Abstract:
Studies structure, compositions and successional trend of plant community by focusing on changing of species composition of tree, sapling and seedling in dry dipterocarp forest ecosystem, ecotonal ecosystem and mixed deciduous forest ecosystem in Huai Kha Khaeng wildlife sanctuary. The study used characteristic analysis for both physical structure and biological structure. The results show that in dry dipterocarp forest ecosystem Shorea obtusa Wall. and Shorea siamensis Miq. are the two dominant species in the structural composition in tree, sapling and seedling. In mixed deciduous forest ecosystem there are more and different dominants which are Terminalia nigrovernulosa Pierre ex Laness., Schleichera oleosa Merr., Lagerstroemia loudonii Teijsm. ex Binn., and Lagerstroemia duperreana Pierre. But the important value index of these dominant species are less than the dominants of dry dipterocarp forest ecosystem. In the ecotonal ecosystem.even though similarity of the dominant species is toward mixed deciduous forest ecosystem. But Shorea obtusa Wall. and Shorea siamensis Miq. are also presented with relatively high important value index. Species diversity index of the ecotonal ecosystem closes to mixed deciduous forest ecosystem. Therefore, these analyses suggest structure, compositions and successional trend of deciduous forest ecosystem in Huai Kha Khaeng wildlife sanctuary that the structure and compositions in the near future will be mixed between the dominant species of dry dipterocarp forest ecosystem and mixed deciduous forest ecosystem