Gross degradation in the tropical dry forests of Mexico forests results in more emissions than deforestation

Tropical dry forests (TDF) are much more densely populated than humid forests in Mexico (as in much of the rest of the world) and local communities use them intensively, causing extensive degradation. As a result, the average above ground carbon stock levels of TDF in Mexico are currently around 14.5 t C/ha (compared to an intact level of 40 to 60 t C/ha).  There could be opportunities under REDD+ for reducing degradation emissions and increasing carbon sequestration in TDF, but these would need to involve local communities and be based on a good understanding of the underlying processes.

One third of the sampling plots of TDF in the national forest inventory showed losses of carbon stock between 2004−7 and 2009−13, resulting in gross emissions from degradation of 22Gg CO₂ per year. This is considerably more than the emissions due to deforestation (around 3Gg CO₂ per year.) On the other hand, two thirds of the sampling plots in TDF showed increases in carbon stock over the period, resulting in gross removals due to forest enhancement of around 40 GgCO₂per year. The enhancements outweighed the emissions, with average standing stock in TDF increasing at a rate of 0.3 tC/ha/year between the periods 2004−7 and 2009−13, indicating that on average stocks are recovering, probably as a result of abandonment of agriculture and out-migration from rural areas. This indicates that gains and losses may be related through cyclical processes such as shifting cultivation or shifting pasture use.  Interventions undertaken under REDD+ need to be based on a good understanding of these processes.

This message is the third of 8 key messages from the WOTROMEX programme.  The case study area is the Ayuquila Basin in western Jalisco, which is a REDD+ Early Action Area under the Mexican national strategy for REDD+. WOTROMEX is supported by the Netherlands Science for Global Development Programme (NWO-WOTRO) and has been carried out by CIGA-UNAM together with the University of Twente, the Netherlands