A Novel Spectral–Spatial Methodology for Hierarchical Fuel Type Mapping in Mediterranean Ecosystems Using Sentinel-2 Timeseries and Auxiliary Thematic Data

Wildland fuel distribution and characteristics are critical components for the development of a national integrated wildfire management strategy. This study presents a methodological framework for the mapping of fuels in Mediterranean ecosystems in the different levels of a new fuel hierarchical classification scheme, using a spectral–spatial approach based on Sentinel-2 timeseries and auxiliary thematic maps. Furthermore, in the context of this research, a novel approach is proposed for separating Mediterranean shrubland vegetation into three broad height categories, using Sentinel-2 images, landscape variables, and climatic data. Two areas in Greece, namely Attica and Euboea, with major wildfire events over the past 3 years were selected as the study areas. The mapping methodology was designed to consist of three complementary mapping processes, each for the identification of specific types of fuels (i.e., urban, agricultural, and vegetation). The results are validated in a two-step approach for different levels of the classification scheme. The results for the first level display an overall accuracy of 88% and kappa of 0.84, while for the second level, overall accuracy was 71.64% and kappa was 0.68. Our research demonstrates the capacity to map fuel types with promising accuracy at different depths, highlighting a viable method that can be potentially exploited for the large-scale fuel mapping of Mediterranean biomes at a national level.