Aboveground biomass and tree species diversity along altitudinal gradient in Central Highland, Vietnam

Aboveground biomass and tree species diversity along altitudinal gradient in Central Highland, Vietnam

Tran Van Do, Tamotsu Sato, Vo Dai Hai, Nguyen Toan Thang, Nguyen Trong Binh, Nguyen Huy Son, Dang Van Thuyet, Bui The Doi, Hoang Van Thang, Trieu Thai Hung, Tran Van Con, Osamu Kozan, Le Van Thanh & Ngo Van Cam

ABSTRACT

Central Highlands in Vietnam supports a very high forest cover and high tree species diversity. However, there are no quantitative studies that deal with altitudinal changes in aboveground biomass (AGB) and tree species diversity. Therefore, in this study we tested patterns of AGB, stem density, species diversity and canopy height along increasing altitude. A total of 49 temporary 50 m x 50 m plots were established in lower lowland (<500 m), upper lowland (500-1000 m), sub-montane (1000-1500 m), and montane (1500-1800 m) zones. All individuals having stem diameter at breast height (dbh) ≥ 10 cm were identified to species and measured for dbh. AGB (R2 = 0.67) and stem density (R2 = 0.39) significantly increased with increasing altitude, while top canopy height (R2 = 0.78) decreased. Species density (R2 = 0.52) and diversity Shannon-Weiner index (R2 = 0.31) significantly decreased towards higher altitude. Diameter at breast height showed a significant (R2</s = 0.26), but small, increase with increasing altitude. Cluster analysis indicated that there are two significant vegetation zones of different stand structures and tree species diversity in the Central Highlands of Vietnam, viz., lowland forests below 1000 m, and lower montane forests between 1000-1800 m elevation. This study found an increasing trends in AGB and stem density with increasing altitude.

Tropical Ecology, 2017 - Vol. 58 Issue 1, p95-104. 10p.