Abstract

Litterfall in the forest is essential for balanced ecosystem processes. The present study determined seasonal variations of litterfall in the Boter-Becho forest, Southwestern Ethiopia. Based on forest disturbance level, two sites were selected: Low and high. Litterfall production in the high and low disturbed forest sites averaged 6.6 and 10.8 t ha^-1 year^-1, respectively. Significant differences (P<0.001) in litterfall were manifested between wet (0.6 ton ha^-1 month^-1) and dry (0.8 tons ha^-1 month^-1) seasons. Higher litterfall was associated with the dry compared with the wet season. Both litterfall and its fractions including leaf litter, reproductive parts and twigs followed a multimodal distribution pattern. Litterfall peaked during March, April, December, January and February with maximum peaks during March and December respectively. Monthly rainfall and temperature directly influenced litterfall production. Litterfall was strongly but negatively correlated with rainfall compared to ambient temperature. Although the present study provided useful information on the effects of low and high disturbance on litterfall production of the Boter Becho forest, further studies are required to quantify and understand the impact of disturbance on nutrient cycling specific to this forest.

Key words: Seasonal variation, site disturbance, leaf litter, reproductive parts, twigs.