Concepts and interpreted examples in advanced fuel modeling

Abstract

The basic concepts of fuel modeling were presented in the fuel subsystem of BEHAVE. This report expands on these concepts in an attempt to provide a better understanding of the technical details of constructing sitespecific fire behavior fuel models. The discussion is mathematical. It is aimed at fire managers who are familiar with the fire model and who may be dealing with difficult fuels situations.

Surface fuel litterfall and decomposition in the northern Rocky Mountains, U.S.A.

“…Freshly fallen leaves and needles from trees, shrubs, and herbaceous plants are considered foliage, while all other non-woody material, such as fallen cones, bark scales, lichen, and bud scales, are lumped into a category called other canopy fuels. The woody material is sorted into four diameter classes using definitions required by the fire behavior and effects models (Anderson 1982;Burgan 1987;Fosberg 1970;Reinhardt and Keane 1998;Rothermel 1972). The smallest size class, called twigs, defines 1 hr timelag fuels with diameters less than 3 mm.…”

BehavePlus fire modeling system, version 5.0: Variables

“…(Byram 1959) with adjustments to work with Rothermel's surface fire spread model by (Albini 1976b) Surface fire flame residence time (used to calculate fireline intensity) (Anderson 1969) Direction of maximum spread (Rothermel 1983) using manual vectoring (Rothermel 1983) (Finney 1998) calculations based on Rothermel's wind and slope factors Fire characteristics chart, relationship among rate of spread, heat per unit area, fireline intensity, and flame length (Finney 1998) Spread in direction from ignition point from a point source fire (Andrews 1986) Effective wind speed (Albini 1976b) Wind adjustment factor (Albini and Baughman 1979, Baughman and Albini 1980, Rothermel 1983 Wind speed at 10 m adjusted to 20 ft (Turner and Lawson 1978) 13 standard fire behavior fuel models (Rothermel 1972) 11 fuel models (Albini 1976b) slight revision of the 11 plus two more fuel models (Anderson 1982) fuel model selection guide 40 standard fire behavior fuel models (Scott and Burgan 2005) Custom fire behavior fuel models (Burgan andRothermel 1984, Burgan 1987) Dynamic fuel load transfer (Burgan 1979) (Burgan andRothermel 1984, Andrews 1986) as used in BEHAVE (Scott and Burgan 2005) as used in the 2005 standard fire behavior fuel models Two fuel models, weighted rate of spread (Rothermel 1983) Two fuel models, harmonic mean (Fujioka 1985) Two fuel models, 2-dimensional expected spread (Finney 2003) Palmetto gallberry special case fuel model (Hough and Albini 1978) Western aspen special case fuel model (Brown and Simmerman 1986) (Brown and DeByle 1987) for mortality …”

Fuel reduction in residential and scenic forests: A comparison of three treatments in a western Montana ponderosa pine stand

“…However, the mathematical model underlying BEHAVE is-sensitive to fuel parameters that are very difficult to measure in the field (for example, fuel bed depth). Therefore, custom models must be calibrated by comparison with actual spread rate observations by adjusting model inputs such as bulk density and heat content (Burgan 1987). Because this adjustment is not possible in small treatment units, a method of predicting fire behavior that combines a fuel inventory with a standard fire behavior fuel model (Anderson 1982) must be employed.…”