2004
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International Archives of the Photogrammetry, Remote Sensing
Department of Agriculture for forest types of the western
United States were adapted for use with the eastern
deciduous forest communities that occur in Great Smoky
Mountains National Park (Anderson, 1982). Extensive
experience in fire management, long-term observation of fire
behavior in vegetation communities of the park and
familiarity with the Anderson fire fuel classification allowed
NPS fire managers to correlate the 13 Anderson fire fuel
classes with forest communities of the southern Appalachian
Mountains. Classes were assigned based on characteristics
such as the overstory community, the type and density of
understory shrubs and the type and amount of leaf litter.
This information was then used to develop a set of rules for
fuel model classification given the combination of particular
overstory and understory classes of the vegetation database.
Figures 6 and 7 depict overstory and understory vegetation
within a portion of Great Smoky Mountains National Park
corresponding with the Calderwood (CALD) USGS
topographic quadrangle (See location “a” in Fig. 1). Detailed
vegetation classes of both overstory and understory were
collapsed to generalize forest and shrub communities
originally mapped as associations of individual species with
over 170 classes to more general forest types containing
approximately 25 classes. This facilitated the definition of
rules for the assignment of fire fuel model classifications
(Fig. 8). Level 1 rules assigned intersected polygons a whole
number fuel class (0 to 13) according to the spatial
coincidence of general overstory and understory vegetation
types. For example, an intersected polygon consisting of a
dry oak hardwood overstory with no appreciable understory
vegetation was assigned a fuel model class of 8 — Closed
Timber Litter, while a more moist hardwood overstory forest
community coincident with a deciduous shrub understory
was assigned a fuel model 9 — Hardwood Litter (Madden and
Welch 2004).
Calderwood Overstory Vegetation
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Figure 6. A portion of the overstory vegetation in Great
Smoky Mountains National Park corresponding to the USGS
7.5-minute Calderwood topographic quadrangle.
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and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
Level 2 rules further refined the fire fuel classification
system by accounting for the density of mountain laurel
(Kalmia latifolia.) and Rhododendron (Rhododendron spp.).
two prominent broadleaf evergreen shrubs found in the park.
An intersected polygon containing scattered hardwoods in
the overstory and light density mountain laurel shrubs in the
understory would be assigned a Level 2 fuel model class of
6.1, while the same overstory polygon with heavy density
Rhododendron would be assigned a class of 6.6. Fire
managers can thus distinguish both understory type and
density from the assigned fire fuel classes which may prove
useful for determining how to suppress a wild fire or when it
might be appropriate to conduct a prescribed burn (Fig. 9).
Calderwood Understory Vegetation
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Figure 7. A portion of the understory vegetation in Great
Smoky Mountains National Park corresponding to the USGS
7.5-minute Calderwood topographic quadrangle.
| GIS/Cartographic Model to Produce Fuel Class May
1
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|
A =
Overstory Vegetation
Rerlass
Generalized
Ouerstory Veg
Understory-Veg
Union
Combined
Overstory/Understory Veg
Rule-Based! Recloss
Fuel Class Map
Figure 8. A schematic diagram of the GIS cartographic
model used to produce the fuel class data sets.