|
|
|
篇目详细内容 |
|
【篇名】 |
Dynamic emulation of the effect from a single tree to lower solar radiation distribution |
|
【刊名】 |
Frontiers of Forestry in China(Ceased publication after completion of Volume 4 (2009)) |
|
【刊名缩写】 |
Front. Forest. China |
|
【ISSN】 |
1673-3517 |
|
【EISSN】 |
1673-3630 |
|
【DOI】 |
10.1007/s11461-009-0039-x |
|
【出版社】 |
Higher Education Press and Springer-Verlag |
|
【出版年】 |
2009 |
|
【卷期】 |
4
卷3期 |
|
【页码】 |
297-303
页,共
7
页 |
|
【作者】 |
Bin FANG;
Qingke ZHU;
Wenhua LI;
Wei QIN;
|
|
【关键词】 |
protection forest; Populus tomentosa Carr; variation in shadows; solar radiation distribution; dynamic emulation |
【摘要】 |
|
By modeling the condition of light climate, we studied the negative effect of shadows in a shelterbelt forest. Based on the calculation of the apparent trajectory of solar motion according to an ellipsoid crown projection model and a Monsi light transmission model, radiation values of 36 experimental sites were measured using a light quantum meter. Estimates of daily solar radiation distribution from measured values were obtained. We built a crown projection model and simulated the conditions of a light climate in the forest. The trajectory of the shadow motion is shaped like a butterfly arc. The situation of the outside is affected by tree height (H) and that of the inner arc by height below the branches. In an area of 1.0 × H (toward the east and west of the tree) and 0.6 × H (toward the north), transmittance was below 90%, which means that the effect of shadow hazards occurs in this area. As well, the effect was strong at the bottom of the tree. The area of shadow hazards in the east and west of the tree was large and small in the south. The projection area of the shelterbelt forest was largest along an east and west direction. A certain distance between crops and the shelterbelt should be maintained when the shelterbelt is in a north-south direction. Therefore, the effect of shadow hazard will decrease north of the tropic of cancer. Cutting out the lower branches from the trees of the existing shelterbelt in a suitable and timely manner can reduce the area of the shadows. |
|
