Some characteristics on tree species diversity of forest rehabilitation after shifting cultivation in Moc Chau district, Son La province

Abstract

Research was conducted to evaluate and compare tree species diversity of forest rehabilitation after shifting cultivation in Moc Chau dis trict, Son La province. A total of 50 temporary sample plots was established (each plot has an area of 400 m 2 (20  20 m)) and data was collected for all trees with total tree height ≥ 2 m and diameter at breast height ≥ 6 cm. The results showed that, with trees having H VN ≥ 2 m, the species diversity indices (including a number of species, Shannon-Wiener index, Simpson index) were highest at the forest rehabilitation after shifting cultivation 15 years (with the values of these indicators was 24, 2.810, 0.866, respectively) and the lowest at the forest rehabilitation after shifting cultivation 5 years (12; 2.162; 0.847, respectively); According to diversity profile, the intrinsic diversity at the forest rehabilitation after shifting cultivation 15 years is higher than that of the forest rehabilitation after shifting cultivation 10 years and 5 years. With trees having D1,3 ≥ 6 cm, the values of species diversity indices of the forest rehabilitation after shifting cultivation 10 years are 16 ; 2.184; 0.841, respectively, the forest rehabilitation after shifting cultivation 15 years increased to 21; 2.759; 0.879, respectively; According to the diversity profile, the intrinsic diversity of the forest rehabilitation after shifting cultivation 15 years is also greater than that of forest rehabilitation after shifting cultivation 10 years. In general, there is a difference in tree species diversity of trees with HVN ≥ 2 m and trees with diameter D1,3 ≥ 6 cm according to the rehabilitation time, the longer the rehabilitation time, the higher the species diversity level, but the tree species diversity level of the forest rehabilitation is still smaller than the natural forest (control).