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).
II. HABITAT AND
DISTRIBUTION
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.
III. LIFE HISTORY AND POPULATION BIOLOGY
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.
Locomotion:
Sessile.
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). The 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).
IV. PHYSICAL TOLERANCES
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.
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).
Diseases:
Slash pines are susceptible to 2 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).
Pests:
Slash pines are also damaged by insects 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.
V. COMMUNITY ECOLOGY
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).
VI. SPECIAL STATUS
Special Status:
None.
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).
VII. 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.
Report by: K. Hill,
Smithsonian Marine Station
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