SILVICUTURAL CHARACTERISTICS OF DIPTEROCARP FORESTS IN TAN PHU PROTECTIVE FOREST MANAGEMENT BOARD, DONG NAI PROVINCE

Abstract

This paper presents the tree species composition and structure of dipterocarp forests on red - yellow soil developed from granite and alluvial gray soil along La Nga river in Tan Phu Protective Forest Management Board of ​​Dong Nai province. The research data includes 16 standard plots with an area of ​​2,000 m². The research results showed that dipterocarp forests distributed on red - yellow soil developed from granite and alluvial gray soil along La Nga river. On red - yellow soil, Dipterocarpus dyeri was the dominant tree species, and Anisoptera costata was a co - dominant tree species. On the alluvial gray soil along La Nga river, Shorea roxburghii was the dominant timber species, and Dipterocarpus dyeri was the co - dominant timber species. The total number of tree species found in the dipterocarp forests was 57; of which the number of tree species found on red-yellow soil (49 species) was higher than on gray alluvial soil (37 species). The mixed index of dipterocarp forests on red - yellow soil (MI = 0.73) was higher than on gray soil (MI = 0.60). The N/D distribution of dipterocarp forests gradually decreases from small D class to large D class; of which 52.0% of trees were distributed at class D ≤ 10 cm, 43.0% at classes D = 16 ÷ 40 cm, and 5.0% at classes D ≥ 46 cm. The N/H distribution of dipterocarp forests has a left-skewed single - peak shape; of which 86.2% of trees were distributed at class H ≤ 16 m, and the remaining 13.8% at class H > 16 m.