Allometric relationships and carbon and nitrogen contents for three major tree species (Quercus crispula, Betula ermanii, and Abies sachalinensis) in northern Hokkaido, Japan.

Abstract

To evaluate the biomass of conifer-broadleaf mixed forests in northern Hokkaido, Japan, the relationships between tree dry masses (including belowground roots) and diameter at breast height (DBH) and tree height (H) for major three tree species (Quercus crispula Blume, Betula ermanii Cham., and Abies sachalinensis (F. Schmidt) Mast.) were calculated. In addition, carbon and nitrogen contents of each tree organ were measured for an accurate estimation of the carbon and nitrogen stocks in the trees. For all three species, one allometric equation explained the relationship between DBH (or DBH2 × H) and the dry masses of whole tree, aboveground total, trunk, branch, and coarse root. Leaf dry mass of Abies, a coniferous species, was higher than that of the two deciduous species at the same DBH. The allometric equations, except that for coniferous leaf, were comparable to previous studies in Hokkaido. The difference in the stand density is a likely reason for the large difference in the coniferous leaf dry mass between studies. Carbon and nitrogen contents for Abies were higher and lower, respectively, than the other two species for all organs (leaf, branch, trunk, and coarse root). Nearly all the measured carbon contents were less than but close to 0.5, and use of the constant value 0.5 caused 1-7% error in the carbon stock estimate of a tree.