Diversity, Structure and Regeneration Status of Woody Species Along Altitudinal Gradient of Werganbula Forest at Sude District, Arsi Zone, Oromia Region, Ethiopia

Abstract

Abstract The study was conducted with objective to assess species composition, structure and regeneration status of woody species along altitudinal gradient of Werganbula forest at Sude District, Arsi Zone, Oromia Region, Ethiopia. The study area was stratified into lower, middle and upper altitudes. Nine transect lines at 500m interval were laid and nine sample plots were established along each transect line with interval of 200m. A total of 81 plots were established in the study area for vegetation data collection. For the collection of tree related data sample plots with 20m x 20m were laid along transect lines while for shrubs data five sub-plots of 5m x 5m were laid down, four at each corner and one at mid of each main plot. To collect saplings and seedlings data ten sample plots with 2m x 2m were laid down at two corners of each sub-plot. A total of 66 woody plants belonging to 43 families and 58 genera were identified from three altitudes of the forests. Fabaceae and Rosaceae were the most dominant families followed by Asteraceae and Araliaceae families. Out of recorded woody species, five (7.58%) were endemic to Ethiopia. The diversity of woody species in lower, middle and upper altitude were 3.35, 3.26 and 3.21 respectively. The overall density of woody plants species in the study area were 1012.35individuals/ha. The majority of the woody species in the study area were distributed in the lower DBH classes. The total basal area of woody species with DBH ≥ 2.5cm was 32.07m2/ha. The density of seedlings was higher than density of sapling and adults and of sapling was greater than adult at three altitudes. This result showed that, there were good regeneration and recruitment potential woody species at three altitudes of the forest. However, the population structure and regeneration status of some woody species in the study area were showed poor regeneration status which need priority conservation in order to ensure the sustainable utilization of the forest resource.