Abstract:

All free-standing trees within a 6-ha plot with diameter at breast height (DBH)≥1 cm were tagged, mapped, measured and identified to species. The spatial distribution patterns of four dominant canopy tree species in the plot were analyzed using a point pattern analysis Ripley’s L-function. A total of 12,131 free-standing individuals were recorded, including 68 species belonging to 49 genera and 25 families. Lithocarpus hancei had the highest basal area and the largest importance value. The second was Castanopsis wattii. Camellia forrestii, an understory tree species, ranked third in terms of importance value, although it showed the highest abundance (1,712 individuals). And this evergreen broad-leaved forest did not contain an obviously dominant species. The four dominant canopy species had a large number of seedlings and saplings and tended to be patchily distributed. We also examined the spatial distribution of 26 tree species with ≥40 individuals at each growth period (DBH ≥1 cm). Thirty-seven of 53 life history stages showed aggregated distribution pattern, suggesting that habitat heterogeneity may be more important than density dependence for regulating the population spatial structure of most tree species in the subtropical forest studied here.

Key words: tree species diversity, density dependence, habitat heterogeneity, aggregated distribution