Architectural analysis of relationship between biomass and basal area based on pipe model theory

To better understand and thus quantify an ecosystem function such as carbon sequestration and water relations, the biological implications of basal area (BA), which is one of the most convenient variables often used for the estimation of stem volume and aboveground biomass, are theoretically examined on the basis of pipe model theory. Quantitative analysis of profile diagrams leads to the formulation of plant architecture that simplistically describes the bifurcation manner in plant organs: i.e. the plant weight above a given position is in proportion to the stem cross-sectional area at that position. This simple linear relationship was shown to be applicable to the aboveground biomass estimation using BA in forest stands. Specifically, the linearity of the relationships between aboveground biomass and BA was validated for various forest stands. Pipe model theory, developed to describe tree architecture and forest profile, successfully explains the present relationships, and will contribute to the evaluation of forest ecosystem functions.