1135 Pinus clausaCommon Names: sand pine, scrub pine Family: Pinaceae (pine Family)
Sand pine is a small, bushy, fast-growing short-needled pine with small, ovulate cones. The needles are 2-3.5 in (5-9 cm) long and borne in bundles of two. The cones are 2-3.5 in (5-9 cm) long, often in clusters, and often persistent on the branches. Sometimes the bark actually grows over persistent cones. This is a bushy tree, with multiple branches and a scrubby look to it. Sand pines rarely exceed 25 ft (7.5 m) in height and 12 in (30 cm) in diameter at breast height. The National Champion sand pine is at the Starkey Wilderness Preserve in Pasco County, Florida, and measures 95 ft (28.5 m) tall with a DBH of 27 in (67.5 cm). It is very rare to find a sand pine even close to this large.
Sand pine is most similar to shortleaf pine (P. echinata) and spruce pine (P. glabra). Sand pine differs from shortleaf pine in having smooth twigs and small branches, versus roughened and scaly twigs and small branches in shortleaf pine. It differs from spruce pine in having rough, flaky trunk bark whose outer layers tend to slough off versus spruce pine's bark that is tight, furrowed, and does not slough off.
There are two varieties of sand pine that differ in cone morphology and response to fire. Pinus clausa var. clausa is the Ocala variety that is characterized by cones that are covered in a wax and do not open, and thus do not release their seeds, until they are heated by fire and the mother tree has burned. The Choctawhatchee variety, P. c. var. immunginata, has cones without the wax that open normally, releasing seeds when they are ripe. Otherwise, the two varieties are very similar and some authors have suggested that they should not be recognized as distinct.
Pinus clausa var. clausa, the Ocala variety of sand pine, occurs naturally along both coasts of the Florida Peninsula from Tampa to Naples on the Gulf Coast and from St. Augustine to Fort Lauderdale on the Atlantic Coast, and in the interior highlands of the peninsula from Clay County to Lake Okeechobee. P. clausa var. immunginata, the Choctawhatchee variety, grows naturally in sand dunes along the northern Gulf Coast (and only a very short distance inland) from Carrabelle, Florida, to Baldwin County, Alabama. Sand pine occurs naturally only in habitats usually referred to as "scrub" or "coastal scrub" or Florida scrub. However, sand pine has been planted on tens (if not hundreds) of thousands of acres (hectares) outside and within its natural range, on dry, well drained soils that formerly supported longleaf (P. palustris) pine savanna, (a.k.a., "sandhills" or "high pine".) Sand pine has escaped cultivation and established itself on dry sites near where it has been planted, and nowadays is likely to be encountered on dry, sandy soils almost anywhere in Florida. Both varieties grow in poor, infertile, sandy soils where few other tree species can survive.
CultureLight: Sand pine occurs naturally in scrub habitats where it is subject to full sun. Commercially, it is grown in plantations in full sun. Moisture: Sand pine, once established, is very drought tolerant. Tiny seedlings, however, require rain or watering for their first year or so. Hardiness: USDA Zones 7 - 10. The natural range of sand pine includes USDA zones 8-9. Propagation: Sand pine is planted from seed.
Sand pine is one of the most important trees grown in the southern U.S. for pulp wood. Commercial plantings are often harvested in less than 20 years after planting. The Ocala National Forest in Central Florida has more than 250,000 acres (101,175 ha) of planted sand pine, grown for, and in cooperation with, the commercial pulp wood industry. On the Ocala, the sand pines are either pulled up, roots and all, or cut off at ground level and shredded into chips on site. The chips are then blown into waiting tractor trailer trucks for delivery to the pulp mills in Jacksonville and Palatka. After clear cutting the sand pines, the Forest Service replants the site with a new crop. The sand pines used in this operation are genetically improved cultivars (selected hybrids between the two sand pine varieties), developed especially for the commercial pulp wood industry.
Sand pine grows naturally in the poorest of sandy soils, and on many sites is the only species of tree that can do so. Planted on better sites, with better soils and more moisture, sand pine grows faster and gets larger.
Before Modern Man (i.e., European settlers) invaded Florida, the Ocala variety of sand pine was restricted to scrub habitats that were characterized by infrequent, but very intense fires that killed most above ground vegetation, including the sand pines. These natural, lightning-caused fires in scrub occurred, on average, every 20-75 years. If the sand pines in a mature, unburned scrub released their seeds under their own canopy, any seedlings that germinated would likely die in the shade of their own mother tree. Instead, sand pine evolved serotinous (wax-covered) cones that would not open until the mother tree was killed by fire. Only then would the seeds be released and a new generation of sand pines born in the ashes of the previous generation. Because of this, Ocala sand pine usually occurred in even-age stands. Compare the sand pine's adaptation to infrequent lightning-caused fires to that of the practically fire-proof longleaf pine (P. palustris), which occurred in habitats that burned naturally every year or two. (The Choctawhatchee variety of sand pine is not dependent on fire to release its seeds, and thus usually grows in mixed-age stands.)
In the last 500 years, Modern Man has disrupted the landscape with towns, plowed fields and roads. Today, the selective pressures that caused Ocala sand pines to retain their seeds until the parent tree died have been reduced and even eliminated in some areas. These days, any "sport" tree that might have a tendency to release its seeds before being killed by fire just might get lucky and have those seeds fall on a road shoulder, the edge of a field, or other disturbed land in full sun. Without a killing fire, such open areas simply did not exist before Man's modifications to the landscape. Trees born from non-serotinous parents might well inherit the same non-serotinous characteristic. As a result, many of the Ocala sand pines found today no longer retain closed cones, especially those in close vicinity to Man's activities. Some modern ecologists, unfamiliar with (or not believing) the ecological literature from decades ago, have suggested that the Ocala sand pine does not differ from the Choctawhatchee sand pine. Maybe not any longer, but it used to!
Steve Christman 3/15/11