山西灵空山天然松栎混交林群落特征与冠层结构

以2011年建设的山西灵空山4 hm²天然松栎混交林森林动态监测样地为研究平台,以400个10 m×10 m样方为测量单元,于2016年进行群落特征研究,采用半球面影像法(DHP)分析冠层结构和林下光照特征.结果表明: 样地内共有乔木5558株,共计25种,分属于10科15属.冠层开阔度(CO)集中在15.0%～25.0%,叶面积指数(LAI)集中在1.5～2.5,林下光环境参数集中在10.0%～30.0%.建群种在样地内的分布对冠层结构和林下光环境影响显著;冠层结构对林下光环境所有参数的影响方向一致,其中采用叶面积指数评价冠层结构动态的效果更佳;冠层开阔度和叶面积指数对林下光环境产生相反的影响,且均对散射光入射率影响程度最大.温性松栎混交林的林冠层整体较为均匀,林下光分布较为集中,林分树种组成与冠层结构对林下光照影响显著.

Community characteristics and canopy structure of pine-oak forest at the Lingkong Mountain in Shanxi,China

We conducted a field investigation at 400 10 m×10 m quadrats in a 4-hm² plot of mixed forest dominated by pine (Pinus tabuliformis) and oak (Quercus wutaishanica), which was established in 2011 in the Lingkong Mountain of Shanxi Province, China. The community characteristics in the year of 2016 were analyzed. The digital hemisphere photograph (DHP) approach was employed to measure the canopy structure and the understory light parameters. The results showed that a total of 5558 individuals of trees of 25 species from 15 genera and 10 families were recorded. The canopy openness (CO) varied from 15.0% to 25.0%, the leaf area index (LAI) varied from 1.5 to 2.5, and the understory light parameters varied from 10.0% to 30.0%. The distribution of dominant species drove the canopy structure and the undergrowth light factors. The canopy structure defined the impacts of light factors in the forest. The leaf area index was more optimal in describing the canopy’s dynamic function. The canopy openness and leaf area index were negatively correlated to understory light availability, especially to the abundance of the incident rays of diffused light. Since the canopy structure was relatively uniform in the temperate pine-oak mixed forest, the understory light spots generally distributed in clusters. The tree species and canopy structure had significant effects on light environment in the forest.