樹木モデルを用いた植物個体光合成量の計算手法

Abstract

A method for computing photosynthesis rate of a tree using realistic plant models, AMAP, is discussed in this paper. Photosynthetic rate calculation is an important factor to estimate the growth rate of plants and landscape dynamics in green spaces. However, photosynthesis of plants is difficult to compute because of plants' complex three-dimensional structures composed of leaves, branches and trunks. Complicated structure makes it hard to quantify irradiation intensity caught by each leaf, which is a major factor to define photosynthetic rate. On another front, simulation models which recreate a plant structure inside computer make progress. This enables simulating light acquisition of leaves by ray-tracing methods. Accordingly we compute photosynthesis rate in a sunny summer day using AMAP plant models. The results show that photon weight for ray-tracing greatly influence the amount of photosynthesis rate, and should be set carefully according to target scale. And these calculations suggest that an impact of light shading by branches is slightly large. This method can be applied to a simulation of plants dynamics, for example. And such a simulation will be expected to offer new insights of the landscape managements.