Abstract:

Aims To ultimately understand of the mechanisms of species coexistence, the Chinese Academy of Sciences, in collaboration with the Center for Tropical Forest Science (CTFS) of the Smithsonian Tropical Research Institute, has recently initiated an ambitious large-scale, long-term forest dynamics and diversity plots network. Following the protocols of the CTFS forest dynamism plots, the China Network has been designed to establish four 20-25 hm² plots along the latitudinal gradient from North to South China. The Changbaishan plot (the CBS plot), the northern most plot of the China Network, is established for the benefit of understanding temperate forest ecosystem. This paper aims to address the community composition and structure of the CBS plot, serving as baseline information accessible for a wide range of future studies.
Methods Following the field protocol of the 50 hm² plot in Barro Colorado Island in Panama, a 25 hm² broad-leaved Korean pine mixed forest permanent plot of 500 m × 500 m was established in the summer of 2004 in Changbaishan. All free-standing individuals with DBH (diameter at breast height) ≥1 cm were tagged, mapped and identified to species.
Important findings There are 38 902 genotype individuals (59 121 individuals with branch), belonging to 52 species, 32 genera and 18 families. Floristic characteristics of the community belong to Changbaishan plant flora, including some tertiary relic species and subtropical species. Three species comprise 52.5% of all individuals, and 14 species comprise 95.2% of all individuals, while other 38 species comprise fewer than 5% of all individuals. The statistics of species
abundance, basal area, mean DBH, and important value showed that there are obviously dominant species in the community. The size-class structure of main species in the overstory layer showed nearly normal or bimodal distribution, while the species in the midstory and understory layers showed invert “J" distribution, even “L" distribution. Spatial distribution patterns of the main species, Pinus koraiensis, Tilia amurensis, Quercus mongolica, Fraxinus mandshurica, Acer mono and Ulmus japonica, changed differently with size-class and scales. Meanwhile, spatial patterns of some other species also showed spatial heterogeneity.

Key words: community dynamics, spatial pattern, biodiversity, broad-leaved Korean pine (Pinus koraiensis) mixed forest, Changbaishan