[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.