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 

Video ´Opportunities for REDD+ in the Tropical Dry Forests of western Mexico´

This video will be shown at our presentation in the Holland Pavilion in Paris on December 4th.  A short preview can be found at:   https://youtu.be/rCJPgdd_vWQ

Well-enforced command and control mechanisms and greater inter-sectoral coherence, not direct payments, may be the best solutions in the long run to reducing deforestation

Although it is possible to establish that some geographical areas are more at threat from deforestation than others, it is very difficult to identify exactly who is going to deforest in a given period of time.  This means that payments for ´not deforesting´ would have to be given to far more forest owners than would, in reality, have deforested.  Given also the relatively high opportunity costs of deforestation, this would result in low cost efficiency. Moreover, any such payments would likely result in leakage, as demand for pasture or agricultural land would simply shift to other locations. 

Although PES may be part of the solution under REDD+, it does not address the causes of deforestation.  Given the relatively high opportunity costs of deforestation, well-enforced command and control mechanisms may be a long run solution to reducing it. Dealing with the lack of coherence between agricultural policies (which often promote clearance) and environmental policies (which aim to reduce deforestation) at the local level and at the national and regional level would be a major step forward, but sectoral autonomy is a political reality and reaching agreement between institutions may be a challenge.

This message is the second 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 

The opportunity costs of degradation

There have been several studies of the opportunity costs of deforestation in the context of REDD+, for example in preparation for the Stern Report (Greig Gran 2008, http://pubs.iied.org/pdfs/G02489.pdf)    and for the World Bank   (Chomitz, 2007 http://www-wds.worldbank.org/external/default/WDSContentServer/WDSP/IB/2006/10/19/000112742_20061019150049/additional/ixviiiPRRALFMweb.pdf)  but very little is known about the opportunity costs of degradation.  In InfoBrief 6 we present some estimates of the opportunity costs of degradation for the case of shifting cultivation in western Mexico.  Not only are these costs high, they also vary greatly according to farming style.  This introduces a social dimension which has not been present in studies of opportunity costs earlier.  For InfoBrief 6 please see the side menu.

In Mexico tropical dry forests are being deforested faster than other types of forest

Between 2007 and 2011, average loss of area of TDF in Mexico was about 0.33% per year, compared to 0.2% per year for all forest types.

The primary cause of the loss of TDF forest in the study area in Jalisco was conversion to improved grass lands (seeded pastures) and scrublands (unseeded grazing areas). A much smaller proportion was converted to agriculture (shifting or permanent). Recuperation was mainly from scrubland. The largest pool of carbon in the TDF in the study area is in the soil (including both soil organic carbon and mineral carbon). In both absolute and relative terms there is more soil carbon per hectare in areas under shifting cultivation and under fallow following shifting cultivation, than in old growth forests. Soil carbon forms between 64% of the total carbon in old growth forests and 88% in the fallow areas. However, the soil carbon stocks in areas which have been opened for permanent agriculture are less than half those under shifting cultivation.

This message is one 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