Stand Structural Diversity Drives Ecosystem Productivity in Subtropical Forests

The research was conducted in Liangping District, Chongqing, China (30°25′–30°53′ N, 107°24′–108°05′ E), covering a total area of 1,888.79 km². This region, known as a biodiversity hotspot, experiences a climate of subtropical monsoon with distinct seasons and abundant rainfall. Topographically, the area is characterized by heterogeneous landscapes, including mountains, ridges, troughs, and basins, as well as undulating hills. The forest coverage rate accounts for 66.60% of the territorial area; thus, this region is a representative area for national ecological protection and restoration, as well as a hot spot for biodiversity research. Ninety plots were chosen for the study site.