Other Taxonomic Groupings: Subkingdom : Tracheobionta
Division : Coniferophyta
Species Description: Slash pine is an evergreen conifer that has relatively long needles when compared to other pines. Needles grow in clusters of 2 - 3 and measure approximately 31 cm (12 inches) in length. Cones measure 8-16 cm (3 - 6 inches) long, and are a glossy brown color. Cone scales are thin with fine prickles. Wood is durable and hard, nearly equivalent to that of longleaf pine (Pinus palustrus). It has thick, plate-like bark, an extensive root system, and a moderate taproot. The typical variety grows to heights of 18 - 30.5 m (60-100 feet) and trunks average 61 cm (24 inches) in width (Harlow et al. 1979; Anderson 1988).
Taxonomy of this species is sometimes confusing. While no synonyms of this species are now accepted, the species is divided into 2 varieties based on geographic location and morphological differences. Pinus elliottii var. densa Little and Dorman (south Florida slash pine) is a variety formerly recognized as Pinus densa (Little & Dorman) Gaussen. Pinus elliottii var. elliottii Englem. (Honduras pine) is the typical variety of slash pine formerly recognized as both Pinus caribaea sensu Small, non Morelet and Pinus heterophylla (Ell.) Sudworth.
P. elliottii var. densa, south Florida slash pine, has longer needles and smaller cones than the typical variety of slash pine. In addition, it has somewhat denser wood; a thicker, longer, taproot; and its trunk forks into spreading branches that form a broad, rounded crown (Harlow et al. 1979; Wright and Bailey 1982; Lohrey and Kossuth 1990). This variety only grows to 17 m (56 feet) in height, perhaps as an adaptation to avoiding damage due to high winds during storms and hurricanes (Landers 1991).
Regional Occurrence: P. elliottii var. elliottii occurs on coastal plains from South Carolina to Central Florida, and west to Louisiana.
P. elliottii var. densa occurs from Central Florida through South Florida and the Florida Keys. Slash pine has also been introduced into Kentucky, Virginia and eastern Texas, and now reproduces naturally in these locations.
IRL Distribution: Slash pine occurs on coastal plains throughout the Indian River Lagoon area, most commonly in freshwater upland areas.
Age, Size, Lifespan: Slash pines may live as long as 200 years. The typical variety grows to 18 - 30.5 m (60-100 feet), while the south Florida slash pine grows to only 17 m (56 feet) in height. Trunk width in both varieties generally measures 61 cm (24 inches) (Harlow et al. 1979; Wright and Bailey 1982; Lohrey and Kossuth 1990).
Abundance: Slash pines are common throughout the Indian River Lagoon system.
Reproduction: Slash pines are monoecious. They often hybridize with other pines such as loblolly pine (P. taeda), sand pine (P. clausa) and longleaf pine (P. palustris). They begin producing cones at approximately 10-15 years of age. The typical variety produces good cone crops every 3 years, while the south Florida variety produce good cone crops every 4 years. It has been estimated that 90% of the winged seeds from slash pines fall within 46 m (150 feet) of the parent tree (Lohrey and Kossuth 1990). Male strobili begin to develop in June. These grow for several weeks, but then enter a dormant state until midwinter. Pollen is shed from January through February. Female strobili develop in late August and become fully developed. Cones mature in September, approximately 20 months after being pollinated. Seedfall occurs in October (Lohrey and Kossuth 1990).
Embryology: Germination occurs within two weeks following seedfall. Slash pine seedlings in their first year are grass-like in appearance. Seedlings of south Florida slash pine have a 2 - 6 year grass stage similar to that of longleaf pines (P. palustris). Grass-stage seedlings develop extensive root systems and root collars (Harlow et al. 1979). Growth is rapid in the first year, with seedlings reaching heights of approximately 41 cm (16 inches).
Salinity: Slash pines typically inhabit freshwater areas, thus tend not to be salt tolerant. They are most common in the pine flatwood areas of uplands.
Diseases: Slash pines are susceptible to two serious diseases: fusiform rust (Cronartium quercuum f. sp. fusiforme) and annosus root rot (Heterobasidion annosum).
Fusiform rust disease primarily affects seedlings and saplings, causing stem galls. When it infects young seedlings, they are typically killed.
Annosus root rot is a fungal disease that infects freshly cut stumps of slash pine, and spreads to other trees by root contact (Langdon and Bennett 1976; Lohrey and Kossuth 1990).
Physical Tolerances: South Florida slash pine is less susceptible to disease and insects than the typical variety. It is also more drought and flood tolerant (Abrahamson 1984; Abrahamson and Hartnett 1990).
Pests: Slash pines are also damaged by insect pests such as the pales weevil (Hylobius pales), the black turpentine beetle (Dendroctonus terebrans), engraver beetles (Ips spp.), pine web worms (Tetralopha robustella) and others.
Trophic Mode: Autotrophic
Competitors: Slash pines are relatively intolerant of shading and competitors, showing decreased growth rates under shaded and crowded conditions (Langdon and Bennett 1976).
Habitats: Slash pines are common on pine flatwoods throughout its range. Common community types include oak-pine, longleaf-slash pine, southern mixed forests, and southern floodplain forests. It grows best on mesic (dry) flatwoods and near pod or stream margins, but also grows well in poorly drained soils, or in areas that are flooded from time to time (Lohrey and Kossuth 1990). However, seeds will become established in flooded areas (Hebb and Clewell 1976).
Associated Species: Slash pine associates are varied. Plant associates include other canopy trees such as live oak (Quercus virginiana), and cabbage palm (Sabal palmetto); and understory plants such as bluestems (Andropogon spp.), saw palmetto (Serenoa repens) and gallbery (Ilex glabra). Animals associated with slash pines include species that utilize it for protection and cover, as well as those that consume it. Seeds of this tree are eaten by birds and small mammals. Cattle and deer browse its seedlings (Lohrey and Kossuth 1990). Some birds such as the bald eagle and the endangered red-cockaded woodpecker nest in slash pines, though the latter species tends to prefer other trees as nesting habitat (Jackson 1971).
Benefit in IRL: Slash pines provide habitat and food for birds and small mammals, and are an important component of many natural communities.
Economic Importance: Slash pines are an important source of timber in the U.S. Its strong, heavy wood is used for construction. Due to its high resin content, it is useful for producing poles, railroad ties, pilings, turpentine, and rosin (McCulley 1950; Wade 1983; Duncan and Duncan 1988; McCune 1988; Lohrey and Kossuth 1990).
References: Abrahamson, W.G. 1984. Species response to fire on the Florida Lake Wales Ridge. American Journal of Botany. 71(1): 35-43.
Abrahamson, W.G. and D.C. Hartnett. 1990. Pine flatwoods and dry prairies. In: Myers, R.L. and J.J. Ewel, eds. Ecosystems of Florida. University of Central Florida Press, Orlando, FL. pp. 103-149.
Anderson, R. 1988. Guide to Florida trees. Winner Enterprises, USA. 68 pp. ISBN 0-932855-20-2.
Breininger, D.R. and R.B. Smith. 1992. Relationships between fire and bird density in coastal scrub and slash pine flatwoods in Florida. American Midland Naturalist. 127(2):223-240.
Duncan, W.H. and M.B. Duncan. 1988. Trees of the southeastern United States. University of Georgia Press, Athens, GA. 322 pp. Eyre, F.H., ed. 1980. Forest cover types of the United States and Canada. Society of American Foresters, Washington, D.C. 148 pp.
Harlow, W.M., E.S. Harrar, S. Ellwood, F.M. White. 1979. Textbook of dendrology. 6th edition. McGraw-Hill, Inc. New York, NY. 510 pp.
Hebb, E.A. and A.F. Clewell. 1976. A remnant stand of old-growth slash pine in the Florida panhandle. Bulletin of the Torrey Botanical Club. 103(1):1-9.
Jackson, J.A. 1971. The evolution, taxonomy, distribution, past populations and current status of the red-cockaded woodpecker. In: Thompson, R.L., ed. The ecology and management of the red-cockaded woodpecker: Proceedings of a symposium. May 26-27, 1971, Folkston, GA. Tall Timbers Research Station, Tallahassee, FL. pp. 4-29.
Landers, J.L. 1991. Disturbance influences on pine traits in the southeastern United States. In: Proceedings, 17th Tall Timbers fire ecology conference; May 18-21, 1989, Tallahassee, FL. Tall Timbers Research Station, Tallahassee, FL. pp. 61-95.
Langdon, O.G. and F. Bennett. 1976. Management of natural stands of slash pine. Res. Pap. SE-147. U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station, Ashville, NC. 12 pp.
Lohrey, R.E. and S.V. Kossuth. 1990. Pinus elliottii Englem. slash pine. In: Burns, R.M. and B.H. Honkala, technical coordinators. Silvics of north America. Volume 1. Conifers. Agricultural Handb. 654. U.S. Department of Agriculture, Forest Service, Washington, D.C. pp. 338-347. McCune, B. 1988. Ecological diversity in North American pines. American Journal of Botany. 75(3):353-368.
McCulley, R.D. 1950. Management of natural slash pine stands in the flatwoods of south Florida and north Florida. circular No. 845. U.S. Department of Agriculture, Washington, D.C. 57 pp. Monk, C.D. 1968. Successional and environmental relationships of the forest vegetation of north central Florida. American Midland Naturalist. 79(2): 441-457.
Wade, D.D. 1983. Fire management in the slash pine ecosystem. In: Proceedings of the managed slash pine ecosystem, 1981, Gainesville, FL. University of Florida, School of Forest Resources and Conservation, Gainesville, FL. pp. 203-227; 290-294; 301.
Wright, H.A. and A.W. Bailey. 1982. Fire ecology: United States and southern Canada. John Wiley and Sons, Inc. New York, NY. 501 pp