Spatial Biomass Variation, Biomass Dynamics and Species Diversity Relation to Topographic Factors of Lower Tropical Montane Forest

Abstract

Forest biomass and biomass dynamic was used in this study of forest structure and environmental assessment as one of the most importance criteria in order to understand forest ecosystem status and forest equilibrium. This research approached to evaluate the effects of topographic indices which including elevation, slope aspect, slope inclination and index of convexity (IC) on live tree aboveground biomass (AGB), biomass dynamic, and species diversity of 5 years inter-census intervals in a lower montane forest of 15-ha forest dynamic plot at Doi Inthanon. Spatial variation of biomass dynamic is drawn up by 20 x 20 m subplots (n=375) and then estimated biomass and biomass dynamics including AGB increment, AGB of ingrowth, AGB loss, and AGB change of each subplot. Differences in biomass, biomass dynamics, and species diversity among topography classes were analyzed by ANOVA. The results of this research revealed that the elevation had a significant effect on mean AGB, mean AGB of recruitment rate, and mean AGB of increment rate. Slope aspect shown a significant effect on mean AGB recruitment rate and mean AGB loss rate. Slope inclination had only a significant effect on AGB recruitment rate while IC had a significant effect on mean AGB recruitment rate and mean AGB of increment rate. Change in species diversity index  showed significantly different on topographic variables except slope aspect. The results suggest that the evaluation of forest biomass, biomass dynamics, and change in species diversity of the tropical lower montane forest should be based on data from various topographic sites. The relationship between mean AGB, biomass dynamic, species diversity and topography may mediated by difference in stand turnover rates, which must be relate to topography.

Keywords: forest biomass, forest dynamic, tropical lower montane forest, topography index,   species diversity