Documentation of Historical Forest Fires and Hazard: Case of Gironde and Les Landes, France

Abstract. Forest fire is becoming an important research topic because of climate change and its impact on population. In this study, historical database about forest fire incidents was created for Gironde and Les Landes (1989 to 2022). To the knowledge of the authors, this database did not exist before. The database is essential in showing spatial and temporal distribution of forest fires and helps in decision-making. The database was created from newspapers and crosschecked with burned areas visible on Landsat and Sentinel-2 satellite images. Several factors were used to generate a forest fire hazard map such as vegetation water content utilizing Normalized Difference Moisture Index (NDMI), type of vegetation, topography, and barriers to the expansion of fire (proximity to water bodies and roads). All layers were converted to raster format and reclassified to a common scale. Weighted overlay in GIS was used to generate the final forest fire hazard map. Results showed that, temporally most forest fires occurred during March-April and July-August and majority are in Gironde. The hazard map highlights that most of Les Landes and Gironde departments are vulnerable to this hazard because of their extended forest areas and high dryness. The accuracy assessment showed that supervised classification had the best accuracy followed by the Burned Area Detection Index (BADI) and the manual digitization. Data from French institutions and higher-resolution satellite images could improve the accuracy of the historical forest fires database. The output from the study was made available to the public for further exploration (https://firemap.saro.app/).