Assessment of the carbon sequestration potential of woody species across major land use types in East Shewa Zone, Oromia, Ethiopia

Carbon storage varies among land-use types due to differences in woody species composition, vegetation structure, soil properties, and management practices. However, the contribution of woody species to ecosystem carbon storage across contrasting land-use types remains insufficiently quantified in many Ethiopian landscapes. This study aimed to assess the carbon storage potential of woody species across major land-use types in East Shewa Zone, Oromia, Ethiopia, by quantifying aboveground biomass carbon, belowground biomass carbon, soil organic carbon, total ecosystem carbon stocks, and carbon dioxide equivalent (CO₂e) storage. Field measurements were conducted across six major land-use types: cropland, grassland, shrubland, tree-dominated land, wetland, and homegarden agroforestry systems. Woody species biomass was estimated using established allometric equations, while soil organic carbon stocks were determined from measured soil organic carbon concentration, bulk density, and soil depth. Carbon stocks varied considerably among land-use types, reflecting differences in woody species abundance, vegetation structure, and management conditions. Tree-dominated land recorded the highest carbon storage, with mean aboveground biomass carbon, belowground biomass carbon, and total ecosystem carbon stocks of 130.7, 34.0, and 319.4 t C ha⁻¹, respectively. In contrast, shrubland and grassland exhibited lower carbon stocks due to limited woody biomass and reduced organic matter inputs. Soil organic carbon was the largest carbon pool, contributing approximately 52% of total ecosystem carbon storage. Homegarden agroforestry systems also maintained substantial carbon stocks, highlighting the role of diverse woody species and continuous biomass inputs in agricultural landscapes. Carbon dioxide equivalent storage ranged from 481.9 t CO₂e ha⁻¹ in shrubland to 1172.2 t CO₂e ha⁻¹ in tree-dominated land. The findings demonstrate that woody species-rich land-use types, particularly tree-dominated landscapes and homegarden agroforestry systems, contribute significantly to ecosystem carbon storage. Promoting woody species conservation and sustainable land management can enhance landscape carbon retention and support climate change mitigation in Ethiopia.