Pinus clausa (Chapm. ex Engelm.) Vasey ex Sarg.
Range and Habitat
The native range of sand pine. (From Little, 1971.)
Geographic Range
According to Brendemuehl (1990) :
"Sand pine is one of the minor southern pines with a natural range
limited almost entirely to Florida. The largest sand pine concentration is a
block of the Ocala variety covering about 101 170 ha (250,000 acres) in
north-central Florida, and area often referred to as the "Big Scrub." This
variety of sand pine also grows in a narrow strip along the east coast of
Florida from St. Augustine southward to Fort Lauderdale. On the Gulf Coast
small tracts of Ocala sand pine can be found scattered from a few kilometers
north of Tampa southward to Naples. The less abundant Choctawhatchee variety
is found growing along the coast in western Florida from Apalachicola to
Pensacola and extending westward into Baldwin County, AL. Natural stands of
Choctawhatchee sand pine are most abundant in Okasloosa and Walton Counties,
FL, covering an area of about 40 470 ha (100,000 acres). Scattered stands of
this variety of sand pine can be found 32 to 40 km (20 to 25 mi) inland from
the coast in this section of Florida. Sparse stands of sand pine are also
found on many of Florida's offshore islands."
Climate
According to Brendemuehl (1990) :
"The climate of north-central Florida is characterized by hot summers with
abundant precipitation and mild, rather dry winters. Precipitation varies
from 50 to 75 mm (2 to 3 in) per month from October until April to as much as
200 to 230 mm (8 to 9 in) per month in June, July, and August. About 55
percent of the average rainfall of 1350 mm (53 in) occurs in the 4 months
from June through September. Temperature extremes of -11° and 41° C (12° and 105° F) have been recorded. A frost-free
period of 290 days is normal.
"Choctawhatchee sand pine thrives in western Florida under climatic
conditions that are somewhat different from those of north-central Florida.
Rainfall from December through May averages 100 to 110 mm (4 to 4.5 in) per
month. It is hot and humid from June through September but slightly less so
than in the north-central area. About 43 percent of
the average annual rainfall of 1520 mm (60 in) occurs during this period of
the year. October and November are the driest months, with rainfall averaging
about 75 mm (3 in) per month. Temperature extremes of -17° and 42° C (2° and 107° F) have been recorded. Average
temperature for January is 11° C (52° F) and 27° C (81° F) for July. A frost-free period of 265 days is normal."
Soils and Topography
According to Brendemuehl (1990) :
"Sand pine grows on well-drained to excessively drained, infertile, acid to
strongly acid sandy soils of the order Entisols. This sand is of marine
origin, much of which was deposited in terraces developed during the
Pleistocene epoch.
"Most Ocala sand pine grows in the division of Florida known as the Central
Highlands. Elevations range from less than 6 m (20 ft) above sea level near
Lake George to nearly 61 m (200 ft) in the highest areas of this region.
Numerous lakes dot this area and are indicative of the presence of soluable
limestone not far below the surface. Gentle rolling hills characterize the
terrain. The major soils on which Ocala sand pine grow, in order of
importance, are the Astatula, Paola, and St. Lucie series.
"In west Florida, scattered stands of Choctawhatchee sand pine grow on the
excessively drained soils of the Coastal Lowlands; however, the majority of
such stands are in the division of Florida known as the Western Highlands.
Elevations range from near sea level to nearly 90 m (295 ft) above sea level.
The terrain of this area is typified by long, gentle slopes and broad, nearly
level ridgetops. Sloping to steep hillsides border most of the streams and
small lakes of the area. The waterlevel of the rivers, lakes, and
intermittent ponds of the area fluctuates considerably according to the amount
of rainfall and seepage from the surrounding deep, sandy soils. Soils common
to this region include the Kershaw and Lakeland series".
Forest Associates
According to Brendemuehl (1990) :
"The sand pine scrub or north-central Florida is one of the most distinctive plant communities of the State. Of particular interest is the sharpness of the boundaries with the adjacent sandhill vegetation which is dominated by longleaf pine (Pinus palustris), turkey oak, (Quercus laevis), and pineland threeawn (Aristida stricta). Even-aged Ocala sand pine dominates the overstory, while the understory is composed almost entirely of evergreen shrubs 1.8 to 3.0 m (6 to 10 ft) tall. There is little or no herbaceous groundcover. Shrubs found in this understory include sand live oak (Quercus virginiana var. geminata), myrtle oak, (Q. myrtifolia), chapman oak, (Q. chapmanii), rosemary (Ceratiola ericoides), tree lyonia (Lyonia ferruginea), scrub palmetto (Sabal etonia), saw-palmetto (Serenoa repens), silk bay (Persea borbonia var. humilis), gopher-apple (Chrysobalanus oblongifolius), and ground blueberry (Vaccinium myrsinites). Mats of lichens (Cladonia spp.) are often plentiful on the ground beneath the trees and shrubs.
"The west Florida sand pine scrub is a distinct contrast to that of the north-central area. Here Choctawhatchee sand pine generally grows in uneven-aged stands and invades adjacent forested sites if protected from uncontrolled fire. The understory in these stands is quite sparse. Turkey oak, bluejack oak (Q. incana), sand post oak (Q. stellata var. margaretta), pineland threeawn, and prickly pear (Opuntia spp.) are the most common species of this understory.
"Sand pine is the principal component of the forest cover type Sand Pine (Society of American Foresters Type 69). It may also be found in several additional cover types such as Longleaf Pine (Type 70), Longleaf pine-Scrub Oak (Type 71), and Slash Pine (Type 84).
Habitat Competition
According to Brendemuehl (1990) :
"Sand pine has been rated as being moderatley intolerant of shade and competition, but in its early establishment it is quite tolerant. Overall, it probably is most accurately classed as having intermediate tolerance to shade. Sand pine expresses very little dominance in its usual growth pattern. Sand pine grows and persists in very dense stands of approximately 20,000 to 25,000 trees per hectare (8,000 to 10,000/acre). Seedlings of both varieties can be planted or will become established from seed in the scrub oak-wiregrass rough common to the Florida sandhills and eventually dominate the site. Natural pruning is very slow. Dead lateral branches may persist within a few feet of the ground until the trees are 20 to 25 years old."
Hybrids
According to Brendemuehl (1990) :
"Natural hybridization of sand pine has not been know to occur, but several successful attempts at artificial hybridization have been reported. The most encouraging of these efforts is a cross between Virginia pine (P. virginiana) and the Choctawhatchee variety of sand pine produced at the Institute of Forest Genetics at Placerville, CA, in 1953. Seedlings from this cross were planted in Charles County, MD. At age 10, 94 percent (47 trees) of the hybrid seedlings had survived, with an average height of 5.4 m (17.6 ft). Survival of the Virginia pine controls averaged 84 percent with an average height of 4.8 m (15.6 ft). These results indicate the feasibility of moving sand pine germ plasma into more northerly locations through hybridization with Virginia pine."