Kết cấu và đa dạng loài cây gỗ của rừng Dầu trên những loại đất khác nhau tại khu vực Nam Cát Tiên, tỉnh Đồng Nai

Abstract

This paper introduces some characteristics of Dipterocarp forests on different soil types in Nam Cat Tien area, Dong Nai province, Vietnam. The objective of the study was to determine the differences in tree species composition and tree species diversity of Dipterocarp forest on dark brown soil developed from basalt and yellowish red soil developed from clay rock. Tree species composition and diversity of Dipterocarp forests on each soil type was analyzed from three typical sample plots with the size of 0.25 ha. All trees with diameter at breast height (DBH) from 6 cm are listed according to species, DBH, height, basal area and volume. Then determine and compare tree species composition and diversity indicators of Dipterocarp forests on two soil types. Research results have shown that the number of tree species found in Dipterocarp forests on both soil types is 65 species belonging to 54 genera of 31 families; of which the number of families in Dipterocarp forests on dark brown soil (30 families) was more than that of yellowish red soil (25 families). Dipterocarpaceae family is the dominant ecological family; of which Dipterocarpus alatus is dominant species on dark brown soil, while Anisoptera costata is dominant species on yellowish red soil. The number of tree species found in Dipterocarp forests on dark brown soil (58 species) was higher than that of yellowish red soil (47 species). The similarity coefficient for tree species on these two types of soils is 76.2%. The mixed index of Dipterocarp forests on dark brown soil (0.21) was higher than that of yellowish red soil (0.17). The tree species diversity of Dipterocarp forests on soil dark brown soil is higher than the yellowish red soil. The number of precious tree species found on these two soils is 14 species. The number of rare tree species in Dipterocarp forests on dark brown soil (31 species) was higher than that of yellowish red soil (15 species).