Southern live oak is an evergreen or nearly evergreen oak tree, Quercus virginiana, native to the southeastern United States. A large number of other common names are used for this tree, including Virginia live oak, Bay live oak, Scrub live oak, Plateau oak, Plateau live oak, Escarpment live oak, and (in Spanish) Encino. It is also often just called 'Live oak' within its native area, but the full name 'Southern live oak' (Flora of North America) helps to distinguish it from other live oaks, a general term for any species of oak that is evergreen.

This profusion of common names partly reflects an ongoing controversy about the classification of various live oaks, in particular its near relatives among the white oaks (Quercus subgenus Quercus, section Quercus). Some authors recognize as distinct species forms that others consider to be varieties of Quercus virginiana. Notably, the following two taxa, treated as species in the Flora of North America, are treated as varieties of Southern live oak by the United States Forest Service:

• Texas live oak, Quercus fusiformis (a.k.a. Q. virginiana var. fusiformis)
• Sand live oak , Quercus geminata (a.k.a. Q. virginiana var. geminata)

Matters are further complicated by the fact that Southern live oak hybridizes with both the above two species, and also with Dwarf live oak (Q. minima), Swamp white oak (Q. bicolor), Durand oak (Q. durandi), Overcup oak (Q. lyrata), Bur oak (Q. macrocarpa), and Post oak (Q. stellata).

Typical Southern live oak is found from southeast Virginia to Florida, including the Florida Keys, and west to southeast Texas. Texas live oak occurs primarily in Texas, on the Edwards Plateau and the Rio Grande Plain, but can be found as far west as Terrell County, Texas, in southwestern Oklahoma and northeastern Mexico. Sand live oak occurs from North Carolina to Florida in the east and Mississippi in the west.

Southern live oak is long-lived. Depending on the growing conditions, they vary from the shrubby to the large large and spreading: typical open-grown trees reach 15 metres (50 feet) in height, but may span nearly 50 metres. Their lower limbs often sweep down towards the ground before curving up again. They can grow at severe angles, and Native Americans used to bend saplings over so that they would grow at extreme angles, to serve as trail markers. They drop their leaves, and grow new ones, within a few weeks in spring. The bark is furrowed longitudinally, and the acorns are small, but long and tapered. Trees frequently have rounded clumps of ball moss or thick drapings of Spanish moss, and mistletoe is often found on them.

Southern live oak can grow in moist to dry sites. They can withstand occasional floods and hurricanes, and are resistant to salt spray and moderate soil salinity. They tend to survive fire, because often a fire will not reach their crowns. Even if a tree is burned, its root crowns and roots usually survive the fire and sprout vigorously. Furthermore live oak forests discourage entry of fire from adjacent communities because they provide dense cover that discourages the growth of a flammable understory. Although they grow best in well-drained sandy soils and loams, they will also grow in clay.

Among the animals for which live oak acorns are an important food source are the Bobwhite Quail, the threatened Florida Scrub Jay, the Wood Duck, Yellow-bellied Sapsucker, Wild Turkey, Black Bear, various species of squirrel, and the White-tailed deer. Native Americans extracted an oil from the acorns. The tree crown is very dense, making it valuable for shade, and the species provides nest sites for many other species.

In the days of wooden ships, live oaks were the preferred source of the framework timbers of the ship, using the natural branch angles for their strength. Trees in excess of 500 years were once common, and one, the Angel Oak on Johns Island, South Carolina is estimated at 1400 years of age. It is threatened by nearby development.

A few cities have managed to preserve their trees, and live oaks, often draped with Spanish moss, are part of the charm of southern cities like Charleston, South Carolina, Georgetown, South Carolina, and Savannah, Georgia.

See also: Treaty Oak

External links

• USDA Fire Ecology Information Service entry on Quercus virginia (source of most of the information above)
• Flora of North America - Quercus
• Myke's Photos of the Angel Oak