Fuels of Southern Wildlands

Fuel is all living and dead plant material that can be ignited by a fire. Fuel characteristics strongly influence fire behavior and the resulting fire effects on ecosystems. Fires vary widely in the kind of fuels that burn (e.g., live vs. dead fuels, surface vs. ground fuels), the total amount of fuels that burn, and the rate or intensity at which these fuels burn. These characteristics of fuel consumption, in turn, determine peak temperatures reached, the duration of heat, and the stratification of heat above and below the soil surface (Miller 1994). The following sections discuss concepts that will help users understand how fuels affect fire behavior.

• Fuel Categories defines ground, surface, ladder, and canopy fuels and explains factors controlling the availability of each fuel type.
• Physical Fuel Properties explains how fuel size, shape, loading, and arrangement combine to influence combustion and fire behavior. Several techniques for measuring fuel loads are also described.
• Chemical Fuel Properties describes how the chemical composition of fuels affects their heat content and flammability.
• Fuel Moistureexplains how fuel moisture determines fuel availability, what controls fuel moisture, defines time-lag classes, and describes several techniques for measuring fuel moisture.
• Fuel Availability and Consumption explains what factors control the availability of both live and dead fuels.
• Plant Flammability discusses species-specific factors that control the flammability of live plants and presents flammability indices for common southern plant species.