Effects of stand structure on stem and crown biomass

Abstract

Above ground biomass can be divided in two broad classes, according to its potential use: stem biomass used mainly for timber; and crown biomass used either for bio energy or to maintain and improve ecosystem services, in particular stand and site sustainability and fertility. The aim of this study is to evaluate the differences and similarities of stem and crown biomass in forest stands as function of species, composition (pure vs mixed), structure (even-aged vs multiaged) and the stage of development (young vs adult). The analysis was carried out for eight species in 255 plots, in Portugal. The results revealed stem and crown biomass proportion depends on the tree species ecological characteristics, especially if trees are in free growth. Stem biomass proportion tends to be higher in stands managed for timber regardless composition or structure while crown biomass is higher in stands managed as agro forestry systems.