Biomass and Carbon Sequestration Potential of Orisunbare–Apoti Forest Reserve, Osun State, Nigeria
1,* Olajiire-Ajayi, B.L. and 2 Ogundana, O.A..
1,2 Department of Forestry and Environmental Technology, Federal College of Forestry, Jericho, Ibadan
DOI: 10.36108/laujoces/6202.61.0210
Abstract
Orisunbare–Apoti Forest Reserve is an important remnant forest Reserve in Osun State, southwestern Nigeria. However, field-based estimates of its biomass and carbon stock have been limited. This study assessed stand structure, biomass, carbon stock, and carbon sequestration potential. A total of ten 20 m × 20 m plots established across the reserve. All trees with Diameter at Breast Height (Dbh) ≥ 5 cm were measured using a diameter tape, while tree height was measured using a Haga altimeter. Species-specific wood density values were obtained from global databases. Above-ground biomass (AGB) was estimated using the pantropical allometric model while belowground biomass, total biomass, carbon stock, and CO₂ equivalent were derived using standard forest carbon methods. Results showed variability in stand structure. Tree density ranged from 12 to 21 trees per plot, mean Dbh from 37.30 to 74.08 cm, mean height from 8.16 to 11.09 nm, and basal area from 52.89 to 203.21 m² ha⁻¹. Total biomass was 40,635 kg, carbon stock was 19,290 kg, and CO₂ equivalent was 70,820 kg. Linear regression indicated that basal area had a highly significant positive effect on carbon stock (β = 11.13, p = 0.0015). Similarly, multiple regression confirmed basal area as the strongest predictor of carbon stock (β = 9.84, p = 0.009), both significant at the α = 0.05 significant level. The study concludes that the reserve has notable carbon sequestration potential and can support Reducing Emissions from Deforestation and Forest Degradation (REDD+) planning, forest conservation, and long-term monitoring in Southwestern Nigeria.
Keywords: Carbon sequestration; Forest Carbon stock; Climate change mitigation; Tropical Forest reserve; REDD+
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