全球变化知识资源中心

Land use/land cover change tends to play a more critical role in controlling CO2 emissions and annual storage. Despite the fact that the majority of the deforestation and forest degradation and consequent emissions have been occurring in tropical developing countries, little or no direct quantifications of the effects of land use change on the Carbon pools of these land use systems have been done. Taking into consideration four (4) land use systems in Ekiti State, South-western Nigeria, we quantified the magnitude of biomass and biomass carbon stocks in the following carbon pools: trees, non-woody vegetation, litter, coarse woody debris and roots. Total biomass carbon stocks of the different land use land cover types decreased in the order: Natural forests (NF) (155.61 Mg C ha(-1)) > Plantations (TP) (80.37 Mg C ha(-1)) > Woodlands (WD) (41.17 Mg C ha-1) > Croplands (CP) (35.33 Mg C ha(-1)). Approximately 50% of the total vegetation carbon stocks are contained in natural forests in the study. Estimation of C stocks in Necromass pools is important for carbon quantification most especially in the croplands and agroforestry ecosystems. Natural forest of all the land use types has the greatest biomass carbon storage potential with an estimated standing stock of 155.61 Mg C ha(-1) while cropland has the least carbon storage with a measured standing stock of 35.33 Mg C ha-1. We observed a reduction of 120.28 Mg C ha(-1) and 75.24 Mg C ha(-1) of the total biomass carbon stocks as a result of a change of natural forest to croplands and plantations, suggesting important C loses in the ecosystems. Improving our knowledge of terrestrial sources and sinks of CO2 and other greenhouse gases (GHGs), and their spatiotemporal variability is a key action to better understand and predict the global change and enhance human capacity to undertake mitigation and adaptation strategies.