Burn Severity Definition

Terminology commonly used when discussing fire behavior and fire effects is often inconsistently and interchangeably applied. Inconsistent definitions associated with risk, hazard, and severity confound our ability to characterize and communicate postfire effects and their implications to resource and cultural values (Hardy 2005). Data and information developed by this project are intended to primarily characterize fire effects in aboveground biomass. Despite significant variation in published definitions of burn severity and fire severity (Lentile and others 2006), postfire effects in aboveground biomass have been described using both terms. The term burn severity as it applies to this project is best represented by the definition for fire severity in the NWCG Glossary of Wildland Fire Terminology, stated as the “Degree to which a site has been altered or disrupted by fire; loosely, a product of fire intensity and residence time” (NWCG 2005). The following additional statements have been adopted to further clarify the nature of the products developed by this project:

• Burn severity is a composite of first and second order fire effects on biomass;
• Occurs on a gradient or scale (ordinal);
• Occurs within a fire perimeter;
• Occurs within landcover strata;
• Longer term effects are complicated by variables that this project is not characterizing;
• Severity is mapable;
• Remote sensing provides a measurement framework.