Spatial distribution patterns of the dominant canopy dipterocarp species in a seasonal dry evergreen forest in western Thailand

Abstract

Population structure and spatial patterns were examined for four species of canopy dipterocarps (Anisoptera costata, Dipterocarpus alatus, Hopea odorata, Vatica cinerea) in a 50 ha plot in seasonal dry evergreen forest at the Huai Kha Khaeng Wildlife Sanctuary in western Thailand. Spatial dispersion was assessed with Morisita's index for quadrat sizes ranging from 61 m2 to 25 ha; spatial attraction and repulsion between species and size classes were measured with Iwao's index. Only Vatica had a negative exponential diameter distribution suggesting continuous recruitment. The other species had either normal (Hopea) or irregular diameter distributions with peaks in the large size classes (Anis..