STRUCTURE AND REGENERATION CHARACTERISTICS OF (Gymnocladus angustifolius (Gagnep) J.E. Vidal) SPECIES IN TUYEN QUANG PROVINCE

Abstract

This study was implemented in Chiem Hoa and Na Hang district, Tuyen Quang province to determine some silvicultural characteristics of the species Gymnocladus angustifolius. The study used a method preliminary and detailed survey on 24 plots in two districts, with an area of each plot of 1000 m². Results showed that the species composition of woody tree species and regeneration was relatively similar structure, the species composition range was between 15 and 31 species. Dominant species involved in the forest composition of woody tree species, and the layer of regeneration were found in two classes (2 - 10 species and 2 - 12 species, respectively). The woody layer, Gymnocladus angustifolius, was presented in the seven plots, the regeneration tree species were found in two OTCs. The density of woody tree species, Gymnocladus angustifolius, recorded an average 395 trees/ha, the average density of Gymnocladus angustifolius species was 18 trees/ha. In contrast, the average density of regeneration was recorded around 2,723 trees/ha, the average density of regeneration Gymnocladus angustifolius species at two OTCs was 240 trees/ha. The rate of prospect regeneration seedlings was quite high about 62.18%. The seed regeneration species were found mainly between 0.5 and 1.5 m height, Gymnocladus angustifolius, and they randomly distributed in the forest with  <2 m height.