Plant species composition and structure of the Mana Angetu moist montane forest, south-eastern Ethiopia
AbstractA floristic composition and structure study of the Mana Angetu Forest was carried out between July 2003 and June 2004 at four sites of the forest with an altitudinal range of 1533-2431 m. Three transects, 750 meters apart from each other, were established at each site from ridge top of the mountain to the bottom where human interference is low. A total of 81, 30 x 30 m quadrats were established at every 50 m altitudinal drop. For shrub and herbaceous layers 5 x 5 m and 2 x 2 m subplots were established
respectively, within the main quadrats. Data on species occurring cover abundance, diameter at breast height and numbers of individuals per species were collected from each quadrat. A total of 211 species belonging to 173 genera and 75 families were identified. Shrubs were represented by 33% of the species collected, followed by herbs (27%) and trees (23%). Seven clusters were recognized from the TWINSPAN output and the communities were named after 2 to 3 dominant species in each cluster.
The contribution of trees with DBH>2 cm for the total tree density was 49%,
whereas that of DBH>10 cm and 20 cm was 35% and 17%, respectively. The total basal area of the forest was 94m2/ha. Analysis of Importance Value Index indicated that Vepris dainellii had the highest value (79). The population structure showed that there is a need for conservation priority of species with poor regeneration. The presence of natural and anthropogenic factors affecting the forest causes concerns for its conservation and sustainable utilization.