Live oak hybridizes with dwarf live oak, swamp live oak, and other species
Live oak remains foliated nearly year-round, dropping
its leaves and regenerating new growth within a few weeks during spring.
No consensus has been agreed upon regarding the
taxonomic status of Q. virginiana. Some researchers recognize 3 separate
species, while others recognize varieties rather than distinct species (Vines
1960; Little 1979; Harms 1990).
II. HABITAT AND
Live oak is an important component of maritime
hammocks and scrub lands throughout its range from Virginia to Florida,
including the Florida Keys. Westward, it ranges into Texas, where it is found to
the east end of the Brazos River. West of the Brazos, Texas live oak (q.v.
var. fusiformis) dominates (Simpson 1988).
The range of live oak corresponds to southeastern
maritime strand communities (Oosting 1954) which lie southward of the 5.5°
C (41.9° F) isotherm for average daily minimum
temperatures in the coldest month of the year, typically January (Johnson and
Live oak is widely distributed throughout the
Indian River Lagoon system in maritime hammocks bordering coastal and inland
wetlands. It is typically found in live oak-sea oats communities, live oak-slash
pine communities, sand pine scrub communities, and the uplands of oak-pine
forests. Live oak is somewhat more common in the northern portion of the lagoon
around Cape Canaveral. South of this area, live oak and its associated species
are gradually replaced by tropical shrubs (Myers and Ewel 1990).
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Live oak is fast-growing under optimal conditions.
Seedlings may reach 1.2 m (4 feet) in height within the first year, but growth
rates taper off as age of the tree increases (Harlow et al 1979; Haller 1992).
70 year old trees may have trunks that measure as much as 54 inches in diameter
(Van Dersal 1938).
Live oak is generally abundant throughout its
range, and is often the dominant species in maritime hammocks. In the Indian
River Lagoon, it is highly abundant on scrub lands, maritime hammocks, and
upland forests. It is somewhat more abundant in areas of the lagoon north of
Q. virginiana is monoecious. Small flowers
are produced in spring during the growth period for new leaves. Pollen is
dispersed by winds, generally during early April. Acorns are produced in
abundance the following September (Harms 1990). Acorns generally fall to the
ground during December, and are dispersed by animals.
Live oak sprouts from root collars and from roots.
Dense clonal colonies sometimes result from this mode of reproduction, and have
been observed up to 20 m (66 feet) in diameter.
Germination occurs shortly after seedfall in warm,
IV. PHYSICAL TOLERANCES
Live oak is extremely susceptible to freeze damage
(Harms 1990). Its range thus corresponds to the 5.5°
C isotherm along the east coast of the southern U.S.
Live oak is highly tolerant to salt spray
conditions and often can be found growing where its roots are inundated with sea
water at high tides. However, it does not withstand prolonged periods of
saturation (Vince et al. 1989).
Live oak is able to withstand hurricane force winds
and heavy rains and short periods of flooding, though not prolonged inundation
(Vince et al. 1989). It is also tolerant of salt spray and high soil salinity.
Diseases of live oak include live oak decline,
a wilt disease caused by fungus that is a serious problem in Texas live oak, and
perhaps other species as well. A defoliating disease called leaf blister, is
also a problem for live oak species. Heartwood decay is able to infect trees,
but typically, the sapwood in live oak is so strong that infected trees often
remain standing (Harms 1990). Additionally, gall wasps may also colonize live
oak, but apparently have little effect upon health of colonized trees (Haller
V. COMMUNITY ECOLOGY
Live oak is the dominant plant climax species in
coastal forests in the northern portion of its range (Helm et al. 1991). It
withstands competition due to its extreme salt tolerance and tolerance to shade.
Live oak grows well in moist to dry sites in scrub
and maritime hammocks of the southeastern United States. It also shows good
growth in clay and alluvial soils (Harms 1990).
Live oak provides cover and shade for a wide
variety of coastal species of birds and mammals. Acorns of live oak are an
important food source for the Florida scrub jay, mallards, sapsuckers, wild
turkey, black bear, squirrels and white-tail deer. Scrub jays, a threatened
species, nest in live oak (Woolfenden 1973).
Epiphytes of live oak include mistletoe (Phoradendron
spp.), ball moss and Spanish moss (Tillandsia usneoides). Spanish moss
can be especially populous in live oak (Haller 1992).
VI. SPECIAL STATUS
Benefit in IRL:
Live oak is beneficial as habitat and for providing
shade to many birds and small mammals. It is especially important to the Florida
scrub jay as nesting habitat.
Live oak wood is strong and heavy, and has
previously been used in ship building. However, it is now seldom utilized
commercially (Harms 1990).
Harlow, W.M., E.S. Harrar, and F.M. White. 1979.
Textbook of dendrology. 6th
ed. McGraw-Hill, Inc. New York, NY. 510 pp.
Harms, W.R. 1990. Quercus virginiana Mill. live
oak. In: Burns, R.M., and B.H.
Honkala, technical coordinators. Silvics of North
America. Vol. 2 Hardwoods.
Agric. Handb. 654. U.S. Department of
Agriculture, Forest Service.
Washington, D.C. pp. 751-754.
Helm, A.C., N.S. Nicholas, S.M. Zedaker, S.T. Young.
1991. Maritime forests
on Bull Island, Cape Romain, South Carolina.
Bulletin of the Torrey Botanical
Club. 118(2): 170-175.
Johnson, A. F. and M. G. Barbour. 1990. Dunes and
maritime forests. In: Myers,
R.L. and J.J. Ewel, eds. Ecosystems of Florida.
University of Central Florida
Press. Orlando, FL. pp. 430-480
Little, E.L. 1979. Checklist of the United States trees
(native and naturalized).
Agric. Handb. 541. U.S. Department of
Agriculture, Forest Service.
Washington, D.C. 375 pp.
Simpson, B.J. 1988. A field guide to Texas trees. Texas
Monthly Press, Austin,
TX. 372 pp.
Haller, J.M 1992. Quercus virginiana: the
southern live oak. Arbor Age 12(5):30
Oosting, H.J. 1954. Ecological processes and vegetation
of the maritime strand in
the southeastern United States. Botanical Review.
Van Dersal, W.R. 1938. Native woody plants of the
United States, their
erosion-control and wildlife values. U.S.
Department of Agriculture,
Washington, D.C. 362 pp.
Vince, S.W., S.R. Humphrey, R.W. Simons. 1989. The
ecology of hydric
hammocks: a community profile. Biological Rep.
85(7.26). U.S. Department
of the Interior, Fish and Wildlife Service,
Research and Development.
Washington, D.C. 82 pp.
Vines, R.A. 1960. Trees, shrubs and woody vines of the
southwest. University of
Texas Press, Austin, TX. 1104 pp.
Woolfenden, R.P. 1982. Nesting and survival in a
population of Florida scrub jays.
Living Bird. 12:25-49.
Report by: K. Hill, Smithsonian Marine Station
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Page last updated: Oct. 24, 2001