为揭示不同间伐强度对冠层结构、林下光环境及林下植被生长和更新的影响,以红松针阔混交林为研究对象,利用Winscanopy 2010a冠层分析仪对中度、强度间伐及对照林分的冠层结构及光学特性进行测定,同时采用典型样地调查法,对林下灌木层和草本层的更新及多样性进行调查,分析间伐后林分的冠层结构及光环境特征,运用相关分析法对冠层结构和林下植被多样性的相关性进行分析.结果表明:间伐显著改变了红松针阔混交林的冠层结构,改善了林下光环境,与对照相比,中度(38%)、强度(48%)间伐林分的叶面积指数分别为对照的65.11%和71.7%,开阔度分别比对照增加205%和249%,林下总辐射分别为对照的2倍和5倍.冠层结构对林下光环境的影响较大,林冠开阔度与林下直射光、散射光和林下总辐射量呈极显著正相关(p<0.01),叶面积指数与林下散射光、林下总辐射呈极显著(p<0.01)和显著(p<0.05)负相关;间伐有利于林下阔叶树种更新,中、强度间伐林下幼苗的个体密度、基径、树高显著高于对照(p<0.05),且表现为随着间伐强度的增强而增强的趋势;林下光环境对林下植被多样性影响较大,灌木层的物种多样性指数与林下总辐射呈显著负相关(p<0.05),草本层多样性指数、丰富度指数与冠层开阔度呈显著正相关(p<0.05).间伐改善了红松针阔混交林的林下光环境,有利于林下阔叶树种的更新,对林下植被多样性具有较大的影响.%In order to reveal the effect of thinning intensity on the canopy structure, understory light environment and understory vegetation growth and regeneration, the canopy structure and optical properties for different thinning intensities of coniferous-broad leaved Korean pine mixed forest were determined by Winscanopy2010a. Their canopy structure and light environment characteristics after different thinning intensities were analyzed, and correlation analysis were used for analyzing the canopy structure and understory vegetation diversity as well. The results indicated that: 1) Thinning had significant effects on the forest canopy structure and light environment of understory. After thinning treatment at 38% and 48% intensities, the canopy leaf area index (LAI) was decreased to 65.11% and 71.7% respectively, compared to the control, while the openness was increased by 205% and 249%,respectively.Photosynthetic photon flux density was 2 and 5 times that of the control, respectively. 2)Understory light condition was greatly influenced by canopy structure. The canopy openness was highly significant positive correlated with understory direct PPFD, understory diffuse PPFD and total understory PPFD (p<0.01).The leaf area index was highly significant negative correlated with understory diffuse PPFD (p<0.01), significant negative correlated with total understory PPFD (p<0.05). 3) Thinning promote natural regeneration of broadleaf trees. After thinning treatment at 38% and 48% intensities, the individual density, DBH(diameter at breast height) and tree height were significantly higher than the control(p<0.05).4)Canopy structure had a greater influence on the diversity of undergrowth, shrub layer species diversity index was significant negative correlated with total understory photosynthetic photon flux density (PPFD) (p<0.05), the herb layer diversity index, richness were significant positive correlated with canopy openness (p<0.05). The understory light environment of Coniferous-broad Leaved Korean pine Mixed Forest has been improved after thinning. Thinning was beneficial to the regeneration of understory broad - leaved species, and had an obvious influence on the diversity of understory vegetation.
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