Why Map Fire Severity
Motivation for mapping wildland fire severity (burn severity) comes from three basic areas. Fire Ecology is interested due to the response the ecosystem has in response to the severity of a fire. Federal law and resulting policy direct the management and monitoring of wildland fire as an agent of change in relation to natural and infrastructural resources across the country. Wildland fire also affects the efforts of local land managers as they respond to the impact of wildland fire on resources and infrastructure at a local level.
Fire ecology focuses on wildland fire’s relationship to the ecosystem containing the fire, considering effects on both living and non-living components of the ecosystem. Most wildlands have evolved with fire, requiring periodic blazes to maintain ecosystem health and regeneration. As a result, federal policy acknowledges this relationship by specifying that where possible, wildland fire should be utilized to restore and maintain the natural systems found in fire adapted ecosystems (WFLC, 2014). Additionally, utilization of wildland fire has been found to be one of the most cost effective means for managing these fire adapted ecosystems.
Within the United States, national wildland fire policy is specified in the National Cohesive Wildland Fire Management Strategy (Cohesive Strategy), which outlines the national wildland fire policy set forth by the Wildland Fire Leadership Council (WFLC) in response the Federal Land Assistance, Management and Enhancement (FLAME) Act of 2009. The Cohesive Strategy directs the federal land management agencies to assess the effectiveness of wildland fires in restoring and maintaining ecosystem resiliency (WFLC, 2014), the first of the national goals listed in the Cohesive Strategy. In order to perform this assessment, the Cohesive Strategy calls for the development of more accurate means for identifying and retaining fire history data than is possible with current methods of updating fire history records. The Cohesive Strategy also calls for the assessment of the utilization of wildland fire when implemented as a tool for performing fuel reduction treatments. Lastly, the Cohesive Strategy calls for development of a more accurate means of collecting fire history data will assist in the evaluation of the departure of current fire regime (wildland fire frequency and burn severity) from the historic range of variability. As a result of the Cohesive Strategy, restoration of the current fire regime to historic conditions drives the funding of that enables vegetation treatments which have the ability to reduce potential fire severity and return fire frequency to the historic levels.
At a local level, management of wildland fires includes post fire recovery planning and other management operations which are driven by burn severity and extent. Once a wildland fire has been contained, federal policy stipulates that post fire recovery plans must be completed within 7 days, leaving little time for collecting data, including burn extent and severity. Reliance on satellite data for determining the extent and severity of the may prove problematic in that Landsat satellites will overpass every 16 days. If smoke or clouds persist over the burn, the availability of satellite data will take even longer to allow for the satellite to overpass the fire again. Additional effects a wildland fire that must be considered involve the potential impact that rain events may affect on lands within and around the fire. These impacts may include flash floods, erosion, and sedimentation of neighboring hydrologic features. Additionally, local managers will need to update local records to reflect the impact the fire is having on the associated ecosystem, updating local geospatial data to reflect the impact of the fire on vegetation and fire history.