Carbon Stock and Storage Capacity of Tree Species in Strict Nature Reserve of Omo Biosphere Reserve, Ogun State, Nigeria

Abstract

Carbon is the main casual factor for global warming and climate change. Increased industrialization is known to be the chief contributor to increased atmospheric carbon concentration. Forest ecosystem plays significant role as a major terrestrial carbon sinks that reduces atmospheric carbon concentration. This study assessed the amount of carbon sequestered in the Strict Nature Reserve (SNR) of Omo Biosphere Reserve and the contribution of individual tree species to the carbon stocks. A non-destructive approach was deployed in the study. Systematic random sampling technique was used to demarcate 20 sample plots of 30x30 m. In each sample plot, all tree species (DBH ≥ 10 cm) were identified and measured for their total heights while diameter were measured at breast height (DBH), base, medium and top. Findings indicated 616 stems/ha in the reserve, Strombosia pustulata (63stems/ha) had the highest tree population. Diversity indices showed that the reserve is rich in tree species diversity with potentials for incessant growth due to the existence of young trees in the lower canopy. The high biomass and carbon storage of the tree species revealed the contribution of the reserve to climate change mitigation through co2 absorption from the atmosphere. Ceiba pentandra (9stems/ha) contributed most (26.14%) to the entire carbon stock in the reserve. However higher stem density of tree species hectare-1 did not translate to higher percentage of carbon stock input of the tree species to the entire carbon stock of the reserve. Trees with higher DBH and wood density store more carbon than trees with lesser DBH and wood density. Thus, tree species ability to sequester more carbon is dependent on its DBH and wood density, rather than its population. The need to conserve and increase the tree species diversity is implicated in the study.