Forest fire risk assessment and multifunctional fuel treatment prioritization methods in Mediterranean landscapes

In Mediterranean areas, the combined effects of the rural exodus, lack of forest management, and fire suppression policies have substantially contributed to increased forest fuel loadings and continuity over large areas. The result is a growing incidence of wildfires that exceed fire suppression capacity. Economic resources for landscape management are limited, and thus they must be prioritized towards the protection of valued assets where there is a high expectation of loss and the fuel treatments on strategic locations that restrict fires spreading into communities. We completed a case study in the Juslapena Valley (Navarra, Spain) to demonstrate prioritization of fuel management activities. The study area has frequent and large forest fires that have caused significant damage to forest values and assets in rural communities. We first generated a wildfire risk map for valued assets, and then designed the optimal treatment mosaic within the community fireshed considering the wildfire exposure to forestlands and fire transmission to residential housing. We also identified overstocked stands where the timber or firewood production might supply the needs of local communities and partially cover the treatment cost. We found that the highest economic losses were obtained in residential houses located in the southern portion of the study area, mainly due to a higher burn probability. Fires ignited outside of the study area also exposed communities, and thus the extent considered in wildfire management plans needs to be adjusted to reflect the source and scale of risk to communities. The assessment framework presented in this study can be adapted to the multi-functional forest management in any fire-prone Mediterranean region elsewhere.