退化森林生态系统中林分碳储量的驱动因素——以内蒙古大兴安岭为例

目的]确定退化森林生态系统中林分碳储量的驱动因素,为其碳汇功能的恢复提供参考。方法]基于调查数据,使用逐步回归的方差分析法和结构方程模型(SEM)法,考虑林分因子和非生物环境因子(地形、气候),探究林分碳储量的驱动因素。结果]2种方法得到的结果基本一致:方差分析法的确定系数为0.890,林分因子中的平均胸径和株数密度,非生物环境中的月平均最高温和月平均最低温以及干扰类型对林分碳储量有显著影响;SEM中林分碳储量部分的模型确定系数为0.757,林分因子中的平均胸径和株数密度对林分碳储量的影响最大,其中株数密度既有正向的直接作用,也有负向的间接作用,而非生物环境中,月平均最高温对林分碳储量有间接的负向影响,各变量对林分碳储量的影响大小排序为平均胸径(0.94)>月平均最高温(-0.52)>株数密度(0.12)。结论]综合2种方法得到的结果,在退化森林生态系统中,林分因子和气候因子均对林分碳储量有影响,而地形因子却对其无显著影响。研究结果可为大兴安岭森林碳库探究提供数据参考和借鉴。

The Factors Affecting Carbon Storage in Degraded Forest Ecosystem:A Case Study from Daxing’anling Areas of Inner Mongolia

Objective] To determine the factors affecting carbon storage in degraded forest ecosystem and provide references for the restoration of carbon sink function. Method] Based on the survey data, and considering the stand factor and abiotic environmental factors(terrain factors and climatic factors), the variance analysis of stepwise regression and structural equation model method(SEM) were used to study the factors of carbon sequestration. Result]Two methods obtained basically consistent results: R^2 from the variance analysis method was 0.890. The average diameter at breast height(DBH) and tree number density among the stand characteristics, the monthly mean maximum temperature and monthly mean minimum temperature among the abiotic environment and the disturbance type had significant effects on the stand carbon storage. The stand carbon of R^2 derived from SEM was 0.757. For the stand characteristics, the average DBH and tree density affected the stand carbon the most. Tree density had directly positive and indirectly negative effects while among abiotic environment factors, the monthly mean maximum temperature had the indirectly negative effects on the carbon storage of stand. The impact of each variable on stand carbon followed the order of average DBH(0.94) > the monthly mean maximum high temperature(0.52) > tree density(0.12).Conclusion] Combining the results of the two methods, it is concluded that in the degraded forest ecosystems, both stand factors and climatic factors have significant impact on stand carbon storage while terrain factor has no significant impact. The results of this study could provide references for studying the carbon storage in Daxing’anling forest area.