Tree-based carbon sequestration and storage abilities vary in natural and plantation forest ecosystems

Abstract

Little is known about the relevance of natural forests and plantations in the wake of global warming and climate change.
Understanding the impacts of land use conversion from natural forests to plantations on carbon sequestration and storage is critical for sustainable land and forest management. In this study, tree-based carbon sequestration and storage abilities were assessed in natural and plantation forest ecosystems. Four plots within a natural forest and cashew orchard were randomly chosen and four belt transects were established. In each plot, tree species were identified and their density, height, Diameter at Breast Height (DBH) enumerated and measured, respectively. In each plot, litter boxes were placed to collect litter weekly. Soils (at 0 -15 cm and 15 – 30 cm) within each plot were obtained with soil auger. AGB (aboveground biomass), BGB (belowground biomass), AGC (aboveground carbon) and BGC (belowground carbon) were calculated using allometric equations for pan moist and dry tropical forest. Twenty-three and eleven tree species were found in the forest and orchard, respectively. The forest had the largest total biomass allocation (188.61 Mg ha^-1) and carbon stock (146.89 Mg C.ha^-1) while the orchard had the least total biomass apportionment (37.20 Mg ha^-1) and carbon stock (45.60 Mg ha^-1). The forest ecosystem had the largest sequestration ability (593.04 Mg CO2ha-1) which followed this trend: aboveground (295.18 Mg CO₂ha^-1) > belowground (60.51 Mg CO₂ha^-1) > soils (133.73 Mg CO₂ha^-1) > litter (49.62 Mg CO₂ha^-1) while cashew orchard had the least sequestration ability (167.37 Mg CO₂ha^-1) which followed this order: soil (99.09 Mg CO₂ha^-1) > litter (35.75 Mg CO₂ha^-1) > aboveground (27.00 Mg CO₂ha^-1) > belowground (5.53 Mg CO₂ha^-1). From these results, land use change affects carbon budgets of ecosystems, hence, this study argues for protection of natural forest while practicing afforestation towards global warming mitigation.