WOODY SPECIES COMPOSITION AND DIVERSITY IN VEGETATION OF TULU KORMA, WEST SHAWA, OROMIA, ETHIOPIA

Abstract

The study on Tulu Korma dry evergreen afromontane forest was conducted with the objectives of assessing its species diversity, dominance and regeneration status. Vegetation data were gathered from 52 quadrats of 20 m x 20 m (400 m2) laid systematically along 5 transects. In each quadrat, live woody species were recorded with their number counted and DBH measured for those with DBH>2.5cm. Voucher specimens of species were collected and identified in Haramaya University Herbarium using literatures and experts. Quantitative data such as Shannon-Weiner diversity index, eveness, density, basal area and important value index were computed. Species density was also seen against ten DBH classes 1) 2.5-10.0cm, 2) 10.01-20.0cm, 3) 20.01-30.0cm, 4) 30.01-40.0cm, 5) 40.01-50.0cm, 6) 50.01-60.0cm, 7) 60.01-70.0cm, 8) 70.01-80.0 cm, 9) 80.01-90.0cm and 10) 90.01-100.0cm to visualize regeneration status of the vegetation in the study area. Results show that A total of 132 woody vascular plants belonging to 99 genera and 49 families were identified. Fabaceae and Asteraceae are the dominant familes in terms of species richness. Overall average Shannon-Wiener diversity index (H`) was 3.44 and the average evenness values (E’) was 0.7 indicating high diversity with more or less even distribution. Furthermore, 9 endemic species many of which are under the Red Data List of IUCN were also identified. Woody species densities for mature individuals were 1608.04 stems ha-1, 1734.9 stems ha-1 for saplings and 2217.4 stems ha-1 for seedlings. Comparison of Tulu Korma Forest revealed the highest similarity with Menagesha Suba forest (78%). Analysis of the Regeneration status of this forest indicated that saplings and seedlings were densest when compared with matured trees/shrubs, suggesting good regeneration status that should be maintained.