Altitudinal Changes in Species Diversity and Stand Structure of Tropical Forest, Vietnam
Tran Van Do *
Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan and Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Hanoi, Vietnam.
Osamu Kozan
Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan.
Tran Minh Tuan
Ba Vi National Park, Hanoi, Vietnam.
*Author to whom correspondence should be addressed.
Abstract
Ba Vi National Park (BNP) is known as one of the first parks established in Vietnam and has been well preserved against human disturbances. A study was conducted to understand altitudinal changes and aspect differences of species diversity and stand structure in evergreen broadleaf forest in BNP. Twenty plots (40 m x 50 m), distributing between 130 and 1,195 m above sea level were used for stem census, which were equally established in both eastern and western aspects. All stems with diameter at breast height (DBH) ≥ 10 cm were identified to species and measured for DBH. Results indicated significant linear relationships between elevation and basal area (G), top canopy height, species density, Shannon diversity index, and Evenness. Elevation zone of > 1,000 m above sea level had highest species density, Shannon diversity index, Evenness, stem density, G, and top canopy height, which were significant higher than that in 500-1,000 m and < 500 m elevational zones. Species composition in BNP was different between eastern aspect and western aspect, and both aspects shared 86 species in total 219 species found. While, stand structure and species diversity were not significant different between two aspects.
Keywords: Altitudinal zones, Ba Vi National Park, forest structure, tree species diversity, tropical forest