Ecosystem carbon stock and socio-ecological determinants in selected agroforestry practices at the eastern escarpment of Chercher Massive, Ethiopia

Several studies have recalled to narrow the gap of information on carbon (C) storage capacity and the extent of its relationship with socio-ecological factors in agroforestry (AF) land use systems. The aim of this study was to determine the C storage capacity of coffee-shade-tree based (CT-AF) and fruit-tree based (FT-AF) AF practices, and the effects of elevation, slope, household wealth status (HHw) and stand structures on C storage. The total agroforestry practice carbon stock (TAPCS) was determined as the sum of the estimated total plant biomass C and soil organic carbon (SOC). The mean total AF practices C stock (TAPCS) for the CT-AF and FT-AF practices were found to be 113.52 tC ha⁻¹ and 141.58 tC ha⁻¹ respectively. The SOC shared 71.7% of the TAPCS. The analysis of the linear mixed model showed that biomass C stock was significantly influenced by AF practices, HHw, diameter at breast height (DBH) and by the interaction of basal area (BA) with DBH. The total SOC was influenced by AF practices, elevation, slope, HHw, DBH and two-way interaction of elevation with HHw, and three-way interaction of AF practices, elevation and slope gradients. The TAPCS was significantly affected by AF practices, elevation, BA, DBH, two-way interaction of AF practices with elevation, elevation with HHw, and interaction of DBH with BA. The studied AF practices can, on average, sequester more carbon dioxide (C) than other tropical tree-based ecosystems. This study reveals that the AF practices could serve as substantial C sinks and contribute in climate change mitigation in addition to their livelihoods provision for a majority of farming households. The information would benefit both researchers and policymakers, as AF has been promoted as an eco-friendly way to mitigate the effects of climate change. Hence, in order to maximize biomass production, store carbon, and mitigate climate change on smallholder farms, future AF landscape tree enhancement strategies need to take into consideration the different AF practices in relation to elevation, slope, household wealth status, and stand structures.