SILVICULTURAL CHARACTERISTICS OF THE DIPTEROCARPACEAE DOMINATIONS IN THE TROPICAL SEMI-MOIST EVERGREEN CLOSED FOREST IN THE BINH CHAU - PHUOC BUU COASTAL AREA OF BA RIA - VUNG TAU PROVINCE

Abstract

This paper presented the results of research on the tree species composition and structure of Dipterocarpaceae dominations in tropical semi-moist evergreen closed forests in the coastal area of ​​Binh Chau - Phuoc Buu of Ba Ria - Vung Tau province. The collection data included five typical standard plots with a plot area of 2000 m². The research results showed that the number of tree species encountered in Dipterocarpaceae dominance was 56 species; including 6 species of Dipterocarpaceae (Shorea roxburghii, Dipterocarpus insularis, Anisoptera costata, Shorea siamensis, Vatica odorata, Hopea odorata). Dipterocarpaceae dominations had density, basal area, and wood volume at rich levels of 1576 trees/ha, 57.5m²/ha, and 443.9m³/ha, respectively. Dipterocarpaceae tree species contributed 60.4% in density, basal area, and wood volume, while the other 50 species contributed 39.6%. In the Dipterocarpaceae dominations, S. roxburghii was the dominant species, and D. insularis was the co-dominant species. The density of the stand decreased with increasing diameter at breast height at a rate of 6.2%. The height distribution (N/H) had a single peak; in which the highest tree number was concentrated at level H = 12m (46.1%). The Dipterocarpaceae dominations have a very high mixed index (MI = 0.75), the tree species were unevenly distributed in space (β – Whittaker = 1.94), and the tree species diversity index H’ = 2.69.