Urban homegardens are important refuges for native biodiversity and climate change mitigation. This study investigated the potential of homegardens and government institution tree-planted, compounds for conservation of woody species and carbon sequestration in Jimma City. A complete counting of woody species within 138 homegardens and 39 sample plots (each 10 m × 10 m) placed in government institutions were surveyed. Diameter at breast height and height of the tree were measured. Allometric equation was used to estimate woody biomass carbon, showing 884.2 Mg C ha-1 (homegardens) and 1,992.95 Mg C ha-1 (government institutions). A total of 40 woody species (36 in homegarden and 22 in government institution) of 24 families were recorded. Significantly higher (P < 0.001) species richness and diversity were observed in homegardens. But no significant difference was found (P > 0.5) among homegardens in three kebeles (the smallest administrative unit). Jaccard coefficient of similarity index showed low similarity in woody composition between two systems and higher similarity between homegardens. The result revealed that homegardens in Jimma City have good potential for biodiversity conservation and climate change mitigation. Hence, the role of homegarden in maintaining native biodiversity and climate change mitigation must be prioritized in urban development planning.

Keywords: Biodiversity conservation, government institution compound, carbon stock, climate change mitigation