KUCHLER TYPE FIRE ECOLOGY AND MANAGEMENT
KUCHLER TYPE: Southern mixed forest



FUELS, FLAMMABILITY, AND FIRE OCCURRENCE : 
The southeastern United States has one of the highest-known incidences
of thunderstorms in North America, and lightning-caused fires are very
common [8].  Some traits of southern pines related to fuel loading and
fire resistance have been listed [11].

Along the coast from Virgina to Texas, there are thousands of square
miles of land without a natural firebreak.  Firebreaks occur more
inland, where historic fire frequencies were probably lower than in
coastal regions.  During early European settlement, accounts describe
Native Americans using fire during fall and winter to drive game
animals.  This could be done once a year in most areas because enough
fuels accumulated in one year to carry fire.  Along the Coastal Plains,
fuels did not accumulate due to annual summer lightning fires, and
effects of burning by early Native Americans were probably negligible
[19].

Studies in longleaf pine savannas show that fires are usually low
intensity surface fires and rarely reach the crown.  Longleaf pine
needles are highly flammable, and areas with more and larger trees
usually burn hot if litter has accumulated [15].  More than 100 years
ago, the fire maintained longleaf pine savannas had an average fire
frequency of 1 to 3 years.  In areas of slightly lower fire frequency
(5-10 years) mixed pine savannas and woodlands dominated [19].


FIRE EFFECTS ON SITE : 
Burned soils in longleaf pine forests show higher average temperatures
than soils in unburned areas.  Soil moisture is as much as 50 percent
lower on burned sites; with repeated burning, water-absorbing ability of
longleaf soils decreases from 50 to 80 percent.  Some studies report
that organic matter and nitrogen may also be lost with frequent fire on
abandoned old fields.  Other reports show that organic matter and
nitrogen may increase after fire in virgin forests.  This could be due
to an increase in leguminous species and charcoal deposition following
fire.  These differences may be accounted for by comparing differences
in species composition and biomass between oldfield and virgin forest
communities [6].  Detailed effects of fires on soil nutrients in Coastal
Plain forests and their subsequent effects on vegetation have been
listed for Coastal Plain forests [4].


FIRE EFFECTS ON VEGETATION : 
Fire played a major role in determining presettlement vegetation.  Its
effects on vegetation depend on soil moisture and topography.  Longleaf
pine is the only tree in this region whose seedlings are adapted to
survive fire [19].  Most longleaf pine growth during the first 5 years
is concentrated in the roots, which enables it to survive even when the
leaves are consumed by fire [20].  Even then few seedlings may escape
fire [22], but in virgin old-growth stands, one surviving seedling every
5 to 10 years could be enough to maintain a fully stocked stand [19].
Hot fires due to heavy needle litter accumulation can kill longleaf
seedlings [21].  Longleaf pine perpetuates in pure stands when burned
during winter every 3 to 4 years.  Associated pines (loblolly,
shortleaf, and slash) are more adapted to fire cycles of 10 to 15 years
[6].

Slash pine is highly susceptible to fire during its first 2 years and
vulnerable throughout the seedling stage [12,20,21].  After 10 to 12
years it can survive winter fires that do not crown.  If less than 40
percent of its crown is scorched, slash pine growth may be enhanced by
fire.  The south Florida variety is more resistant than the typical
variety [20].

Loblolly pine is not fire tolerant during its first 10 years, but mature
trees are relatively resistant [2,20].  Mature trees with thick bark can
survive low- to medium-severity fires [18].  After loblolly pines have
reached 2 to 4 inches (5-10 cm) in diameter, they can be burned in
winter every 5 to 10 years, which tends to suppress hardwoods [20].

Fire has the following effects on additional canopy dominant species (as
listed by Kuchler):  American beech is fire-intolerant.  It can sprout
following fire, but is susceptible to decay [3,16].  Sweetgum too is
damaged by fire, opening it up to decay.  It is more susceptible to
summer fires than winter fires, but it does sprout following fire [9].
Southern magnolia is usually top-killed by fire, but can sprout [14].
Because of its thin bark, laurel oak is usually top-killed by light
ground fires, but can sprout [13].  White oak needs periodic fire to
perpetuate because it is shade intolerant.  It is moderately resistant
to fire and can sprout [17].

Important understory species in longleaf pine and slash pine stands,
saw-palmetto and inkberry, are highly flammable.  If not burned during
winter every 3 years, fuel loading of these species can lead to fires
severe enough to kill both the understory and overstory [12].

For more detailed information on fire's effects, refer to species
write-ups in the FEIS database.

Some vegetational patterns related to fire frequency in presettlement
southern mixed forests were as follows:  On dry, upland sites frequent
fires maintained longleaf pine savannas.  Turkey oak was also present in
these stands.  Fire may have been less frequent on dry sandhill sites
because of dissected topography and sparse fuels.  As moisture
increased, longleaf pine occurred with slash pine, bluejack oak,
blackjack oak, and post oak.  Shortleaf and loblolly pines may have also
been present.  Pond pine occurred on moist sites where oaks were absent.
Where fires were less frequent, longleaf pine and red oak dominated on
dry sites.  On moist sites longleaf pine was less prevalent; slash,
loblolly, and shorleaf pines were more likely to occur with oaks.
Beech-dominated stands probably occurred where areas were isolated from
fire [19].


FIRE EFFECTS ON RESOURCE MANAGEMENT : 
The mesic, species-rich longleaf pine types, which need fire every 1 to
3 years, are in danger of extirpation [19].  With the exclusion of fire
in recent decades, longleaf pine stands have been replaced with slash
and loblolly pines.  If not for intensive timber production and
prescribed burning in the Southeast, all pine species would be a small
part of the climax forest. Prescribed burns are an effective way of
maintaining pine forests and of reducing severe wildfire hazards in this
region [20].

Fire promotes palatable grasses and forbs under longleaf pine forests
for livestock grazing and wildlife [12].


FIRE USE CONSIDERATIONS : 
Fire can be used to control brown spot disease, to which longleaf pine is
very susceptible [20].


FIRE MANAGEMENT CONSIDERATIONS : 
On outer terraces of Coastal Plains, slopes greater than 15 degrees
serve as effective fire breaks in longleaf pine savannas.  Fires in
these areas usually originate on the upland flats and not in the
bottomlands [19].


REHABILITATION OF SITES FOLLOWING WILDFIRE : 
NO-ENTRY

Related categories for Kuchler Type: Southern mixed forest