An integrated remote sensing and AHP framework for forest fire vulnerability assessment in Gironde, France

Abstract

Forest fires pose a significant environmental hazard in southwestern France, where increasing fuel accumulation, human activities, and climatic extremes have intensified fire occurrences in recent decades. This study developed a high-resolution forest fire vulnerability map for the Gironde department by integrating remote sensing, GIS-based modeling, and the analytical hierarchy process (AHP). A comprehensive geodatabase comprising twelve conditioning factors related to vegetation and fuel characteristics(e.g., forest fuel type and land cover), climate and weather variability, topographic constraints, and human influence was developed to support the vulnerability assessment. A 12 × 12 AHP pairwise comparison matrix generated a consistent weighting scheme (CR = 0.046), and the resulting criteria weights were applied through a weighted sum model to derive the forest fire vulnerability index (FFVI). A key contribution of this study is the integration of multi-source geospatial data with a validated multi-criteria decision-making framework to produce a high-resolution forest fire vulnerability assessment, an approach not previously applied to the Gironde region. The model demonstrated strong predictive performance when validated using 699 active fire detection points obtained from the fire information for resource management system (FIRMS). The ROC analysis produced an AUC of 0.721, indicating good discriminatory performance, and 87% of fire ignitions fell into the high and very high vulnerability groups. Additionally, the success rate curve (SRC) yielded an AUC of 0.86, confirming excellent model performance. Spatial analysis indicated that southwestern Gironde exhibited the highest forest fire vulnerability because of its extensive maritime pine forests, low vegetation moisture, and proximity to anthropogenic features. The resulting vulnerability map provides a practical decision-support tool for strategic fire prevention, targeted fuel management, land-use planning, risk mitigation, and early warning.