THEASSESSMENT OF WOODY PLANT SPECIES DIVERSITY, STRUCTURE AND REGENERATION STATUS, THE CASE OF UDDOTU FOREST, BIRBIRSA KOJOWA DISTRICT,WEST GUJI ZONE, OROMIA, ETHIOPIA

<strong>Abstract</strong>: The study was conduct at Uddotu Forest in Birbirsa Kojowa District, West Guji Zone, Oromia Region, Southern Ethiopia. The objective of this study was to assess the Woody plant species diversity, structure and regeneration status of the forest. 64 quadrates of 20mx20m (400m2) were laid along Eight lines transects for woody plant data collection. Shannon Wiener diversity index was used to assess species richness and evenness. Sorensen's similarity coefficient was used to measure similarities among communities. A total of 79 plant species in 71 genera and 46 families were identified. Of these woody plant species, 44 (55.67%) were trees, 24 (30.38%) were shrubs, 7 (8.86%) were woody lians and 4 (5.06%) were herbs. Fabaceae is the most abundant family with 10 species followed by Sapindaceae and Oleaceae each with 4 species. The overall Shannon–Wiener diversity (H’) and evenness (J) of woody species in Uddotu forest were 3.6 and 0.83, respectively. The species with the highest density was Syzyguim guineense (19.34%) followed by Trichilia dregeana (19.02%) Prunus africana (17.19), Chionanthus mildraedii (15.63%) Leonotis ocymifolia (15.34) and Fagaropsis angolensi (14.45%). Aningeria adolfi-frendicii was the tallest tree with maximum height attaining up to 40 m followed by Millettia ferruginea, 38 m and Prunus africana and Syzygium guineense 30 m. Woody plants in the study area were classified into six DBH classes. The total BA of the study area was 45.77 m2 ha−1. About 43.11% of the total BA of the woody plant was covered by Syzyguim guineense (21.41%), Cordia africana (5.96%), Albizia gummifera (4.69%), Hagenia abyssinica (4.15%), Podocarpus falactus (4.13%) and Fagaropsis angolensis (2.77%). The area was dominated by Syzygium guineens, Cordia africana, Albizia gummifera, Hagenia abyssinica, Podocarpus falactus and Fagaropsis angolensis. The forest had a total of 196 seedlings ha−1, 167.7 saplings ha−1, and 116.7 matured plants ha−1. The ratio of seedlings and saplings to the matured woody plants was 1.68 and 1.44, respectively. Community based training in forest management and utilization could result in a positive attitudinal change of the local people towards sustainable utilization, protection and conservation of natural forest, and is thus recommended. Lastly, Vernonia auriculifera, Allophylus abyssinicus and Milletia ferruginea should receive appropriate conservation measures, due to their status of threatened species.