Woody Species Diversity and Structure of Aba Sena Natural Forest, West Wollega Zone, Ethiopia

Abstract

Ecological study addressing species richness, diversity and vegetation structure is very important to produce data that could help conservationists to design a conservation strategy in the future. It was with this objective that the study was conducted on Aba Sena Natural Forest before it gets lost. Quadrats of 20m×20m (400 m²) were established at every 25 m elevation interval along five transect lines. Data on woody species richness, diversity, Diameter at breast Height (DBH) and Height were collected from 40 sampling quadrats. Species diversity was analyzed using Shannon-Wiener Diversity Index (H`). Importance value index (IVI) for woody species was determined by summing relative density, relative dominance and relative frequency. Hierarchical cluster analysis was carried out to determine plant community types. Overall, 69 woody species belonging to 67 genera and 36 families were identified. The overall Shannon-Wiener Diversity Index (H`) and the evenness values for the entire forest were 3.76 and 0.62, respectively. The most abundant woody species in their descending order were Ficus sur, Pouteria adolfriederici, Terminalia macroptera, Ficus vasta, Syzygium guineense and Albizia grandibracteata. The total basal area of the forest was 51.68 m² ha-1. Five plant community types with different number of vegetation quadrats were determined using cluster analysis. The current study did not include all aspects of the forest such as species regeneration status, anthropogenic impacts and ethnobotanical contribution of the forest for the local community and hence we recommend farther study on these and other aspects of the forest.