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these models represent easily differentiated fuel types with different expected fire
behavior and fire effects.
In 1972, Rothermel introduced 11 “fire behavior fuel models” as inputs for his
work with mathematical fire spread modeling (Rothermel
1972
). In 1976, Albini
added two more fire behavior fuel models (Albini
1976
). This set was further refined
and codified by Anderson in 1982 (Anderson
1982
). Since that time most wildland
fire professionals in the U.S. have been familiar with the 13 Anderson fuel models
and they are still the basis of many computerized fire models, as well as central to
mapping, planning, and even firefighting efforts. Figure
3.2
showsamapofthe13
Anderson Fire Behavior Fuel Models (Fig.
3.2
).
These 13 standard models include categories such as model 1 (short grass),
model 4 (chaparral), and model 13 (heavy logging slash). Each of the 13 models
has assigned values for the amount of available fuels in tons per acre and the depths
of those fuels. Those fuels are further divided into expected amounts of fuels in each
of three size classes of dead fuels as well as the amount of live fuels. Additionally,
each fuel model has an associated level of fuel moisture that is anticipated to extin-
guish fire in that fuel model. These 13 models greatly simplify the mathematical
calculations necessary in developing predictive models of fire spread and behavior,
as trying to model the infinite variety of fuels on the ground is prohibitive.
These original 13 fire behavior fuel models were intended to provide a com-
plete set of references to which the fuels in any forest or grassland patch could be
assigned. These models were also intended to help predict fire behavior during the
severe conditions associated with the peak of fire season. Therefore, each model is
parameterized to account for uniformly low fuel moistures. However, many contem-
porary uses for the fuel models are intended to predict fire behavior in other wetter
and cooler conditions, such as the burning conditions when many prescribed fires
are ignited.
Fig. 3.2
LANDFIRE data mapping the original 13 standard fire behavior fuel models for the State
of Washington. Fire behavior fuel models represent distinct distributions of fuel loading found
among surface fuel components (live and dead), size classes, and fuel types (Graphics by Jacob
Lesser)
