BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Pinus clausa | Sand Pine 



GENERAL BOTANICAL CHARACTERISTICS : 
Sand pine is a small, narrow, evergreen conifer with a dense, pointed
crown of highly divided branches.  Sand pines grown on productive sites
attain heights of 66 feet (20 m) and diameters of 18 to 20 inches (45-50
cm), but smaller trees are more common [1,16].  Sand pine rarely reaches
100 years in age.  Individuals can be gnarled, leaning, or stunted.  The
thin gray bark is fibrous and brittle, and cones have short, stout
spines [10].  Seedlings grown in sand have a fine root system with
numerous laterals.


RAUNKIAER LIFE FORM : 
   Phanerophyte (mesophanerophyte)


REGENERATION PROCESSES : 
Seed production and dissemination:  Sand pine is monoecious.  Trees can
begin producing cones at 5 years of age [1] and can form two or three
whorls of cones per year [7,12].  The Ocala variety produces an abundant
cone crop almost every year.  Ocala cones are predominantly serotinous,
although 20 percent or more of the individuals in Ocala stands may have
at least some open cones [16].  The closed cones persist in the crown
for 10 or more years [10].  The Choctawhatchee variety has mostly
nonserotinous cones that open when mature.  A good cone crop occurs
every 4 to 6 years.  The winged seeds of both varieties are dispersed
short distances by wind [1,10].

Seedling development:  Seed viability in closed cones decreases with
cone age and is only 10 to 20 percent in 5-year-old cones.  Epigeal
germination occurs at any time of year but is rare in the heat of the
summer [1].  Seedlings are killed by ground temperatures of 125 degrees
Fahrenheit (52 deg C) [9].  They are also destroyed by ants and birds.
Ocala sand pine grows 15 to 18 inches (38-46 cm) in the first year while
Choctawhatchee sand pine grows only 10 to 15 inches (25-38 cm) [1,21].
Sand pine growth is more influenced by nutrient deficiency of the soil
than by water deficiency [16].  Ocala sand pine grows in dense even-aged
stands while Choctawhatchee sand pine grows in more open, uneven-aged
stands with scattered seedlings and saplings in openings [12].

Vegetative reproduction:  Choctawhatchee sand pine seedlings have basal
branches which may replace the main stem if it is top-killed [1].




SITE CHARACTERISTICS : 
Sand pine grows on xeric sand ridges that are thought to be former
Pleistocene dunes and shorelines.  The terrain is hilly to gently
rolling.  Ocala sand pine ranges in elevation from 20 feet (6 m) to 200
feet (61 m), and Choctawhatchee sand pine from near sea level to 295
feet (90 m) [1].  Sand pine grows in well-drained to excessively
drained, acidic sandy soils of marine origin.  These soils are primarily
Entisols derived from quartz sand [1].

The understory associated shrubs of the Ocala variety include myrtle oak
(Quercus myrtifolia), Chapman's oak (Q. chapmanii), sand live oak (Q.
virginiana var. germinata), scrub oak (Q. inopina), rusty lyonia (Lyonia
ferruginea), Florida rosemary (Ceratiola ericoides), scrub palmetto
(Sabal etonia), saw-palmetto (Serenoa repens), silk bay (Persea borbonia
var. humilis), ground blueberry (Vaccinium myrsinites), gopher-apple
(Chrysobalanus oblongifolius), beakrush (Rhynchospora megalocarpa), and
palafoxia (palafoxia feayi).  Many of these shrubs are evergreen or
nearly evergreen.  There is little or no herbaceous ground cover [1,16].
(Also see SAF Cover Types).

The understory of Choctawhatchee sand pine stands is sparse and includes
turkey oak (Q. laevis), bluejack oak (Q. incana), sand post oak (Q.
stellata var. margaretta), pineland threeawn (Aristida stricta), and
prickly pear (Opuntia spp.) [1].


SUCCESSIONAL STATUS : 
Sand pine is moderately intolerant of competition and intermediate in
shade tolerance [1,16].  It will establish in and eventually dominate
scrub oak communities.  Sand pine will invade longleaf pine (Pinus
palustris) forests in the absence of fire.  Sand pine scrub vegetation,
in which sand pine grows in very dense, even-aged stands of 8,000 to
10,000 trees per acre (20,000-25,000/ha), is considered a fire-climax
community [9].  If fire occurs once every 20 to 60 years in sand pine
stands, the vegetation community will not change.  In the absence of
fire, a xeric hardwood forest of oak and hickory will succeed sand pine.
If there is frequent fire, oak scrub or slash pine (P. ellottii) will
replace sand pine [1,5,9,15,16].


SEASONAL DEVELOPMENT : 
Flower buds form in early summer and become visible by early autumn.
The Ocala variety usually begins shedding pollen in mid-November but can
begin shedding a month later.  The Choctawhatchee variety usually begins
shedding pollen in late January but can begin anytime from late December
to mid-March.  Cones mature by the end of the second year [1,7,10].

Related categories for Species: Pinus clausa | Sand Pine