FLORISTIC COMPOSITION, STRUCTURAL ANALYSIS AND REGENERATION STATUS OF WOODY PLANT SPECIES IN DABAL FOREST, EAST HARARGHE ZONE, OROMIA, ETHIOPIA

Abstract:

The study was conducted in Dabal forest to investigate the floristic composition, population structure and regeneration status of woody plant species (WS) in the forest. 52 nested quadrats of the size 20m × 20m, 10m x 10m and 5m × 5m for tree/shrub, sapling and seedling respectively, were laid systematically along seven line transects. For each quadrat, variables such as altitude, longitude and latitudes were recorded by using Garmin 62 GPS. A meter marked stick was used to measure the height of WS in order to define them as seedling, sapling and mature tree/shrub. Diameter at breast height (DBH) of all mature tree/ shrub was measured by using a mater tape. Results of the study revealed that a total of 59 woody species representing 53 genera and 33 families were recorded in the forest. The Shannon Weiner diversity index and evenness values of the forest were found to be 3.56 and 0.87 respectively. Out of 59 woody plant species, 27(45.77%) were trees, 24 (40.68%) shrubs, (8.47%) tree/shrubs and (5.08%) Shrub/Liana. Fabaceae was the dominant family represented by 6 species (10.17%) followed by Euphorbiaceae and Moraceae 4 species (6.78%) each. Tree/shrub, sapling and seedling densities were 834.13, 1032.69 and 1507.69 individuals/ha respectively. The total basal area (BA) of Dabal forest was 19.06 m2 ha-1 . The cumulative DBH class distribution of the forest showed inverted-J shape. Analysis of the regeneration status of WS in the forest showed 44% good, 37.3% “fair”, and 8.5% “poor”. Two species were not regenerating and four species were recorded as new to the area. The relatively lower basal area of the forest and poor regeneration of some species suggests that the forest needs to be protected and utilized in a sustainable way in addition to planting indigenous tree species in areas of depleted tree population.