SPECIES DIVERSITY OF TREES IN DRY DIPTEROCARP FOREST AT SAKEARAT NAKORNRATCHASIMA PROVINCE III. TREE SPECIES DIVERSITY VARIATIONS AND SOIL FERTILITY

Abstract

Studies on the variations of tree species diversity in dry dipterocarp forest at Sakaerat resulting from soil fertility were investigated by using the results of discriminant analysis of soil and plant relationships in which soil fertility in forms of the accumulation down to 50 cm depth of soil organic matter and macronutrients were found to be effectively discriminated the similarity among the two groups of stands. The group of stands with low accumulation of soil organic matter but high calcium was found to be higher in number of tree species (S of DBH ≥ 4.5 cm), species diversity (Shannon-Wiener's H and Fisher's α ), maximum species diversity (H_max), evenness (E_l) and richness (R) indices as well as stand density (ρ) except for the concentration of dominance (C) than the group of stands with high accumulation of soil organic matter but low calcium. Soil fertility evaluated by the mentioned quantity was found to be non - significant determination factors for growth parameters measured in forms of mean stand diameter at breast height, mean height, mean total stand basal area and mean total aboveground biomass.