How global bioeconomy policies and local fire management drive Mediterranean forest landscapes and their associated fire regimes

Abstract

Europe's bioeconomy policy seeks to diversify the energy sources for industrial purposes through the gradual replacement of fossil fuels by the sustainable use of renewable biological resources (e.g. forest products), and therefore, to contribute to the mitigation of ongoing climate change. Sustainable harvesting levels of forest biomass to meet future demands of bioenergy and wood-based products need to be carefully evaluated, in order to minimize the potential negative impacts of forest exploitation/use on forest ecosystem functioning (and services provisioning) and on their associated biodiversity values. In this study we explore the effects of three European-level bioeconomy scenarios on the coverage of Mediterranean forests, their spatial distribution, and the fire regime (fire frequency and fire size) in Catalonia, a Mediterranean fire-prone region currently dominated by an agro-forest mosaic. The 'Business-as-usual' scenario assumes that no new bioeconomy policies are implemented, the 'EU bioenergy' scenario aims to reduce greenhouse gas emissions in EU28 by increasing bioenergy production, and the 'Global bioeconomy' scenario seeks to enhance a full development of bioeconomy based on bioenergy and the use of biomaterials. We first downscaled to the study region the outputs of GLOBIOM model, a global market equilibrium model that analyzes the competition for land use between the agriculture, forestry, and bioenergy sectors. It generates national-level demands for industrial roundwood and biomass for energy production. We link the outputs of the GLOBIOM to the MEDFIRE model. The MEDFIRE is a regional spatially explicit landscape dynamic model that accounts for vegetation growth, drought-induced mortality, establishment after fire, and afforestation. It incorporates a forest management and land-use change module, and also simulates fire behaviour and fire suppression actions. The combination of the two models allow us to obtain future spatially explicit projections of the Mediterranean forests distribution and coverage on an annual basis from 2010 to 2100, under each bioeconomy scenario. Results show that fire regime is progressively altered, both fire frequency and fire size will increase, in both bioenergy based scenarios due to a positive feedback between more fuel load availability and more severe climate. However, an increase on fire incidence reshape forest structure and compromise future wood demand to meet the bioenergy policies. Scenario projections will be further used to evaluate the potential impacts of each bioeconomy scenario on the provision of ecosystem services linked to Mediterranean forests, as well as their potential effects on biodiversity values. The work presented here is part of the Sumforest project FutureBioEcon.