银瓶山自然保护区阔叶林冠层结构与辐射消减效应

为定量研究阔叶林群落的辐射消减效应，以银瓶山自然保护区常绿阔叶林为研究对象，设置2 hm²固定样地开展群落调查，并采用半球面影像技术获取冠层结构和林下光照指标，分析冠层结构对太阳辐射的消减作用。研究表明:样地林下光照（直射光、散射光和总光照）与林冠结构（叶面积指数、林冠开度）相关性极显著；林下直射光对林下总光照的贡献大于散射光，林冠结构与散射光的相关关系较直射光强；林冠结构与林木胸径有显著的相关性，而与林分密度的相关关系不显著；林冠对总光照的消减作用极显著，月际变化呈单峰分布，6月份消减量最大。

Canopy Structure and Radiation Attenuation Effects of Broad-leaved Forest in Yinpingshan National Nature Reserve

In order to quantitatively understand the radiation attenuation effect of evergreen broadleaved forest, a permanent plot with an area of 2 hm2 was selected in Yinpingshan National Nature Reserve to carry out the study. Hemispherical photographic technique was adopted to extract indices of canopy structure and understory light to further analyze the effects of radiation attenuation of the canopies. The main conclusions of this study were as following: understory lights (transmitted direct solar radiation, TDir, transmitted diffuse solar radiation, TDif, and transmitted total solar radiation, TTot) were significantly correlated and canopy structure (leaf area index and canopy openness). TDir provided a greater contribution to TTot than TDif, however canopy structure had a greater influence on TDif than TDir. Canopy structure was significantly correlated with diameter at breast height, and the correlation with tree density was not significant. Total radiation attenuation was highly significantly correlated with canopy structure. Monthly variation of attenuation effect showed a unimodal distribution, and reached the maximum in June.