Biology:Live oak

From HandWiki
Short description: Group of evergreen trees in the oak genus Quercus
Sand live oak (Quercus geminata)
Texas live oak
Texas live oak (Quercus fusiformis)

Live oak or evergreen oak is any of a number of oaks in several different sections of the genus Quercus that share the characteristic of evergreen foliage.[1] These oaks are generally not more closely related to each other than they are to other oaks.[1]

The name live oak comes from the fact that evergreen oaks remain green and "live" throughout winter, when other oaks are dormant and leafless. The name is used mainly in North America, where evergreen oaks are widespread in warmer areas along the Atlantic coast from southeast Virginia to Florida, west along the Gulf Coast to Louisiana and Mexico, and across the southwest to California .

Evergreen oak species are also common in parts of southern Europe and south Asia, and are included in this list for the sake of completeness. These species, although not having "live" in their common names in their countries of origin, are colloquially called live oaks when cultivated in North America.

When the term live oak is used in a specific rather than general sense, it most commonly refers to the group of species under Quercus sect. Virentes, which includes the southern live oak (Quercus virginiana), the first species so named, and an icon of the Old South.[2]

According to the Live Oak Society the oldest southern live oak is believed to be the Seven Sisters Oak located in Mandeville, Louisiana with an estimated age of 500–1,000 years.[3]

The southern live oak is the official state tree of Georgia.

The Seal of Texas includes a live oak branch.

A small grove of live oaks on a prairie is known as a mott.[4]

Wood and lumber

Live oak was widely used in early American butt shipbuilding. Because of the trees' short height and low-hanging branches, lumber from live oaks was used in curved parts of the frame, such as knee braces (single-piece, L-shaped braces that spring inward from the side and support the deck), in which the grain runs perpendicular to structural stress, making for exceptional strength. Live oaks were not generally used for planking because the curved and often convoluted shape of the tree did not lend itself to being milled to planking of any length. Red oak and white oak were generally used for planking on vessels, because those trees grow straight and tall, with straight trunks long enough for planks.

Loggers had cut down most of the live oak trees in southern Europe by the latter half of the 19th century. Live oak timber from the United States was similarly sought and exported until metal-hulled commercial vessels became the norm in the early part of the 20th century. Live oak lumber is rarely used for furniture, because it warps and twists while drying.

The wood of live oaks continues to be used occasionally in shipbuilding—and in tool handles for its strength, energy absorption, and density, although modern composites are often substituted with good effect. Dry Southern live oak lumber has a specific gravity of 0.88, among the highest of North American hardwoods.

List of evergreen species in genus Quercus


References

  1. 1.0 1.1 Miller, George Oxford (7 April 2006). Landscaping with Native Plants of Texas. Voyageur Press. p. 82. ISBN 9780760325391. https://books.google.com/books?id=3PbQaKSDJfUC&pg=PA82. Retrieved 20 October 2010. 
  2. Bender, Steve, ed (January 2004). "Quercus virginiana". The Southern Living Garden Book (2nd ed.). Birmingham, Alabama: Oxmoor House. ISBN 0-376-03910-8. 
  3. Guion, William (Summer 2018). "Before America Was America" (in en-US). https://www.americanforests.org/magazine/article/before-america-was-america/. 
  4. Wheat, Pam; Whorton, Brenda (November 1990). Clues from the Past: A Resource Book on Archeology. Hendrick-Long Pub. Co.. p. 18. ISBN 9780937460658. https://books.google.com/books?id=3ia0x35aOpEC. Retrieved 20 October 2010. 

External links