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Items starting with F

Fire frequency

How often fires occur within a given time period in a specified area.

Fire hazard

The overall potential for wildfire in a vegetated ecosystem, often expressed as a condition of fuels on the ground and the probability of ignition. To reduce the fire hazard in an area, managers must deal primarily with the fine fuels on the surface of the forest floor and with the smaller diameter trees growing in the understory of a forest that provide a ladder to the larger, dominant overstory trees.

Fire intensity

The rate at which fuel is consumed and heat is generated.

Fire management plan

A strategic plan that defines a program to manage wildland and prescribed fires and documents the Fire Management Program in the approved land use plan. The plan is supplemented by operational plans such as preparedness plans, pre-planned dispatch plans, prescribed fire plans, and prevention plans.

Fire regime

The characteristics of fire in a given ecosystem, such as the frequency, predictability, intensity, and seasonality of fire. The fire pattern across the landscape, characterized by occurrence, interval, and relative intensity. Fire regimes result from a unique combination of climate and vegetation and exist on a continuum from short-interval, low-intensity fires to long-interval, high-intensity fires.

Fire return interval

The average number of years between successive fires in a designated area.

Fire severity

Denotes the scale at which vegetation and a site are altered or disrupted by fire, from low to high. It is a combination of the degree of fire effects on vegetation and on soil properties.

Fire suppression

The practice of controlling forest and rangeland fires in a safe, economical, and expedient fashion while meeting the natural resource objectives outlined in each national forest or grassland land management plan.

Fire-adapted ecosystem

An arrangement of populations that have made long-term genetic changes in response to the presence of fire in the environment.


Vegetation with characteristics that make it more susceptible to damage from fire, such as thin bark, shallow root systems, or a low-branching habit.