The study was conducted on Gelesha Forest, Godere District and Gambella Regional State, Southwest Ethiopia to determine floristic composition and structural analysis of the forest. Systematic sampling method was used to collect vegetation data from 60 plots (20 m × 20 m) for trees and shrubs, 5 m x5 m for seedlings and saplings and 1 m × 1 m for herbaceous plants. Vegetation classification was performed using PC-ord software package. All trees and shrubs with DBH >2 cm and height >2 m were measured for diameter tape. A total of 157 species of vascular plants belonging to 127 genera and 54 families were recorded from Gelesha Forest. Of all the species recorded 33.12% were trees, 19.11% shrubs, and 13.38% woody climbers. The dominant families were Euphorbiaceae and Moraceae (13 species each): 11 and 6 genera, respectively. The density of trees in the forest decreases with increasing DBH classes. Six population distribution patterns were recognized. The Forest has a density of 557.09 stems/ ha and a total basal area of 98.87 m2/ ha. The forest is characterized by high density of trees in the lower class than in the higher. Phytogeographically, it was more related to the moist evergreen Afromontane forests of the Southwest Ethiopia than other forests in the country.
Key words: Forest structure, Gambela region, regeneration, species diversity, vegetation composition.