Urban areas face significant challenges due to global warming and climate change. In Nigeria, the situation is particularly serious because of high deforestation rates. To address this, numerous research initiatives are focusing on ways to reduce the impacts, especially looking at the potential of different tree species to store carbon. This paper assessed the aboveground biomass (AGB), carbon stock (CS), and carbon sequestration potential of tree species at the Nigeria Institute of Social and Economic Research (NISER) in Ibadan, using total enumeration. The study used a non-destructive approach to estimate the biomass of various tree species. All the tree species with a diameter at breast height of ≥10 cm were identified. The height and diameter of each tree were measured and wood density for each species was obtained from an online global database. These measurements were used to estimate AGB, total biomass (TB), CS, and CO2 sequestration potential. A total of 139 trees belonging to 22 species and 14 families were identified within the NISER office premises. The total estimated biomass was 4,494.19 kg, with total carbon storage at 2,247.09 kg and total CO2 sequestration at 8,246.83 kg. Out of the estimated total biomass, the aboveground portion was 3,566.81 kg, while the below-ground portion was 927.37 kg. The results indicated that Albizia lebbeck, Tectona grandis, Mangifera indica, Casuarina equisetifolia, and Elaeis guineensis displayed strong capabilities in aboveground biomass, carbon storage, and sequestration. In conclusion, NISER hosts a diverse range of tree species, contributing to biodiversity conservation and improving the climate. It is recommended that Research institutions and private establishment within the region should plant more trees to create greener environments that can support sustainability. This can be enhanced if the government provides adequate incentives, such as long-term funding for monitoring, robust technical support, and streamlined partnerships for the institutes that maintain the best green spaces.