Fire regime condition class
n. A classification of the amount that current vegetation or fire regime characteristics have departed from the presumed historical reference conditions.
Fire regime condition class (FRCC) uses three condition classes to describe low departure (FRCC 1), moderate departure (FRCC 2), and high departure (FRCC 3). This departure results from changes to one or more of the following ecological components: vegetation characteristics, including species composition, structural stage, and canopy cover, and spatial fire regime characteristics, including fire frequency and severity (Hann and Bunnell 2001; Schmidt and others 2002; Hardy and others 2001; Hann and others 2004).
The three fire regime condition classes are defined in the Interagency FRCC Guidebook as follows:
Fire Regime Condition Class 1: Fire regimes are within the natural or historical range and risk of losing key ecosystem components is low. Vegetation attributes (composition and structure) are intact and functioning.
Fire Regime Condition Class 2: Fire regimes have been moderately altered. Risk of losing key ecosystem components is moderate. Fire frequencies may have departed by one or more fire intervals (either increased or decreased). This may result in moderate changes in fire and vegetation attributes.
Fire Regime Condition Class 3: Fire regimes have been substantially altered. Risk of losing key ecosystem components is high. Fire frequencies may have departed by multiple fire intervals. This may result in dramatic changes in fire size, fire intensity and severity, and landscape patterns. Vegetation attributes have been substantially altered.