Structural characteristics of natural forest place that Nghien (Burretiodendron hsienmu Chun et How) distribution in Dien Bien and Son La

Abstract

Nghien (Burretiodendron hsienmu Chun et How) is a large tree species, distributed and naturally growing in limestone karst areas below 1000m in Northern of Viet Nam and Guangxi province, Yunnan province, China. Merchus is a rare species of Group IIA of Decree 32/2006/ ND/CP of the Government of Vietnam and the UV group - will be endangered in the Vietnam Red Book 2007. In the structure of highland forest, In Son La and Dien Bien, Nghien belonged to the group of dominant ecological species and had the largest number of individuals compared with other species in the stand with IV% ranged from 13.86% to 36.62% and coefficient (Ki%) from 9.33% to 21.75%; The diameter of D1.3 is from 13.8 to 54 cm, the height of Hvn ranges from 8.6 to 22.6m. Species with the highest probability of occurrence are Shrimp (0.83) and Flowering
(0.77). The regeneration layer density ranges from 5,900 to 7,300 trees per hectare, with the potential regeneration of 73 to 88% of the regenerated trees in the stands, of which regeneration remains the dominant species. The composition of the coefficient (Ki) ranged from 6.06% to 36.36%