NFDRS model	Model description	Fuel load (Mg/ha)
A	Western grassland vegetated by annual grasses and forbs	1.6
B	Mature, dense fields of brush at least 2 m high	51.6
C	Open pine stands with perennial grasses and forbs	10.8
D	Palmetto - gallberry understory and pine overstory	19.1
E	Leaf fall for hardwood and mixed hardwood - conifer types	10.6
F	Mature, closed chamise stands and oakbrush field of Arizona, Utah, and Colorado	37.0
G	Dense conifer stands with heavy accumulation of litter and downed woody material	61.6
H	Healthy stands of short-needled conifers with sparse undergrowth and thin layer of ground fuels	21.3
I	Clearcut conifer slash: total loading > 56030 kg/ha for materials < 15.25 cm diam.	130.0
J	Clearcuts and heavily thinned conifer stands: loading < 56030 kg/ha for material <15.25 cm diam.	71.7
K	Slash fuels from light thinning and partial cuts in conifer stands; loading < 33617 kg/ha	26.9
L	Western grassland vegetated by perennial grasses	2.2
N	Marsh situation where fuel is course and reedlike	15.7
O	Brushlike fuels of the Southeast	45.9
P	Closed, thrifty stands of long-needled southern pines	10.1
Q	Dense stands of Alaskan black spruce: frequent openings filled with usually flammable shrub species	43.3
R	Hardwood areas after the canopies leaf out in the spring	6.7
S	Alaskan and alpine tundra on relatively well-drained sites	10.1
T	Sagebrush - grass types of the Great Basin and the Intermountain West	12.3
U	Closed stands of western long-needled pines	15.7