Fuel Models for Predicting Prescribed Fire Behavior 

There are 13 fuels models for predicting prescribed fire behavior identified in Aids to Determining Fuel Models for Estimating Fire Behavior, Hal E. Anderson, NFES 1574.  The fuel models are determined by the fuel bed, that portion of the available fuel which carries the fire.  The fuel models are based on fuels that are normally distributed.  Piles are not included in any of the fuel models because they do not have a characteristic fire spread rate.  These fuel models are the basis of the computer models BEHAVEPLUS and BEHAVE (Remsoft).

 The 13 models are divided into 4 Groups (Grass, Shrub, Timber, Slash).  Again note that piles, wind rows, jackpots and other unnatural fuel arrangements are not included in the 13 models.

 The Grass group consists of;

FM-1 Short grass (typically open land),

FM-2 Timber grass (common to SE)

FM-3 Tall grass (sawgrass, cogon, warm-season native grasses such as bluestem,                                    switchgrass)

 The Shrub group consists of:

 FM-4 includes examples of 6-foot and taller shrub types such as  Chaparral, high pocosin, pine barrens of NJ, jack pine sapling stands

FM-5 includes examples of short brush with large green fuel component (vine maple, alder)

FM-6 Dormant brush (low pocosin, PJ, frost killed gambel oak, some southern hardwood shrub)

FM-7 Southern Rough (galberry-palmetto, wax myrtle, yaupon, fetterbush typically 2-6 feet high – the only shrub group found widely dispersed in the South.

The Timber group consists of:

 FM-8 Closed timber litter (dense stands of shortleaf, virginia pine are examples) where the fine fuels are compacted typically moist and do not carry fire aggressively

FM-9 Timber (pine and hardwood) litter (most common fuel type in upper coastal plains, piedmont, and mountains of SE)

FM-10 Timber litter and understory with large component of dead and down material

 The Slash group consists of:

 FM-11 Light logging slash (up to 11-12 tpa)

FM-12 Medium logging slash (12-35 tpa)

FM-13 Heavy logging slash (36-58 tpa)

 Piles, windrows, and jackpots are not part of any fuel model but rather represent a distinct fuel arrangement.  This is of critical concern when planning smoke emissions from a prescribed burn.

 National Fire Danger Rating System

 National Fire Danger Rating System. NFRDS, fuel models should not be confused with prescribed fire predictive models.  There are 20 NFRDS models that are used primarily for planning wildland fire suppression activities.  NFRDA models are identified by letters.

 Determining BEHAVE Fuel Models

 In addition to NFES 1574 there are a series of photos and keys for determining models.  Caution must be exercised when using pictures to determine fuel model.  Remember, the fuel bed, that part of the available fuel, is what determines the fuel model not the species represented.