白云山国家森林公园不同人为干扰强度的群落冠层结构和光照特征

为探究森林冠层结构与林下光照的变化规律及其相关性，在河南省白云山国家森林公园选取人工林、择伐林、皆伐林和老龄林建立四块面积为1 hm²（100 m×100 m）的固定监测样地，利用半球面影像技术获取冠层结构及林下光照数据。研究发现：1）随着人为干扰强度降低，冠层覆盖度与叶面积指数呈增加趋势，林下散射辐射与直接辐射呈减少趋势；2）择伐林冠层覆盖度与叶面积指数最大，平均叶倾角与透光比最小，林下光照（直接辐射、散射辐射）与冠层覆盖度和叶面积指数都呈显著负相关，林下散射辐射与冠层覆盖度和叶面积指数的负相关关系最强；3）处于不同干扰强度的群落由于冠层结构的差异，形成了不同群落内特定的光照环境。研究结果丰富了暖温带-亚热带生态过渡区森林冠层结构与林下光照动态变化研究资料，同时也为该区域森林的恢复与重建等提供科学的依据。

Canopy structure and illumination characteristics of different man-made interference communities in Baiyun Mountain National Forest Park

In order to explore the variation rule and correlation between forest canopy structure and understory light, four fixed monitoring sample plots with area of 1 hm² (100 m×100 m) were selected in Baiyun Mountain National Forest Park, Henan province, including Artificial forest, Twice-cut forest, Once-cut forest and Undisturbed forest in this study. The data of canopy structure and understory illumination were obtained by hemispherical imaging. Results show that 1) with the intensity of man-made interference decrease, the canopy coverage and leaf area index increased, while the scattered radiation and direct radiation decreased. 2) The canopy coverage and leaf area index of Twice-cut forest were the largest, but mean leaf angle and light transmittance were the smallest. The understory light (direct radiation and scattered radiation) were significantly negatively correlated with canopy coverage and leaf area index, while the understory scattered radiation had the strongest negative correlation with canopy coverage and leaf area index. 3) Because of the difference of canopy structure, the communities in different man-made interference stages formed specific illumination environment in different communities. The results of this study enrich the research data of forest canopy structure and understory illumination dynamics in the transition zone of warm temperate-subtropical transition region, and provide scientific basis for forest restoration and reconstruction in this region.