Tropical forests are acknowledged for their significant wealth essential to the well-being of people of the world. The study was done at Gidabwanja Forest Reserve (GFR) in 2022 to assess the human disturbance on tree species regeneration diversity and dominance. The 10 m x 20 m were set to assess trees with DBH (cm) ? 5 cm; 2m x 5m nested plots for saplings and poles, and 1 m x 1 m for seedlings. The identified trees were counted for individuals. The H? was calculated , and ID through; ID = ?pi2. Single factor ANOVA test was used to evaluate the significant differences within the tree growth stages. GFR was known to consist of wood land, bush land, and shrub land. Of the 30 sample plots, 14 (46.7%) fell under WL, 14 (46.7%) were BL; while only two plots (2) (6.6%) were SL. Tree level scored the highest number of species (49) of all others, followed by pole(s) (27), sapling (26), and seedling (10), making an overall of 51 trees species. The highest H? was revealed in mature trees (3.21), followed by pole (3.01), sapling (2.89), and seedling was the least (2.19), revealing high diversity of all levels of growth. The H? of 2.825 implies high diversity. Both S and H? revealed a descending trend of regeneration stages from tree towards seedling stage. Of the 51 tree species, 30 got seedling, sapling, pole, and tree stage. This implies that mature trees of the rest 21 species will disappear. The recorded highest pi2 in tree stage ranged from ?0.03679 – ?0.00267, for poles was ?0.005 - ?0.00, sapling was ? 0.025 – ?0.004, while for seedlings ranged from ?0.049 – ?0.012. The ANOVA test F-value of 0.57 for H? and 0.65 for pi2 indices were > 0. 05, revealing a significant difference within growth stages. The recorded human disturbances were charcoal, pole, debarking, firewood, grazing, local beehives logs, farming, settlement, snaring, and stone collection. The GFR high diversity of tree species with successive growth stages. It is high time for TFS to upgrade the GFR into nature reserve to encourage non-consumptive resource utilization, further studies, participatory regular patrols, agro-biodiversity system introduction to community, and diversification of income generation activities.

Keywords: Richness, Shannon wiener diversity index, Simpson index