Fire Regime Analysis

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Fire regime is defined as the kind of fire activity or pattern of fire that generally characterize a given area. A fire regime analysis helps to evaluate ecological elements of wildfire. Combinations of components can be evaluated to identify areas on the landscape that are fire driven and fire dependant.

Fire Regime Analysis Components

  1. Fire frequency
    The number of fires that occur per unit time and area Fire season
    The period(s) of the year during which fires start and spread sufficient to warrant organized fire suppression
  2. Fire size
    The total area burned and size class distribution for a given area
  3. Fire severity
    The combined ground and above ground effects resulting from smouldering and flaming combustion on either a wildfire or prescribed fire site as manifested in various fire behavior characteristics (i.e., fire intensity, flame height and length, residence and burnout-times, etc.), this is inferred after-the-fact from the fire impact(s).
  4. Fire intensity
    The rate of heat energy release in kilowatts per meter. Determines fire effects and difficulty of control
  5. Fire type
    The class of wildland fire based on the fuel layer(s) involved in the combustion process (ground, surface, and crown).
  6. Burn Probability
    The probability, as expressed by a percentage, that a given area of flammable fuel will burn in a given period of time.

The following figure demonstrates an example of a fire regime analysis output identifying areas on the landscape where fire may have varying levels of ecological benefit. A link between a wildfire threat assessment and fire regime analysis is useful in determining the level and location of ecological constraints and benefit. A clear scope and understanding of objectives and outputs are required to best determine which combinations and number of components a person wishes to include in the fire regime analysis process.

Fire regime
  • Ecological Benefit (severe constraints): Fire is not desired
  • Ecological Benefit (some constraints): Fire is restricted
  • Ecological Benefit (no contraints): Fire is desired
  • No Ecological Benefit: Fire is not restricted


Updated: Apr 27, 2004