Analysis of light climate under the canopy of a man-made forest in the tropics
Technical bulletin of the Tropical Agriculture Research Center
The light climate under the forest canopy was analyzed from the viewpoint of multistoried agroforestry systems. Illuminance under the tree crown was proportional to that in the open within a certain range, but it tended to be stable or rather to decrease with increasing illuminance in the open over this range. This phenomenon seemed to be due to the lack of differentiation between the direct and diffuse fractions of sunlight. Based on model experiments, only the diffuse fraction appears to affect directly the radiation under the shade, and the radiation climate could be analysed by two models simulating diffuse sunlight. The opening proportion in the canopy visualized by the hemispherical photographs was closely related to the diffuse radiation under the canopy. Solar radiation on the ground of Acacia auriculiformis A. CUNN. ex BENTH. stands was analysed by hemispherical photography and actual radiation measurements. The relationship between the stand structure and radiation reaching the ground for a given period could be formulated and diagrammatically illustrated based on the analysis. The results obtained for A. auriculiformis stands were compared with those obtained in preliminary studies of actual multistoried systems consisting of coconut palms and other agricultural crops.
|作成者||Yoichi Kanazawa Shozo Nakamura Robert V. Dalmacio|
|著者キーワード||light climate under the canopy multistoried agroforestry system direct radiation diffuse radiation|
|公開者||Tropical Agriculture Research Center|