LiDAR-Based Analysis of 19th-Century Fortifications in the Reims Region (France): Morphogenesis, Geoheritage, and Environmental Impact

Following the Franco-Prussian War (1870–1871), the French government launched the ex nihilo construction of 234 forts, built using a variety of geomaterials and covered with massive earthworks involving several tens of thousands of cubic meters of fill. In Reims (northeastern France), a belt of 13 detached forts was constructed and modernized between 1875 and 1892, later integrated into the defensive networks of the WW1. This PhD research offers a morphological analysis of the "Séré de Rivières" fortifications, anchored in the broader field of geomorphological studies on the environmental imprint of warfare.Using high-resolution airborne LiDAR data covering the entire Reims fortification belt, this study aims to (1) analyze the morphological structures resulting from the hybridization of topography and fortification design, (2) investigate the morphogenesis of these war-related anthropogenic landforms to decode the « palimpsest » of the current landscape, and (3) assess their multifaceted legacy— geomorpological, biogeographical, historical, architectural, military, and cultural—with implications for heritage conservation, ecological dynamics, and environmental risk assessment. These contrasting territorial trajectories—ranging from ruin and reforestation to abandonment, preservation, or museographic valorization—reflect the diverse outcomes of military landform integration into peri-urban environments.The complexity of these artificial terrains calls for an interdisciplinary GIS-based approach combining geomorphology with archaeology, history, military and historical geography, geo-history, biogeography, and spatial planning, to explore past, present, and potential future landscape transformations.This research situates war landforms within anthropogeomorphology, where war is considered a powerful shaping force of contemporary landscapes. It also contributes to the recognition of these inherited reliefs as geoheritage objects—carrying scientific, historical, and ecological value—and calls for their inclusion in landform classification frameworks, as well as in heritage management policies and strategies addressing the long-term environmental impacts of conflict-altered terrains, particularly in post-conflict and rapidly urbanizing areas.