Simulation of a Simplified Coniferous Branch based on Radiosity Method

A simplified 3-D structure of coniferous tree canopy is used to replace the realistic but very complicated 3-D forest scene in order to study how the simplification method affects canopy reflectance. Results in this study show that it is feasible to model coniferous tree canopy scattering using simplified branch model (with no needles). With this approach, one can render coniferous forest stand in regional-scale so that radiosity-based model such as RGM can be used to study radiation regime in large-scale, 3-D, heterogeneous structures. Two kinds of conifer branches are simulated and compared: (1) coniferous branches with short needles; (2) equivalent part of "green" branches without needles. We used RGM (radiosity-graphics combined model) to calculate BRF (bidirectional reflectance factor) at visible and near infrared bands, and compared BRFs between conifer branches with and without needles. In most cases both agreed well.