Spatial Structure of the Dominant Tree Species in an Evergreen Broadleaved Forest Stand in South Vietnam

The forest spatial structure yields important clues to understanding species interactions and the dynamics of forest communities. The present study was conducted at Dong Nai Cultural Nature Reserve, Dong Nai Province, South Vietnam, to understand the spatial structure characteristics of the forest stand and the dominant species in the evergreen broadleaved forest type. To collect data, we established a 4-ha study plot (200 m x 200 m) in the study area. All woody trees with dbh (diameter at breast height) >= 2.5 cm in the study plot were fully mapped and identified with their characteristics (species name, dbh, and height). Three research methods were the relationships of nearest neighbors, spatial point pattern analysis, and ISAR (individual species-area relationships) were used to analyze the spatial structure of tree species and their interactions. The study results showed that: (1) the tree species composition of the stand has a high mixture; the forest trees were uniformly distributed at the canopy layers of the forest and tended to be randomly distributed on the ground. (2) Spatial association of dominant species was mainly independent. (3) Interspecific interaction is the cause leading to the difference in the neighbor's diversity of dominant species. This study provides a theory for the management and spatial structure improvement of evergreen broadleaved forests in Vietnam from the achieved results.