抚育采伐对针阔混交林林分结构及物种多样性的影响

Effects of tending felling on stand structure and species diversity of mixed coniferous and broadleaved forest

【目的】本研究以吉林蛟河天然次生针阔混交林为研究对象,研究抚育采伐对林分生长的影响,以期为吉林蛟河针阔混交林的可持续经营提供理论依据。【方法】研究采用了蓄积量和生物量分别作为生产力的指标,通过相关关系分析从3个物种多样性和5个林分结构指标中筛选出与生产力显著相关的变量,进而应用结构方程模型分析采伐对林分结构、物种多样性、生产力的影响以及林分结构、物种多样性和生产力之间的因果关系。【结果】在蓄积生产力的结构方程模型中,采伐对林分密度和林分结构有负影响,路径系数分别为-0.661、-0.216;采伐通过林分密度和林分结构间接作用于生产力,通过林分密度间接作用于物种丰富度。林分密度对物种丰富度、林分结构、生产力有正影响,路径系数分别为0.330、0.599、0.473。林分结构对生产力有正影响,路径系数为0.310。物种丰富度对林分结构有正影响,路径系数为0.414。物种丰富度影响林分结构间接作用于生产力。在生物量生产力的结构方程模型中,除林分结构对生产力无影响外,其他变量间的作用方式和蓄积生产力的模型相同。【结论】研究认为抚育采伐能直接或间接改变林分结构、物种多样性及生产力,而林分结构对生产力的作用比物种多样性大,因此森林经营管理中,在保护物种多样性的前提下,应注重对林分结构的优化和调整。

[Objective]In this study,the natural secondary coniferous and broadleaved mixed forests of Jiaohe in Jilin Province,northeastern China were used as research objects to study the effects of tending and cutting on the growth of stand,in order to provide a theoretical basis for the sustainable management of Jiaohe mixed forest of coniferous and broadleaved forests in Jilin Province.[Method]The study used volume and biomass as the indicators of productivity respectively,through the correlation analysis,the variables related to productivity were selected from the three species diversity and the five forest structure indexes,and then the structural equation model was used to analyze the harvesting for stand structure,species diversity,productivity impacts,and causal relationships between forest structure,species diversity,and productivity.[Result]In the structural equation model of accumulation productivity,harvesting has a negative impact on stand density and stand structure,with path coefficients of-0.661 and-0.216,respectively;harvesting indirectly affected productivity through stand density and stand structure,and indirectly affected species richness through stand density.The stand density had a positive impact on species richness,stand structure and productivity,and the path coefficients were 0.330,0.599 and 0.473,respectively.The stand structure had a positive impact on productivity with a path coefficient of 0.310.Species richness had a positive impact on the stand structure,with a path coefficient of 0.414.Species richness affected stand structure and indirectly affected productivity.In the structural equation model of biomass productivity,except for the stand structure had no effect on productivity,the mode of action between other variables was the same as the model of accumulation productivity.[Conclusion]The study suggests that tending can directly or indirectly change the stand structure,species diversity and productivity,while the stand structure has a greater impact on productivity than species diversity.Therefore,in forest management,under the premise of protecting species diversity,attention should be paid to the optimization and adjustment of the stand structure.