Comparative analysis of carbon sequestration potential of agroforestry systems in Habro District, Eastern Ethiopia

Agroforestry systems offer a promising nature-based solution for climate change mitigation by enhancing carbon (C) sequestration in both biomass and soils. This study was conducted in Habro District, West Hararghe Zone of Oromia, Ethiopia, to assess and compare the carbon stock potential of parkland and coffee-based agroforestry systems. Habro District was purposefully selected due to its prevalent agroforestry practices. A total of 32 farm plots (16 from each system) were randomly selected from two kebeles. Field measurements included vegetation inventory, soil sampling at two depths (0–20 cm and 20–40 cm), and biomass assessment using species-specific and general allometric equations. Results indicated that coffee-based agroforestry systems had significantly higher total biomass carbon stock (33.94 ± 3.11 Mg C ha⁻¹) compared to parkland systems (10.28 ± 0.83 Mg C ha⁻¹). Similarly, soil organic carbon (SOC) stocks were higher under coffee-based systems, with a mean value of 158.1 ± 8.24 Mg C ha⁻¹, compared to 114.44 ± 6.5 Mg C ha⁻¹ in parkland systems (p < 0.05). The total ecosystem carbon stock in coffee-based systems reached 192.64 ± 10.9 Mg C ha⁻¹, significantly surpassing the 124.72 ± 8.01 Mg C ha⁻¹ recorded in parkland systems. The superior performance of coffee-based systems is attributed to denser tree cover, lower soil disturbance, and greater litter input. The study confirms the critical role of agroforestry, particularly coffee-based systems, in enhancing carbon sequestration while supporting local livelihoods. These agroforestry systems act as nature-based solutions (NbS), sequestering substantial carbon in both biomass and soils while simultaneously supporting local livelihoods and farm resilience. It highlights the opportunity for integrating agroforestry into national climate strategies such as Ethiopia’s NDCs, REDD+, and AFR100. Furthermore, the findings provide baseline data for carbon accounting essential for linking smallholder farmers to carbon finance mechanisms under the Clean Development Mechanism (CDM) and voluntary carbon markets.