Structural characteristics, quality and plant biodiversity in forest types at Xuan Son national park, Phu Tho province

Abstract

Forest structure plays a very important role in the sustainable management of forest resources. Research established 20 plots. The plot area is 900 m2 (30 m × 30 m) for 4 forest types: IIA, IIB, IIIA1 and IIIA3. Results showed that average diameter of four stages is IIA: 11.25 cm; IIB: 12.81 cm; II: 1: 15.94 cm and IIIA3: 20.30 cm. The mixed linear model demonstrated that growth in both diameter and height between forest states was significantly different (P < 0.05). Weibull and J-shape functions can simulate well for 75% of experimental distributions. Path analysis showed that for all four states, direct influence (AHTT) had a greater absolute value than the indirect effect (AHGT). Principal component analysis diagrams showed that for all four types, the quality of forest trees was closely related to canopy width, total height and diameter at breast height. The difference in the quality of the trees between the four states was really significant, as the Sig value of the Chi-square test is 0.000 (less than 0.05). Stages IIA and IIB had mainly species of pioneer species, while IIIA1 and IIIA3 had more shade tolerant species. Stage IIIA3 had the highest level of species diversity.