Species Diversity of Trees in Dry Dipterocarp Forest at Sakaerat, Nakornratchasima I. Variations and Dynamics of Species diversity

Abstract

Study on variations and dynamics of species diversity of trees (DBH ≥ 4.5 cm) was carried out in 4 sub-types of dry dipterocarp forest at Sakaerat, Nakornratchasima Province. Variance analysis of Shannon-Wiener index’s H of the four stands and it’s relationship to other indices of species diversity, evenness and richness were studied and vompared to the dry evergreen forest in the same location and to the secondary and primary dry dipterocarp forests at Somdet, Kalasin Province. The study revealed that various indices were significantly correlated with H and enabling the indirect estimation of each index by using H as an independent variable. In the onset of study, it was found that the species diversity index (H) of the four stands were significantly different but H of Shorea floribunda-Quercus kerrii dominant stand was not significantly different from those in dry evergreen forest and primary dry dipterocarp forest at Somdet. H of stand dominated by Shorea obtusa-Pterocarpus macrocarpus was not different from the secondary dry dipterocarp forest. Monitoring of species diversity of Sakaerat dry dipterocarp forest for 9 years and dry evergreen forest for 11 years at Sakaerat and the primary and secondary dry dipterocarp forests at Somdet for 5 years suggested that Shorea obtuse-Pterocarpus macrocarpus dominant stand increased it’s species diversity significantly while other stand were positively or negatively changed more or less but not significantly observed.