Greenhouse gas mitigation potential of combining forest management and bioenergy substitution: a case study from Central Highlands of Michoacan, Mexico.

摘要

Key to climate change abatement strategies is the understanding of the comparative carbon mitigation implications of management of native forests oriented to different end-uses such as conservation, conventional management, or integrated management that includes bioenergy. In Mexico 95% of total logging is conducted in native forests, and 80% of it in pine (Pinus)-oak (Quercus) forests. We compare the carbon mitigation dynamics of mixed native pine-oak forests in Central Mexico under current management - used as a reference scenario - with two alternative scenarios: (a) oak conservation and (b) oak conservation + bioenergy. To estimate the carbon fluxes for each scenario and each forest type we used the CO2FIX V3.1 model, a user-friendly tool designed to calculate all carbon fluxes in forest stands, forest-derived products and bioenergy technologies based on forest slash and industrial residues. The CO2FIX model applies a cohort-type approach to estimate carbon fluxes in mixed or uneven-aged forests where species groups or age cohorts typically show differences in growth, biomass allocation, intra and inter-cohort competition, and mortality. The product module tracks the carbon in products derived from the forests until the decomposition is complete, whereas the bioenergy module compares total greenhouse gas dynamics of reference and alternative bioenergy technologies, applying IPCC guidelines to estimate the carbon equivalence of the various greenhouse gases. We compare the outcome of the three scenarios in a managed community forest of about 11,000 ha in Michoacan, Central Mexico. The carbon mitigation potential after 20 years varied between 8.2 and 19.3 tonnes C/ha for the oak conservation scenario and between 21.6 and 42.9 tonnes C/ha for the oak conservation-bioenergy scenario. The bioenergy scenario results in a continuous stream of approximately 1.36 tonnes C/ha of carbon benefits per year, whereas the oak conservation scenario will stop accumulating carbon after 40 years, compared to current forest management and energy generation..