Overview of Recent Studies on Carbon Dynamics and Budgets in Tropical Forests

Abstract

There have been significant advances in the understanding of the current role of the terrestrial biosphere in the global carbon cycle. Tropical forests playa major role in determining the current atmospheric concentration of CO₂ as both sources of CO₂, following deforestation and sinks of CO₂, probably resulting from CO₂, stimulation of forest photosynthesis. Recently, researchers have tried to quantify this role, and concluded the following results. 1) The productivity of tropical forests might be higher than that previously estimated when below ground productivity is fully taken into account. 2) Recent studies suggest that CO₂, emissions caused by tropical deforestation and degradation might be greater than those previously estimated, perhaps even approaching 3.0 Gt C year^-1 3) Micrometeoro-logical studies based upon the eddy covariance are still limited in number, but suggest a carbon sequestration rate that seems to be larger than 4.5 Gt C year^-1. 4) Studies of the distribution of atmospheric CO₂, find either no tropical source or only a modest source, in spite of the large CO₂ efflux from deforested area, thus indicating the presence of a tropical CO₂, sink of 1-3 Gt C year^-1. 5) There is some consistency between deforestation, forestry plot and atmospheric studies, suggesting a tropical carbon sink of 2.0 Gt C year^-1 a deforestation source of 2.4 Gt C year^-1 and a net tropical source of 0.4 Gt Cyear^-1.