RESEARCH ON SILVICUTRURAL CHARACTERISTICS OF MOIST TROPICAL CLOSED EVERGREEN FORESTS IN TAN PHU PROTECTION MANAGEMENT AREA, DONG NAI PROVINCE

Abstract

Moist tropical closed evergreen forests in Tan Phu protection management area are enormously
rich and diversified in their floristic composition. The most dominant speicies are belonging to the
families of Dipterocarpaceae, Euphorbiaceae, Fabaceae, Myrtaceae, Annonaceae, Tiliaceae… In
total, there were 71 species, 49 branchs, and 36 families that include five species in Vietnam Red
Book and forty specices on big tree, the medium tree is twenty two species and the small tree is nine
species. It has been established two type of dominant combination: (1) Irvingia malayana +
Dipterocarpus dyeri + Shorea roxburghii + Shorea guiso; (2) Lagerstroemia calyculata +
Dipterocarpus alatus + Diospyros variegata + Dipterocarpus dyeri + Irvingia malayana. A large
number of tree around two kind of good and medium quality. The vertical structure of the forest is
distinguished in three stories, the highest stem and species number per ha are to be found in the
midldle storey with a percentage of 66%, following that in the lower storey with a percentage of
20% and in the upper storey with a percentage of 14%. The line of plot which is left-side slope,
coefficient value is from 21.8 to 23.8% and distribution of tree following tree’s dbh was a plot on
decrease by the forest have been restoring, the first dominantt combination were following Weibull
distribution anh another with Normal distribution. The canopy coverage in this area is 0.74 which
were establishing by David and Richards method and the number of generation seedlings are from
13639 to 18667 seedlings per hectare.