roots, total aboveground and total tree) for seedlings of four conife rous tree species: jack pine (Pinus banksiana Lamb.), red pine (Pinus resin osa Ait.), eastern white pine (Pinus strobus L.) and black spruce (Picea ma riana (Mill.) B.S.P.) grown under controlled experimental conditions for 3 years. Coefficients of determination (R-2) for the component equations exce eded 0.9 for jack and red pine, and ranged from 0.7 to 0.9 for white pine a nd black spruce. Basal diameter was the most important variable in all equa tions. Adding crown width improved the adjusted R-2 for total, aboveground, branch and foliage biomass equations by 2.5 %. Adding tree height improved the adjusted R-2 for stem biomass equations by 6.2 %. Root biomass equatio ns were not improved by including height or crown width. Using statistical comparisons of the full model (i.e. separate equations for each species) wi th three alternative reduced models that pooled various combinations of spe cies, we determined that none of the biomass component equations could be c ombined among the four conifer species. ((C) Inra/Elsevier, Paris.).