FIRE EFFECTS
SPECIES: Pinus elliottii | Slash Pine 



IMMEDIATE FIRE EFFECT ON PLANT : 
One- and two-year-old slash pine are killed by low-severity fire.  After
3 to 4 years, seedlings survive low-severity fire but not
moderate-severity fire.  Ten- to fifteen-foot-tall (3.0-4.6 m) saplings
survive moderate-severity fires.  Once slash pine is 10 to 12 years old,
it survives fire that does not crown [10,24,41,46].

Slash pine is tolerant of crown scorch.  Scorched foliage is replaced by
new shoots.  Slash pine as young as 5 years old may recover from 100
percent crown scorch [6,41].  Slash pine taller than 5 feet (1.5 m)
seldom die if less than 70 percent of the crown is scorched [26].  In
New South Wales, Australia, a fall wildfire burned a slash pine
plantation averaging 20 feet (6.1 m) in height.  The fire crowned in
most areas.  Trees with no green needles, few or no brown needles, and a
drooping apical branch had 31 percent survival, trees with mostly brown
needles and few or no green needles present had 93.8 percent survival,
and trees with clearly visible green needles at the top had 96.9 percent
survival [39].

Slash pine needles were killed instantly when immersed in water at 147
degrees Fahrenheit (64 deg C) but survived 9.5 minutes at 126 degrees
Fahrenheit (52 deg C) [5].

If slash pine bark is thicker than 0.6 inch (1.5 cm), mortality due to
cambium damage is unlikely from a low-severity fire.  In one study,
0.08-inch (0.2 cm) thick bark protected the cambium from externally
applied heat at a temperature of 572 degrees Fahrenheit (300 deg C) for
1 minute.  Bark which was 0.47 inch (1.2 cm) thick protected the cambium
from 1110 degrees Fahrenheit (600 deg C) for 2 minutes [6].


DISCUSSION AND QUALIFICATION OF FIRE EFFECT : 
Seedlings of the south Florida variety are more fire resistant than the
typical slash pine variety but less resistant than longleaf pine
seedlings [46].  In Florida, 2-year-old seedlings of both varieties
averaging 3 feet (0.9 m) in height were burned by wildfire in December.
Twenty-three percent of the south Florida variety burned by headfire and
56 percent burned by backfire survived.  Less than one percent of the
typical variety survived either headfires or backfires.  One-third of
the south Florida slash pine survivors sprouted from dormant buds at or
near the root collar and along the bole.  Root collar sprouts died back
after new needle growth appeared below the fire-killed leader [19].

A cool, prescribed winter fire in a south Florida slash pine stand
killed many older pines, but young pines survived.  Although there was
no outward sign of fire damage, fire may have killed the feeder roots,
and only young, vigorous pines were able to recover [43].


PLANT RESPONSE TO FIRE : 
Slash pine's growth response to fire is variable.  Slash pine damaged by
fire may suffer a short-term reduction in growth, although fires that
result in light or no scorch may actually enhance growth [41].  In the
Georgia Coastal Plain, a 9-year-old stand averaging 24.5 feet (7.5 m) in
height and 3.5 inches (8.9 cm) in d.b.h. was prescribed burned in
February.  In the first postfire growing season, slash pine with 0 to 15
percent crown scorch outgrew the control, pine with 15 to 40 percent
crown scorch was not significantly different in growth from the control,
and pine with more than 40 percent scorch showed reduced growth.  Growth
returned to normal in the second postfire growing season [16].

Severely scorched, 25-year-old slash pine in Georgia, averaging 8 inches
(20 cm) in d.b.h., lost almost a full year's growth in two growing
seasons.  Growth of trees with less than 10 percent crown scorch was
only 85 percent of unburned trees after 2 years [17].  In Louisiana,
annual and bienniel prescibed backfires initiated in a 4-year-old stand
averaging 7.8 feet (2.4 m) in height reduced growth, but trienniel fires
did not.  Whether the fires were in May or March had no effect on growth
[12].

Height growth is slightly more sensitive to needle scorch than diameter
growth.  McCulley [26] reported that height growth loss occurred in
trees with no crown scorch if they were smaller than 7 inches (18 cm) in
d.b.h., but diameter growth loss only occurred in trees with greater
than 30 percent crown scorch.


DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : 
NO-ENTRY


FIRE MANAGEMENT CONSIDERATIONS : 
If a poor seed crop is expected, prescribed burning should be done prior
to seedfall to enhance germination.  Prescribed burning before stand
establishment also reduces fire hazard in young stands.  Prescribed
burning at 3 to 5 year intervals throughout the stand rotation will
facilitate future seedbed preparation, and control but not eradicate
hardwoods.  Hardwoods benefit wildlife and complete eradiction is not
necessary.  At the end of the rotation, successive summer fires can be
used for site preparation [22].  In the southern Florida pine rocklands,
fire every 3 to 7 years has effectively controlled hardwoods [42].

Young slash pine stands should not be burned for the first 5 years or
until the stand is 12 to 15 feet (3.7-4.6 m) tall [22,26,46].  Cattle
can be used to reduce fuel buildup until young pine stands are resistant
to light fire [12,46].

Prescribed winter and spring burning is usually done in pine flatwoods
every 2 to 3 years to increase range grasses for cattle [41].

In the Coastal Plain, prescribed burning before and after thinning
reduced infection by root rot caused by Heterobasidion annosum.  The
fire destroyed the litter that is associated with sporophore development
of the fungus.  A fungal competitor, Trichloderma spp., increased in the
soil after burning and may have contributed to the reduced infection
[9].

Related categories for Species: Pinus elliottii | Slash Pine