Forest Fire Hazard Mapping in the La Peyne Area, France
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Due to their potentially severe social and ecological effects, wildfires are an important topic for research, both in terms of their spreading behavior, and their chance of ignition. The primary research objective is to create a fire hazard map for a Mediterranean site prone to forest fires. Combining literature, fieldwork, remotely sensed imagery and GIS software, this research focuses on creating four main components of such a map, using a combination of both in-field measurements and remotely sensed data: 1. Risk caused by vegetation 2. Risk caused by human activity 3. Risk caused by terrain 4. Risk caused by weather Risk caused by vegetation was computed for each of the occurring fuel types encountered in the study area. The highest vegetation risk was shown to be in the pine forest and areas with large amounts of shrubs and ground fuels. The lowest risk values were associated with vegetation mainly consisting of mature trees which, due to their thicker trunks, would be less prone to wildfire ignition and/or spread. Risk caused by human activity was concentrated along the (main) roads, dirt roads and hiking trails. The edges of villages, agricultural lands and parking lots (barbecue areas), indicate locations where sparks or still smoldering material may end up igniting the vegetation. Risk caused by terrain was determined by extracting slope and aspect from an existing digital elevation model. Risk caused by weather was omitted from the combined hazard map, due to poor data applicability on the valleys present in the study area. The final, overall hazard map was created by combining the vegetation, human, and topographical risk maps into one, each with its own weight factor. The most severe hazards are found in the pine forest in the southeastern part of the study area, and to the west and south of the lake, where the vegetation mainly consists of high amounts of shrubs and woody fuel / litter. The immediate surroundings of buildings, parking lots and agricultural areas pose a strong increase in fire hazard due to increased risk of ignition from glowing embers or coals (barbecue, campfires). The combination of several individual influences on fire hazard, into a single map, can provide insights into relationships between the factors themselves, and how they reinforce or perhaps weaken each other. Since overall fire hazard is ultimately determined by multiple factors, changing one of them could very well lead to the desired reduction of wildfires. Object-orientated classification methods may help in classifying man-made structure from either satellite imagery or (existing) topographic maps. More insight is needed on the actual influence of aspect on overall fire risk. Maybe in future, a direct feed from meteorological systems can be used as an overlay on top of the combined hazard map, allowing areas that reach a certain hazard-threshold to be identified quicker and more accurately.