Tropical forests have the largest potential to mitigate climate change amongst the world’s forests through conservation of existing carbon pools and expansion of carbon sinks. Ethiopia is one of the tropical countries which have significant forest resources carbon stock and their associations with environmental variables have not been well studied. This study was completed with the aim of assessing carbon stock variation along slope gradient and slope aspect gradient in Gedo forest. Data was collected from 10 m × 20 m plots along transects in systematically stratified forest section. The largest total mean carbon stock (570.67±40 ton ha-1) was found in lower slope class and the lowest total mean carbon stock (421.2±56.2 ton ha-1) was found in higher slope class. The deadwood biomass was only found in the lower slope class. The highest mean total carbon stock was calculated in east slope aspect (778.13±75.93 ton ha-1) and the lowest mean total carbon stock was calculated in south west slope aspect (358.58±73.45 ton ha-1). Slope has significant effect on leaf litter biomass carbon. Slope aspect has significant effect on aboveground biomass and below ground biomass carbon, soil organic carbon and total carbon stock. Based on the overall results, it is concluded that carbon stock in a forest ecosystem is determined by slope aspect and slope gradient.

Keywords: Biomass carbon, climate change mitigation, slope aspect, slope gradient, soil organic carbon