Multi-Scale Remote Sensing of Wildfire Impact and Post-Fire Vegetation Recovery in the Cross-Border Karst Landscape

Wildfires in the Karst Plateau (sln. Kras, ita. Carso) cross-border karst plateau between Slovenia and Italy are becoming more frequent, of larger scale and more devastating. To map burned areas across large areas and track vegetation recovery at finer scales, remote sensing at different scales should be applied. This paper presents a multi-scale remote sensing workflow developed within the KARST FIREWALL 5.0 project for wildfire monitoring in karst landscapes. Satellite imagery was used for regional cross-border analysis of past fires from the 1980s onward, while UAV surveys supported seasonal monitoring at selected local pilot site. Sentinel-2 imagery was used where available for new fires and Landsat data for older fires. Burned areas and vegetation status were assessed with BAIS2 and BAI for satellite images and NDVI for satellite and UAV images. Burn scars were delineated from differences in indices and converted into vector polygons. Out of 682 initial fire records, burned-area polygons were derived for 171 fires. UAV monitoring during the 2025–2026 season was conducted at pilot site in Miren-Kostanjevica municipality which was affected by two past wildfires (2003 and 2022). Seasonal RGB and NDVI interpretation at pilot site showed that vegetation recovery is ongoing but spatially uneven, with better regeneration along vegetation edges and more favourable microsites (dolines), and slower recovery on exposed rocky dry surfaces. Additionally, Sentinel-2 seasonal scenes confirmed the broad recovery trend at landscape scale.