Woody plant species diversity, vegetation structure, and regeneration status of Modi-Geyi Forest in Andracha District, Southwest Ethiopia

The Modi-Geyi Forest, a moist Afromontane forest in southwestern Ethiopia, is an important biodiversity reservoir that provides critical ecological services and supports local livelihoods. However, increasing anthropogenic disturbances and land-use pressures threaten its woody species diversity, vegetation structure, and regeneration capacity. Assessing its ecological status is therefore essential for guiding conservation strategies. Fifty 20 × 20 m plots (400 m² each) were systematically established along five transects, with 200 m spacing between plots and 500 m between transects. Two 5 × 5 m subplots were nested within each main plot to assess seedlings and saplings. All woody plants with DBH ≥ 2.5 cm were identified and measured. Species diversity indices, vegetation structure (DBH and height class distributions), regeneration status, and ecological importance based on the Important Value Index (IVI) were analyzed. A total of 56 woody species, representing 51 genera and 30 families, were recorded. The DBH and height distributions followed an inverted J-shape, indicating ongoing regeneration. However, some species, including Brucea antidysenterica J.F.Mill. and Phoenix reclinata Jacq., showed poor regeneration. The forest had a total basal area of 119.84 m² ha⁻¹, with Aningeria adolfi-friederici (Engl.) Robyns & Gilbert, and Schefflera abyssinica (Hochst. ex A.Rich.) Harms as dominant species by IVI. Despite generally positive regeneration, localized degradation from agricultural expansion, overgrazing, and firewood collection was evident. Modi-Geyi Forest supports moderate woody species richness and shows signs of regeneration. However, selective pressure on key species and site-specific disturbances highlight its ecological vulnerability. Conservation efforts should prioritize the protection of poorly regenerating species and the restoration of degraded patches to maintain long-term forest stability.