A Cost-Benefit Analysis Of Carbon Sequestration In Trees In The Northern Part Of Adamawa State

Trees are among the most effective and readily deployable natural mechanisms for removing atmospheric carbon dioxide, yet the economic value of this service remains poorly quantified for the savanna woodlands of northern Adamawa State, Nigeria. This study estimated the above-ground biomass (AGB), below-ground biomass (BGB), total biomass and carbon storage of sixteen dominant tree entries recorded across a GIS- and remote-sensing-supported field inventory of the study area and evaluated the monetary cost and benefit of the resulting carbon sequestration. AGB per tree was derived using the pantropical allometric model of Chave et al. (2014), which combines diameter at breast height, total height and species wood density; BGB was estimated using a root-to-shoot ratio of 0.24, and carbon content was driving by applying the IPCC (2006) default carbon fraction of 0.47 to total dry biomass. A total of 3,219 trees across the sixteen entries were assessed, yielding an estimated 4,621 tons of total biomass, 2,172 tons of stored carbon, and 7,964 tons of carbon dioxide equivalent (CO2e). On average, a single tree in the inventory sequesters approximately 2.47 tons of CO2e, valued between US$17 and US$59 (≈₦23,639–₦81,046) depending on the carbon-price scenario applied, with a base-case value of approximately US$24.74 per tree. At a conservative voluntary-carbon-market price of US$10/tCO2e, the entire inventory represents a stored-carbon asset worth approximately US$79,636 (≈₦108,703,496), against an estimated establishment and protection cost of US$451–US$14,486, producing benefit-cost ratios ranging from 5.5 to 176.7. Anogeissus leiocarpus, Khaya senegalensis and Vitellaria paradoxa together accounted for approximately 70% of total carbon stock. The results demonstrate that conserving existing savanna trees in northern Adamawa State is a highly cost-effective climate mitigation strategy and provide a replicable framework for scaling carbon stock assessment across the wider Sudano-Sahelian belt of the state.