Branch and foliage mass and their vertical distribution in a 90-year-old chamaecyparis obtusa plantation

Abstract

In order to understand the dynamics of tree growth with increasing stand age, we developed models for estimating the foliage and branch mass and their vertical distribution, which influence tree growth, in a 90-year-old Chamaecyparis obtusa plantation in Hieizan Enryakuji Temple, Japan. We fit the expanded allometric equation to the relationship between distance from tree top and cumulative branch/ foliage biomass. We then obtained equations for estimating the parameters of the expanded allometric equation for each tree from its DBH and tree height. The vertical distribution of branch/foliage biomass in the crown was skewed downward for the small trees and upward for the large trees. Stand-level branch and foliage biomass were 18.3 and 9.6 t ha -1, respectively. Branch biomass culminated at 2.2 t ha-1 m-1 at 16 m above ground, while leaf biomass culminated at 1.2 t ha-1 m-1 at 17 m above ground. Together with previous studies, our results suggested that, in C. obtusa plantations, branch biomass culminated around 72 years and then decreased gradually, while foliage biomass was sustained. On the other hand, branch-to-foliage biomass ratio increased with stand age.