Historical Fire Regime and Current Condition Class in Zion National Park, Utah (ZION_FRCC)

Zion National Park, Resource Management & Research, GIS Program

Fire Regime Current Condition Class is a qualitative measure describing the degree of departure from historical fire regimes, possibly resulting in alterations of key ecosystem components such as species composition, structural stage, stand age, canopy closure, and fuel loadings. One or more of the following activities may have caused this departure: fire suppression, timber harvesting, livestock grazing, introduction and establishment of non-native plant species, introduced insects or disease, or other management activities. Fire regimes describe historical fire conditions under which vegetation communities have evolved and have been maintained Fire regimes describe the frequency and severity of fire events in vegetation communities. Fire frequency is the average number of years between fires. Severity is the effect of the fire on the dominant overstory vegetation, which can be forest, shrub, or herbaceous. Historical natural fire regime data are not exact reconstructions of historical conditions, being defined as conditions existing before extensive pre-Euro-American settlement (pre-1900), but rather reflect typical fire frequencies and effects that evolved in the absence of fire suppression). Fire frequency and severity measures were used to determine the departure from historical conditions. One or more activities may have caused this departure: fire exclusion, timber harvesting, livestock grazing, introduction and establishment of non-native plant species, introduced insects and disease, or other management activities. Current condition class is a qualitative measure describing the degree of departure from historical fire regimes, possibly resulting in alterations of key ecosystem components such as species composition, structural stage, stand age, canopy closure, and fuel loadings. Data typically shows the degree of departure from historical fire regimes. The classification system includes three current condition classes: 1 - fire regimes are within an historical range, and the risk of losing key ecosystem components is low; 2 -fire regimes have been moderately altered from their historical range and the risk of losing key ecosystem components is moderate; 3 - fire regimes have been significantly altered from their historical range and the risk of losing key ecosystem components is high.