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Capabilities

FETM User
Inputs

Fuel Characteristics

Categorize Vegetation on Basis of Fuel Characteristic Classes (FCC)

Once the Analysis Area has been defined, the user must categorize the existing vegetation into a series of Fuel Characteristic Classes (FCC), which describes the vegetation type, structure, and loading, among other attributes.  Each FCC is a comprehensive description of the vegetative matrix, beginning at mineral soil and ending at the top of the canopy.  In FETM, FCCs are described by a set of qualitative and quantitative attributes, including:

Qualitative Attributes  

	Predominant vegetation (for example, grass, Ponderosa pine, etc.)
	Structural stage or age class (for example, bare ground, seedings & saplings, poles)
	Loading class (for example, "typical", low, high)
	Activity class (for example, no activity, thinned, blowdown)

Quantitative Attributes  

	Dead-and-down wood fuel loading by size (for example, 0 to 1/4-inch, 1/4 to one inch, etc.)(tons per acre)
	Duff loading (tons per acre)
	Live herbaceous and live woody shrub loading (tons per acre)
	Fuel bed depth (feet)
	Fuel moisture content (percent)

Stand Characteristics

	Height to the base of the live crown (feet)
	Total stand height (feet)
	Foliage and 1-hour fuel loading (tons per acre)
	Crown bulk density (lbs per cubic foot)
	From a stand list: û Tree species û Diameter (inches) û Density (stems per acre) û Height (feet) û Crown ratio and more

Because of their differing characteristics, each FCC has potentially different fire behavior, different disturbance effects, fuel consumption, and emissions. The process of stratifying an Analysis Area into FCCs is one of the more challenging aspects of FETM, primarily because there is no single "best" way to characterize a geographic area.  This decision is often driven by the data available and the management needs of the analysis, and so is best left to the user's discretion. There is no limit in FETM on the number of FCCs that may be defined, but most Analysis Areas are adequately characterized with fewer than 200 FCCs.