Airborne laser scanning for forested landslides investigation in temperate and tropical environments

Landslide hazard and risk have increased over the last decades and pose a significant threat to modern society. Despite remarkable efforts of compiling and updating landslide maps at regional, national or global scales, the number of landslide events is often underestimated, especially in forested areas where the vegetation obscures the geomorphic features indicative of landsliding. The primary objective of this study was to investigate the suitability of an active remote sensing technique, airborne laser scanning (ALS), for mapping and classifying landslides in temperate and tropical forest environments. The methods were developed in two study areas: (1) the Bois Noir area in France (Southern French Alps), (2) the Cameron Highlands in Malaysia (tropical rainforest region). In conclusion, the emergence of ALS for investigating geomorphic processes and activities has improved our ability to map, monitor and model the topographic terrain signature and landslide-induced vegetation anomalies. This study explicitly proved that ALS can be a very important new data source and mapping tool to characterize landslides even in a complex environment. The increased prevalence of modern ALS system and advanced point cloud processing had led the ways to improve future landslide maps and subsequently reduce landslide risk. Given the complexity of the terrain, automating the inventorization will still be challenging in the tropics with extensive anthropogenic activity, and differentiating the vegetative reaction in response to different earth surface processes requires further research. Airborne remote sensing is a critical and supportive tool for better understanding of landslide geomorphology in a changing environment.