Determining the economic damage and losses of wildfires using MODIS remote sensing images

Abstract

The economic evaluation of damage and losses of the areas affected by forest fires requires comprehensive studies covering a wide range of natural resources. The assessment of fire impacts requires the individualized study of each resource, such as timber resources, fruit production and hunting activity, and the analysis of their net value change based on fire intensity and ecosystem resilience. As a consequence, this concept of net value change extends the study beyond an economic valuation, integrating two concepts, the value of the resource and fire behavior. However, field sampling on large fires becomes complex because of the costs involved in field tasks and the time that will elapse before the assessment is available. The incorporation of satellite imagery to the economic valuation of fire impacts provides a new tool of undoubted interest. This paper details the methodology and the results obtained in the economic assessment of two medium (between 200-500ha) and two large fires (more than 500 ha) in the south of Spain. MODIS data were suitable for mapping medium and large fires (more than 200 ha). The advantage of using MODIS satellite images in relation to other remote sensors lies in the free download (zero cost) and temporal resolution. As other studies have shown, the normalized vegetation index was not presented as the best identifier of the burned area. However, RdNBR index allowed us to obtain reliable relationships between its value and the depreciation ratio for each resource due to the differences among resources based on fire intensity. Economic resources valuation and MODIS images (pre and post-fire) can be integrated into Geographic Information System (GIS), in order to obtain, in a geo-referenced way, the economic value per hectare resulting from fire impact. This tool should provide a procedure to help improving fire management and take more appropriate decisions about budget allocation and rehabilitation of areas affected by fires. Given current economic constraints, the use of a geo-referenced tool with free download and regular update (MODIS) allows us to the inclusion of changes, improvements and temporal or spatial adaptations according to the needs of forest managers. The methodological approach for assessing the economic impact of forest fires provided allows the application of this simple and flexible technique to any territory by previous economic valuation of natural resources presented in the interesting area.