CARBON DYNAMICS OF MEXICAN TROPICAL EVERGREEN FORESTS - INFLUENCE OF FORESTRY MITIGATION OPTIONS AND REFINEMENT OF CARBONFLUX ESTIMATES

Tropical evergreen forests (TEF) of Mexico were deforested al a rate o f approximately 206,000 ha/yr with a carbon (C) efflux of nearly 21 Tg /yr between 1980 and 1993. Land formerly occupied by these forests hav e potential to mitigate greenhouse gas emissions. In this paper, we mo del two management scenarios in southeast Mexico and their effects on CO2 flux. We also model two scenarios to examine possible adjustments to the region's net C-flux estimate by accounting for regrowth of degr aded forests and increase of C stocks in mature forests. Potential TEF distribution in the study area and current forest inventory data from Mexico's National Periodic Forest Inventory are compared to calculate areas available for modeling land-based C flux. The CO2FIX model was used to evaluate potential C sequestration of mahogany plantations. Po ssible C conservation through reduced deforestation in TEF is evaluate d by a simple spreadsheet model, as are improvements to the region's C -flux estimates from degraded land regrowth and C accretion in mature forests. Total C sequestration modeled in the four scenarios accounted for up to 31 Tg/yr. This illustrates the significant impacts that lan d management may have on carbon balance estimates and accounting for a portion of the missing global carbon sink.