Final Report Summary - AFRICA-GHG (AFRICA-GHG: The role of African tropical forests on the Greenhouse Gases balance of the atmosphere)
The role of tropical forests, particularly in Africa, on the global balance of greenhouse gases emissions is still under debate. On one hand tropical deforestation, associated with land grabbing for food production, is a significant contribution to the observed increase of CO2 concentration in the atmosphere (about 0.9 PgC y-1), on the other hand tropical rainforest represent important carbon and biodiversity reservoirs, and through photosynthesis equally important for carbon sequestration. We were able for the first time in a single study for a tropical humid forest to measure simultaneously carbon dioxide, water and energy fluxes, atmospheric depositions of gaseous N compounds and aerosols and CH4 and N2O fluxes. At the same time we have investigated the role of deforestation and selective logging of tropical African rainforest in greenhouse gases emissions, using both remote sensing advanced technologies, such as LIDAR scanning and ground soil emissions measurements.
We have scaled our study at regional level and we have shown that Africa represent a small sink of carbon (−0.61 ± 0.58 Pg C yr−1), but the emissions of CH4 and N2O (2.23 ± 2.12 PgCO2-eq yr-1) turn Africa into a net source of radiative forcing in CO2 equivalent terms.
According to our study the tropical rainforest may contribute to carbon sequestration although not driven by tree growth but instead by organic carbon accumulation in tropical soils.
We have shown that selective logging have a persistent degradation effect on forest biomass and biodiversity which last for more than 30 years (the current harvesting cycle). Conversion of forest to agroforestry system release significant amount of soil carbon to the atmosphere as well as N2O.
Tropical deforestation enhances N2O emissions during the first 20 yrs after cut/burn leading to a significant N2O source which is higher than the contribution of direct N2O emissions coming from N depositions.
We have scaled our study at regional level and we have shown that Africa represent a small sink of carbon (−0.61 ± 0.58 Pg C yr−1), but the emissions of CH4 and N2O (2.23 ± 2.12 PgCO2-eq yr-1) turn Africa into a net source of radiative forcing in CO2 equivalent terms.
According to our study the tropical rainforest may contribute to carbon sequestration although not driven by tree growth but instead by organic carbon accumulation in tropical soils.
We have shown that selective logging have a persistent degradation effect on forest biomass and biodiversity which last for more than 30 years (the current harvesting cycle). Conversion of forest to agroforestry system release significant amount of soil carbon to the atmosphere as well as N2O.
Tropical deforestation enhances N2O emissions during the first 20 yrs after cut/burn leading to a significant N2O source which is higher than the contribution of direct N2O emissions coming from N depositions.