鼎湖山季风常绿阔叶林林冠结构与冠层辐射研究

STUDY ON CANOPY STRUCTURE AND CANOPY RADIATION OF MONSOON EVERGREEN BROAD LEAF FOREST IN DINGHUSHAN BIOSPHERE RESERVE, GUANGDONG

本文研究了鼎湖山自然保区的亚热带季风常绿阔叶林的林冠结构与冠层辐射，结果表明：１．该群落的叶面和指数为１７，叶面积指数在水平方向的分布是均一的，但在垂直方向上则是非均匀的，整个群落对光能的截获率力９６．３％，其中最上层乔木截获了总入射光强的７８．２８％，下野乔木及灌草层只截获１７．８３％，但冠层辐射仍遵循消光定律。２．群落的叶倾角影呐冠层辐射，该群落冠层上部的叶倾角在４５°－７０°处具有最大分布频率，而中下层则在５°－３５°有最大分布频率。高的叶面积指数与时的直立性相关。３．该群落上层乔木枝下高较高，且中上部枝条与树干夹角较小，枝的着叶数较多且枝的着叶长度较长；而下层乔木和灌木枝下高较低，大部分枝条与树干夹角较大，且叶多着生于枝端。这种冠层格局由冠层辐射引起。４．该群落植物叶和枝条的取向在各方向上机会均等。５．群落的叶片从上到下变大，这种格局对森林的能量分配和水分平衡有重要意义。６．该季风常绿阔叶林以林冠为活动面，林冠上层呈多孔体，中下层郁团，对太阳辐射有较强的吸收能力，因而反射率较低，年均仅３．１５％。７．植物个体结构与群体结构不同，当一个有良好结构的个体处于密度较大的群体中，将会因适应坏境而改变个体生产?

The canopy structure and canopy radiation of a monsoon evergreen broad leaf forestis described at 7 aspects in Dinghushan biosphere reserve.The results show:1. The leaf area index of the community is 17. The vertical distribution of leaf area indexand canopy radiation decreases from top to bottom, and the radiation through the forestcanopy follows extinction law. 2. The main distribution range of leaf angles is 45°-70° in theupper layer of the canopy, 5°-35°in lower layer. So higher leaf area index is relative to standing position of leaf. 3. Canopy radiation influences branch angle, brance height and the leafdistribution pattern of branch. 4. Orientation of leaf and branch is random. 5. The leaf sizefrom top to bottom of community increases. This pattern benefits the forest productivity. 6.The top layer canopy is not continuous, but canopy in the centre is continuous. This structureis helpful to absorption of radiation, so the reflectivity is low with 3. 15 % annually. 7. The individual structure is different from community structure. Radiation environment can changethe individual structure, further influencing community productivity.