It's a keeper: Valuing the carbon storage service of Agroforestry ecosystems in the context of CAP Eco-Schemes

Abstract

Agroforestry landscapes provide multiple benefits, including the capacity for storing carbon, thus contributing to climate change mitigation. In Portugal, the agroforestry system known as Montado (Dehesa in Spain) is heavily dependent on national and European financial incentives. Lack thereof, or insufficient level, often results in abandonment or intensification (increasing grazing pressure) of management practices. Carbon storage is a stock externality of agroforestry systems currently not targeted by CAP agri-environmental mechanisms. Hence, our work is aimed at assessing and valuing net carbon flow in agroforestry systems to guide a Payment for Ecosystem Services (PES) scheme targeting Montado landscapes in Portugal. We have assessed and valued net carbon flow for different land-use change scenarios (abandonment, maintenance, or grazing intensification), focusing on cork and holm oak-dominated Montado and using biomass equations. We applied different explicit carbon pricing mechanisms (market value, social cost, and shadow price) to determine a range of values suitable as financial rewards in the proposed PES scheme. For cork-oak Montado, our results suggest both abandonment and grazing intensification are linked to carbon emissions (−1.5 and −1.6tCO2eq.ha-1.year-1, respectively), whereas maintaining Montado results in carbon sequestration (+0.9tCO2eq.ha-1.year-1). Similar results were found for holm oak. Based on this biophysical assessment, we estimate that farmers willing to maintain Montado systems are eligible to be rewarded between 106 and 149€.ha-1.year-1 through a PES scheme for the increase in carbon storage they are providing. Incorporating the value of ecosystem services into direct financial rewards could ensure agroforestry systems are kept under sustainable management and continue to supply multiple benefits to society.