FIRE ECOLOGY
SPECIES: Pinus clausa | Sand Pine 



FIRE ECOLOGY OR ADAPTATIONS : 
Sand pine is classified as fire-resistant because it regenerates
profusely through seeds after fire.  Mature trees have a low tolerance
to fire because of thin bark [14].

Sand pine is maintained by infrequent, high-severity fires [1,16,17].
The dense crown canopy of sand pine reduces understory vegetation and
fuel build-up on the ground.  Most understory vegetation is evergreen
which does not produce a thick litter of dry leaves, and there is little
or no grass.  Fire usually stalls out at the outside edge of a sand pine
stand, but if the stand is ignited, a severe fire will occur.  This
delayed pyrogenic strategy results in instant site recapture [10].
Large numbers of seeds are released from serotinous cones and germinate
on the exposed ground.

Sand pine stands usually only burn in the spring when high winds carry
fire into the crowns [5].  In addition, needle water content is at its
lowest and ether content at its highest in the spring [22].  Sustained
hot weather will also make the stand more susceptible to ignition [16].
Highly flammable Spanish moss (Tillandsia usneoides) accumulates on
older sand pine and can be ignited by lightning or can elevate a ground
fire to the crown [9].

Fire intervals of 20 to 60 years maintains even-aged sand pine stands
[16,20].  If more frequent, trees may not be old enough to reproduce.
If less frequent, sand pine becomes senescent and is replaced by oak.

Sand pine communities are often intermixed with longleaf pine
communities which burn every 3 to 8 years.  Adjacent low-severity ground
fires rarely ignite young sand pine stands.  Richardson [20] reported
that scrub allelopathy prevents grass and pine regeneration in sand pine
communities and along the borders.  Grasses and pine seedlings would
otherwise provide fuel for surface fires.

Choctawhatchee sand pine usually grows in areas free of fire.
Open-coned forms of the Ocala variety also invade and establish in areas
with no fire.  Open-coned stand reestablishment after fire is dependent
on trees located near the periphery of the burn.  The degree of serotiny
in Ocala and Choctawhatchee stands is probably a function of fire
history [16].  Open-coned stands may have a history of no fire or
frequent low-severity ground fires, whereas close-coned stands may have
a history of infrequent but high-severity crown fires [12].


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

Related categories for Species: Pinus clausa | Sand Pine