Research on forest structure of Schima superba Gardn. Et Champ in central highlands

Vo Dai Hai, Nguyen Hoang Tiep

Forest Science Institute of Vietnam            

Schima superba Gardn. Et Champ is one of the large-sized, native, multi-purpose trees, often encountered in evergreen-broad-leaved forests that have undergone exploitation in provinces of the Central Highlands of Vietnam. This tree has been over used while our knowledge about it is rather little thus lacking in scientific bases for sustainable management of this tree species. Research results on natural forest structure of Schima superba is an important scientific basis for tending of rehabilitated and natural forest that have undergone selective felling.

Research is conducted in 5 provinces of Central highlands: Gia Lai,  Kon Tum,  Đak Nong, Dak Lak and Lam Dong. In each research point 3 temporary plots of 1000m2 in size are laid out. In the plot tree species, diameter, total height, crown diameter, forest density, forest cover of high tree layer and ground cover vegetation are recorded. Collected data are processed by statistical mathematics applied in forestry with Excel and SPSS software. Weibull, Mayer and spatial distribution functions are applied to model frequency structure law of D1,3 and Hvn. Correlation regression is used for modeling relationship between D1.3 and Hvn, functions with high correlation coefficient and low error are selected..

Research results shows that species composition of  Schima superba forest in Central highlands is rather diversified and rich with many tree species participated. However, there are only 3-8 major species participated in species composition structure (having species composition coefficient more than 0.5), remaining 7-55 species not participated officially in species composition structure (coefficient less than 0.5). Species composition coefficient of Schima superba varies from 0.1 to 3.4; IV index of Schima superba varies from 1.06 to 39.50%; Forest density varies from 266 to 994 trees/ha, density of Schima superba varies from 8 to 148 trees/ha; Mayer, weibull and spatial distribution functions can be used for modeling frequency structure law of D1,3 and Hvn. Result also shows that in rehabilitated forests and forests that have been undergone many times selective cutting, there are Schima superba trees existed with diameter at breath height more than 100cm but no so many, mainly existed in small diameter class less than 40cm.

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