FIRE ECOLOGY
SPECIES: Pinus palustris | Longleaf Pine 



FIRE ECOLOGY OR ADAPTATIONS : 
Longleaf pine is classified as fire-resistant [10,36].  It is ideally
suited to a high-frequency, low-severity surface fire regime.  The
natural fire interval is every year to every 5 to 10 years [44].  Most
natural fires are caused by lightning and occur in late spring and
summer [37,44].

Longleaf pine has many adaptations to fire.  The grass-stage seedling is
resistant to fire.  If top-killed, it sprouts from the root collar.
Once the terminal bud develops, it is protected by a moist, dense tuft
of needles.  As the tuft burns towards the bud from the needle tips,
water is vaporized.  The steam reflects heat away from the bud and
extinguishes the fire [37,38].  The bud also has scales for protection
and a silvery pubescence that probably reflects heat [29,37]. 

During the grass-stage, the seedling invests heavily in a taproot and in
root collar size.  When height growth is initiated, often the year after
a fire, the seedling uses its stored reserves to quickly grow a straight
stem with no branches.  After one growing season, the terminal bud is
usually above the level of the next surface fire [37,38].

The bark becomes thick with age and insulates the cambium from heat.
The scaly bark dissipates heat by flaking off as it burns [37,38].

In addition to fire resistant adaptations, longleaf pine has a pyrogenic
strategy.  Spring and summer fires are beneficial because they reduce
competition and expose the mineral soil necessary for seed germination
in the fall.  Long, resin-filled needles have short persistence and form
a highly flammable, well-aerated litter.  Resin is also concentrated in
the bole and roots of older trees and snags.  These trees act as
lightning receptors.  A smoldering tree can ignite the ground several
days or weeks later when the ground litter has dried out.  Longleaf
pine communities often have a grass understory that readily ignites.
[28,37,43].  Because of open stands and high and open crowns, crown
fires are rare [43].


POSTFIRE REGENERATION STRATEGY : 
   Crown-stored residual colonizer; short-viability seed in on-site cones
   off-site colonizer; seed carried by wind; postfire years one and two

Related categories for Species: Pinus palustris | Longleaf Pine