Effect of leaf biomass and phenological structure of the canopy on plot growth in a deciduous hardwood forest in northern Japan

Abstract

We monitored leaf biomass, seasonal changes in leaffall, and plot growth for 11 years post-thinning in a secondary deciduous hardwood stand dominated by Betula maximowicziana Regel in central Hokkaido, Japan. Annual leaf biomass was divided into two phenological amounts: leaves that fell from May to September (early foliage) and leaves that fell from October to November (late foliage). Annual leaf biomass and the ratio of late foliage to annual leaf biomass changed with stand development, thinning, and insect outbreaks. Multiple regression analysis revealed that the gross growth rate was positively dependent on both early and late foliage, whereas the effect of early foliage was stronger than that of late foliage. This result indicates that plot growth was determined by not only total leaf biomass, but also the phenological structure of the canopy. In assessing and controlling forest productivity, the phenological structure of the canopy should be considered. © INRA, EDP Sciences, 2006.