oak

1. 1. Any of numerous monoecious deciduous or evergreen trees or shrubs of the genus Quercus, bearing acorns as fruit.
   2. The durable wood of any of these trees or shrubs.
   3. Something made of this wood.
2. Any of various similar trees or shrubs, such as the poison oak.
3. Any of various brown shades resembling the wood of an oak in color.

[Middle English ok, from Old English āc.]

(click to enlarge)
Black oak (Quercus velutina) (credit: Walter Dawn)

Any of about 450 species of ornamental and timber trees and shrubs that make up the genus Quercus in the beech family, found throughout temperate climates. Oaks are deciduous trees that bear spring catkins (male flowers) and spikes (female flowers) on the same tree. The leaves have lobed, toothed, or smooth margins. The fruit is the acorn. They are hardy and long-lived shade trees. White oaks have smooth leaves and rapidly germinating sweet acorns; red, or black, oaks have bristle-tipped leaves and bitter, hairy acorns. Red- and white-oak lumber is used in construction, flooring, furniture, millwork, barrel making, and the production of crossties, structural timbers, and mine props. The genus includes many ornamentals and natural hybrids.

For more information on oak, visit Britannica.com.

A genus (Quercus) of trees, some of which are shrubby, with about 200 species, mainly in the Northern Hemisphere. About 50 species are native in the United States. All oaks have scaly winter buds, usually clustered at the ends of the twigs, and single at the nodes. The fruit is a nut (acorn). The leaves are simple and usually lobed.

Oaks furnish the most important hardwood lumber in the United States. Principal uses are for charcoal, barrels, building construction, flooring, railroad ties, mine timbers, boxes, crates, vehicle parts, ships, agricultural implements, caskets, woodenware, fence posts, piling, and veneer. Oak is also used for pulp and paper products. See also Fagales.

Description

Oak is the common name for many acorn-producing trees and shrubs that are members of the beech, or Fagaceae, family. Oak trees are classified as members of the genus Quercus, a Latin word said to be derived from a Celtic word meaning "fine tree." Worldwide there are more than 600 different species of oak. They thrive across the Northern Hemisphere in China, Japan, Europe, the British Isles, and in all of the continental United States except for Alaska. More than half of the 600 species are native to North America. Yet only about 60 varieties grow north of Mexico. In the forests of northern areas that have short summer growing seasons and long winters, such as Canada, northern Europe, and Siberia, varieties of oak are very scarce.

The oak family is a diverse group of trees and shrubs, influenced by climatic and environmental changes. Recent studies indicate that global warming contributes to oak dieback by speeding up the reproduction of beetles and fungi that attack oak trees. There are oaks that grow to heights of about 100 ft (30.5 m), while other types never grow larger than a small shrub. In warmer climates, oaks are evergreens, keep their leaves all year long, and are often used as ornamental trees in parks. In colder climates, they usually drop their leaves in autumn.

Many of these deciduous oaks have leaves that turn brilliant gold or scarlet in the autumn. In spring small, yellow green flowers appear. The male flowers hang in clusters called catkins and have profuse amounts of pollen. This oak pollen is carried by the wind to fertilize female flowers that produce acorns. Oak trees grow very slowly. In 80 years, it's estimated that one will grow to no more than 2 ft (0.6 m) in diameter. Oaks do not even produce acorns for their first 20 years, but they live a very long time. Average life expectancy for most oaks is between 200 and 400 years, and there are oak trees over 800 years old that are still alive.

Oaks are divided into two basic categories: white and red. The leaves of most of these are characteristically lobed, and depending upon the variety, can have anywhere from five to 11 lobes. Historically, the oak has been considered sacred by many civilizations. Abraham's Oak, the Oak of Mamre, is thought to be on the spot where the bible states Abraham pitched his tent. Legend states that anyone defacing this tree will lose their firstborn son. Both the ancient Greeks and Romans revered the oak, but its longest association has been with the British Isles. The Druids considered it to have both medicinal and mystical significance. For centuries, an oak sprig was inscribed on English coins. Legend states that King Arthur's round table was made from one gigantic slice of a very ancient oak tree. Oak has been used as a medicine since the ancient Greek and Roman times. The famous Roman doctor Galen first used oak leaves to heal wounds.

The American white oak, Quercus alba, and the English oak, Quercus robur, have bark with similar healing qualities. Oak bark contains saponins, tannins, calcium oxalate, starch, glycosides, oak-red, resin, pectin, levulin, and quercitol.

General Use

Oak wood as timber is prized for its strength, elasticity, and durability. It is ideal for making furniture, barrels, railroad ties, and in the past, ships. Oak acorns are a source of food for wildlife and have been used as fodder for farm animals in the past. A flour made from ground acorns was also a part of the diet of Native Americans. The tannin in oak bark is used in leather preparation. Cork is made from the bark of some species that grow only in Spain and Portugal.

Recent advances in molecular genetics have shown that DNA from samples of oak can be isolated and analyzed. This type of analysis has a variety of potential applications in archaeology and forensic investigations.

Oak used to make wine barrels has been found to increase the antioxidant activity of wines aged in the barrels as well as adding a distinctive aroma to the wine. The increase in antioxidant activity can be measured by a new technique known as electron paramagnetic resonance, or EPR.

Oak bark is used in medicine as a bowel astringent to treat diarrhea and as an anti-inflammatory gargle for soothing sore throats. It can be used topically for such skin inflammations as dermatitis, as an enema for hemorrhoids, or as a douche for vaginal infections and leukorrhea. A study in 1980 showed some evidence that oak bark may prevent kidney stone formation and act as a diuretic. A 1990 Russian study demonstrated that oak bark had antibacterial activity against Staphylococcus. One study in 1994 showed that oak bark could reduce serum cholesterol levels in animals.

Preparations

One teaspoonful of pulverized oak bark powder can be added to 1 cup of water, boiled, and then simmered at a reduced heat for 15 minutes to make an oak bark tea. This tea can be taken internally as an intestinal astringent up to three times per day. Oak bark is also available in both an extract and a tincture. For rinses, compresses, and gargles, 20 g of pulverized bark should be dissolved in 1 qt (1 L) of water, and prepared in the same manner as the tea. Oak bark is also available as snuff, tablets, and capsules.

Precautions

Oak bark should not be used externally over large areas of skin damage or used as a full bath. Oak bark for gargles, enemas, or douches should not be used for more than two weeks before consulting a doctor. A doctor should also be consulted for any episode of diarrhea that lasts longer than three days despite treatment with oak bark.

Side Effects

No side effects have been reported when oak preparations are used at recommended dosage levels. Patients occasionally experience mild stomach upset or constipation if the dosage is exceeded.

Interactions

Oak bark preparations are believed to inhibit or reduce the absorption of such alkaline drugs as antacids. In addition, oak bark has been found to reduce the effectiveness of codeine and atropine.

Resources

Books

Grieve, M., and C. F. Leyel. A Modern Herbal: The Medical, Culinary, Cosmetic and Economic Properties, Cultivation and Folklore of Herbs, Grasses, Fungi, Shrubs and Trees With All of Their Modern Scientific Uses. Barnes and Noble Publishing, 1992.

Hoffman, David, and Linda Quayle. The Complete Illustrated Herbal: A Safe and Practical Guide to Making and Using Herbal Remedies. Barnes and Noble Publishing, 1999.

Periodicals

Deguilloux, M. F., M. H. Pemonge, and R. J. Petit. "Novel Perspectives in Wood Certification and Forensics: Dry Wood as a Source of DNA." Proceedings of the Royal Society of London, Series B, Biological Sciences 269 (May 22, 2002): 1039-1046.

Diaz-Playa, E. M., J. R. Reyero, F. Pardo et al. "Influence of Oak Wood on the Aromatic Composition and Quality of Wines with Different Tannin Contents." Journal of Agriculture and Food Chemistry 50 (April 24, 2002): 2622-2626.

Kamata, N., N. Kamata, K. Esaki, et al. "Potential Impact of Global Warming on Deciduous Oak Dieback Caused by Ambrosia Fungus Raffaelea sp. Carried by Ambrosia Beetle Platypus quercivorus (Coleoptera: Platypodidae) in Japan." Bulletin of Entomological Research 92 (April 2002): 119-126.

Troup, G. J., and C. R. Hunter. "EPR, Free Radicals, Wine, and the Industry: Some Achievements." Annual of the New York Academy of Science (May 2002): 345-347.

Organizations

Herbal Advisor. http//www.AllHerb.com

OnHealthHerbal Index. "Oak Bark." http//www.OnHealth.com

[Article by: Joan Schonbeck; Rebecca J. Frey, PhD]

The oak symbolizes steadfast courage, royalty, and England. There are specific associations with the Royal Navy, and with the Restoration of the monarchy in 1660, celebrated on Royal Oak Day.

Individual oaks can be locally famous. Many are called ‘Gospel Oaks’, because they mark a spot on the parish boundary where Rogation processions used to pause while a Gospel passage was read. One in Sherwood Forest is said to have been a meeting-place for Robin Hood and his men. Another, at Clipstone (Nottinghamshire) is the Parliament Oak, so called because either King John or Edward I convened a Parliament there. Another, in the grounds of Boscobel House (Shropshire) is said to be the one in which Charles II hid after the Battle of Worcester, while all along the route of his escape there are trees (not necessarily oaks) in which, it is claimed, he also hid from pursuers—for example an oak near Melksham Court (Gloucestershire), and a hollow elm in Brighton (Sussex). Wesley several times held open-air services at the tree now called Wesley's Oak near Altrincham (Cheshire).

Cords of window-blinds had a toggle shaped like an acorn, which was said to prevent lightning from entering through the window, since it was believed (mistakenly) that oak trees are never struck by lightning. Such blinds are now rare, so the belief must be dying out. Grated oak bark or acorns were a country remedy for diarrhoea, and an infusion of oak bark was drunk for rheumatism (Hatfield, 1994: 36, 46).

A tough, hard, high-density wood of the temperate climates; rather coarse-textured, ranging in color from light tan to pink or brown; used for both structural and decorative applications, such as framing timbers, flooring, and plywood.

The mighty deciduous hardwood (genus Quercus) has played a prominent role in the Celtic imagination from ancient to modern times. The English word ‘druid’ (from the Latin plural druidae) derives in part from the root dru- [oak]; Celtic words for oak, e.g. Old Irish and Modern Irish dair, Welsh derwen, share the same root. The ancient geographer Strabo (1st cent. AD) reported that the important sacred grove and meeting-place of the Galatian Celts of Asia Minor, Drunemeton, was filled with oaks. In an often-cited passage from Historia Naturalis (1st cent. AD), Pliny the Elder describes a festival on the sixth day of the moon where the druids climbed an oak tree, cut a bough of mistletoe, and sacrificed two white bulls as part of a fertility rite. Elsewhere druids made their wands from only three woods: yew, oak, and apple. In Mediterranean culture the oak was sacred to both Zeus and Jupiter, some aspects of which were no doubt transferred to the worship of Gaulish Jupiter. Britons under Roman occupation worshipped a goddess of the oak tree, Daron, whose name is commemorated in a rivulet in Gwynedd. According to the pseudo-history Lebor Gabála [Book of Invasions], the sacred oak of early Ireland was that of Mugna, probably located at or near Dunmanogoe, south Co. Kildare. Sacred associations of oaks survived Christianization, so that St Brigit's monastic foundation was at Cill Dara [church of (the) oak, i.e. Kildare], and St Colum Cille favoured Doire Calgaich [Calgach's oak grove, i.e. (London-)Derry]; see also DURROW [darú, from dair magh, oak plain]. In Welsh tradition Gwydion and Math use the flower of oak with broom to fashion the beautiful Blodeuwedd. When Lleu Llaw Gyffes is about to be killed by Gronw Pebyr, his wife's lover, he escapes in eagle form onto a magic oak tree. A sacred oak tree protects the Breton city of Ys until the feckless boy Kristof removes it, allowing Ys tobe engulfed. The Arthurian figure Merlin is imprisoned in an oak tree in the Breton forest of Brocéliande by Viviane/Nimiane (the Lady of the Lake). In both British and Irish fairy lore, the oak is one of three magical woods, along with ash and thorn. Old Irish and Modern Irish dair; Scottish Gaelic darach; Manx daragh; Welsh derwen, dâr; Cornish derowen; Breton dervenn.

The preferred wood for making the barrels and casks in which wine is aged. Oak barrels impart flavors and tannins, both of which are desirable for most red wine as well as some white wines. Oak is slightly porous, which creates an environment ideal for aging wines. Redwood and chestnut are distant second choices to oak, and neither do the job as well. Sometimes these woods are used for larger casks because the expense of using oak is a luxury. Despite oak's unique capabilities, more delicate wines do not do well with oak aging of any length, and some wines can easily become over-oaked. In either case, oak flavors and tannins can overpower a wine's varietal character, which results in a poorly balanced wine. Oak is also a matter of personal taste. For instance, some wine lovers prefer big, oaky chardonnays, while others prefer leaner, cleaner styles where the oak character isn't so prominent. Choosing the right barrel requires some knowledge of and experience with various types of oak, as well as the coopers who make the barrels. The favorite wood for wine barrels is white oak (red oak is too porous), with the U.S. Species differing slightly from European. In Europe, the primary sources of oak are France and the former Yugoslavia. The best-known French sources are limousin, a forest in south-central France; central France's forests of Allier, Nevers, and Troncais; and Vosges, a forest in northeastern France. The leading sources of white oak in the United States are Kentucky, Min­nesota, Missouri, Ohio, Tennessee, and Wisconsin. There's a great deal of discussion about how the oak from different locations affects various types of wines. Some believe that Limousin oak, which has a looser grain, imparts more oak flavor, while others say that it delivers less. Most agree that American oak imparts a slightly sweeter character than European oak. However, it's also argued that the cooper's barrel-­making technique has as much to do with the barrel's effect on wine as the wood from which it's made. Barrel making in America (which was primarily for the distilled spirit industry) was much different than that found in Europe. This is now changing, with many European barrel makers opening cooperages in California to handle the expanded demand from California winemakers. Oak barrels lose their ability to impart flavor in 4 to 5 years, and most high-quality wine estates and châteaux replace all or part of their oak barrels with new ones each year so a high level of new oak character is imparted to each new vintage.

The sturdy and majestic oak tree represents stability, steadfastness, truth, tolerance, and wisdom. Psychologically, persons who identify with this symbol are seen to embody these qualities in their character. Commercially, the symbol of the oak tree is frequently used as a logo, implying strength and stability in business practices or civic pursuits.

"Quercus" redirects here. For other uses, see Quercus (disambiguation).

This article is about oaks (Quercus). For other uses of "Oak" or "Oak tree", see Oak (disambiguation).

Oak
Foliage and acorns of Quercus robur
Scientific classification
Kingdom:	Plantae
Phylum:	Magnoliophyta
Class:	Magnoliopsida
Order:	Fagales
Family:	Fagaceae
Genus:	Quercus L.
Species
See List of Quercus species

An oak is a tree or shrub in the genus Quercus (pronounced /ˈkwɜrkəs/;^[1] Latin "oak tree"), of which about 400 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus. The genus is native to the northern hemisphere, and includes deciduous and evergreen species extending from cold latitudes to tropical Asia and the Americas.

Oaks have spirally arranged leaves, with a lobed margin in many species; some have serrated leaves or entire leaves with a smooth margin. The flowers are catkins, produced in spring. The fruit is a nut called an acorn, borne in a cup-like structure known as a cupule; each acorn contains one seed (rarely two or three) and takes 6–18 months to mature, depending on species. The live oaks are distinguished for being evergreen, but are not actually a distinct group and instead are dispersed across the genus.

Contents 1 Classification 1.1 Subgenus Quercus 1.2 Subgenus Cyclobalanopsis 2 Hybridisation 3 Uses 4 Diseases and pests 5 Toxicity 6 Cultural significance 6.1 Political or symbolic 6.2 Mythological 6.3 Historical 7 Historical note on Linnaean species 8 Gallery 9 See also 10 Notes 11 References 12 External links

Classification

Oak trees are flowering plants. The genus is divided into two subgenera and a number of sections:

Subgenus Quercus

See also: List of Quercus species

The Subgenus Quercus is divided into the following sections:

• Sect. Quercus (synonyms Lepidobalanus and Leucobalanus), the white oaks of Europe, Asia and North America. Styles are short; acorns mature in 6 months and taste sweet or slightly bitter; the inside of acorn shell is hairless. The leaves mostly lack a bristle on their lobe tips, which are usually rounded.
• Sect. Mesobalanus, Hungarian oak and its relatives of Europe and Asia. Styles long; acorns mature in about 6 months and taste bitter; the inside of acorn shell is hairless. The section Mesobalanus is closely related to section Quercus and sometimes included in it.
• Sect. Cerris, the Turkey oak and its relatives of Europe and Asia. Styles long; acorns mature in 18 months and taste very bitter. The inside of the acorn shell is hairless. Its leaves typically have sharp lobe tips, with bristles at the lobe tip.
• Sect. Protobalanus, the Canyon live oak and its relatives, in southwest United States and northwest Mexico. Styles short, acorns mature in 18 months and taste very bitter. The inside of the acorn shell appears woolly. Leaves typically have sharp lobe tips, with bristles at the lobe tip.
• Sect. Lobatae (synonym Erythrobalanus), the red oaks of North America, Central America and northern South America. Styles long, acorns mature in 18 months and taste very bitter. The inside of the acorn shell appears woolly. The actual nut is encased in a thin, clinging, papery skin. Leaves typically have sharp lobe tips, with spiny bristles at the lobe.

Subgenus Cyclobalanopsis

• The ring-cupped oaks of eastern and southeastern Asia. Evergreen trees growing 10–40 m tall. They are distinct from subgenus Quercus in that they have acorns with distinctive cups bearing concrescent rings of scales; they commonly also have densely clustered acorns, though this does not apply to all of the species. The Flora of China treats Cyclobalanopsis as a distinct genus, but most taxonomists consider it a subgenus of Quercus. It contains about 150 species.

A hybrid white oak, possibly Quercus stellata × Q. muhlenbergii

Hybridisation

Interspecific hybridisation is quite common among oaks, but usually only between species within the same section and most common in the white oak group (subgenus Quercus, section Quercus; see List of Quercus species). Inter-section hybrids, except between species of sections Quercus and Mesobalanus, are unknown. Recent systematic studies appear to confirm a high tendency of Quercus species to hybridize because of a combination of factors. White oaks are unable to discriminate against pollination by other species in the same section because they are wind pollinated and they have weak internal barriers to hybridisation, hybridization produces functional seeds and fertile hybrid offspring.^[2] Ecological stresses, especially near habitat margins, can also cause a breakdown of mate recognition as well as a reduction of male function (pollen quantity and quality) in one parent species.^[2][3]

Frequent hybridisation among oaks has consequences for oak populations around the world; most notably, hybridization has produced large populations of hybrids with copious amounts of introgression, and the evolution of new species.^[4] Frequent hybridisation and high levels of introgression have caused different species in the same populations to share up to 50% of their genetic information.^[5] The high rates of hybridisation and introgression, produces genetic data that often does not differentiate between two clearly morphologically distinct species, but instead differentiates populations.^[6] Numerous hypotheses have been proposed to explain how oak species are able to remain morphologically and ecologically distinct with such high levels of gene flow, but the problem is still largely a mystery to botanists.

The Fagaceae, or oak family, is a very slowly evolving clade compared to other angiosperms,^[7][8] and the hybridisation patterns in Quercus pose a great challenge to the concept of a species.^{[citation needed]} A species is often defined as a group of “actually or potentially interbreeding populations which are reproductively isolated from other such groups.”^[9] By this definition, many species of Quercus would be lumped together according to their geographic and ecological habitat, despite clear distinctions in morphology and, to a large extent, genetic data. Thus, although it may be difficult to place a definition on a species within a genus like Quercus, it is trivial and uninformative to apply the biological species concept to all forms of life.^{[citation needed]}

Uses

Oak wood has a density of about 0.75 g/cm³, great strength and hardness, and is very resistant to insect and fungal attack because of its high tannin content. It also has very attractive grain markings, particularly when quartersawn. Wide, quarter-sawn boards of oak have been prized since the Middle Ages for use in interior paneling of prestigious buildings such as the debating chamber of the British House of Commons in London, England, and in the construction of fine furniture. Oak wood, from Quercus robur and Quercus petraea, was used in Europe for the construction of ships, especially naval men of war, until the 19th century, and was the principal timber used in the construction of European timber-framed buildings. Today oak wood is still commonly used for furniture making and flooring, timber frame buildings, and for veneer production. Barrels in which red wines, sherry, brandy and spirits such as Scotch whisky and Bourbon whiskey are aged are made from European and American oak. The use of oak in wine can add many different dimensions to wine based on the type and style of the oak. Oak barrels, which may be charred before use, contribute to the colour, taste, and aroma, of the contents, imparting a desirable oaky vanillin flavour to these drinks. The great dilemma for wine producers is to choose between French and American oakwoods. French oaks (Quercus robur, Q. petraea) give the wine greater refinement and are chosen for best wines since they increase the price compared to those aged in American oak wood.^[10] American oak contributes greater texture and resistance to ageing, but produces more violent wine bouquets.^[10] Oak wood chips are used for smoking fish, meat, cheeses^[11][12] and other foods.

Sherry maturing in oak barrels

A cross section of the trunk of a cork oak, Quercus suber

The bark of Quercus suber, or Cork oak, is used to produce wine stoppers (corks). This species grows in the Mediterranean Sea region, with Portugal, Spain, Algeria and Morocco producing most of the world's supply. Of the North American oaks, the Northern red oak Quercus rubra is the most prized of the red oak group for lumber, all of which is marketed as red oak regardless of the species of origin. It is not good for outdoor use due to the open capillaries. One can blow air through an end grain piece 10 inches long to make bubbles come out in a glass of water. These opening give fungus easy access when the finish deteriorates. The standard for the lumber of the white oak group, all of which is marketed as white oak, is the White Oak Quercus alba. White Oak is often used to make wine barrels. The wood of the deciduous Pedunculate Oak Quercus robur and Sessile Oak Quercus petraea account for most of the European oak production, but evergreen species, such as Holm oak Quercus ilex, and Cork oak Quercus suber also produce valuable timber.

The bark of the White Oak is dried and used in medical preparations. Oak bark is also rich in tannin, and is used by tanners for tanning leather. Acorns are used for making flour or roasted for acorn coffee. Oak galls were used for centuries as the main ingredient in manuscript ink, harvested at a specific time of year.

Japanese oak is used in the making of professional drums from manufacturer Yamaha Drums. The rough, hard surface of oak gives the drum a brighter and louder tone compared to traditional drum materials such as maple and birch.^{[citation needed]}

Diseases and pests

See also: List of Lepidoptera that feed on oaks

Oak Mildew on Pedunculate Oak.

Sudden Oak Death (Phytophthora ramorum) is a water mould that can kill oaks within just a few weeks. Oak Wilt, caused by the fungus Ceratocystis fagacearum (a fungus closely related to Dutch Elm Disease), is also a lethal disease of some oaks, particularly the red oaks (the white oaks can be infected but generally live longer). Other dangers include wood-boring beetles, as well as root rot in older trees which may not be apparent on the outside, often only being discovered when the trees come down in a strong gale. Oak apples are galls on oaks made by the gall wasp. The female kermes scale causes galls to grow on kermes oak. Oaks are used as food plants by the larvae of Lepidoptera (butterfly and moth) species such as the Gypsy Moth, Lymantria dispar, which can defoliate oak and other broadleaved tree species in North America.^[13]

A considerable number of galls are found on oak leaves, buds, flowers, roots, ect. Examples are Oak artichoke gall, Oak Marble gall, Oak apple gall, Knopper gall, and Spangle gall.

Toxicity

The leaves and acorns of the oak tree are poisonous to horses in large amounts, due to the toxin tannic acid, and cause kidney damage and gastroenteritis. Additionally, once horses have a taste for the leaves and acorns, they may seek them out. Therefore, horse owners are encouraged to fence out oak trees from their pasture, especially if forage is scarce. Symptoms of poisoning include lack of appetite, depression, constipation, diarrhea (which may contain blood), blood in urine, and colic.

Cultural significance

Oak branches on the coat of arms of Estonia

Political or symbolic

The oak is a common symbol of strength and endurance and has been chosen as the national tree of England, Estonia, France, Germany, Moldova, Latvia, Lithuania, Poland, the United States, Basque Country, Wales, Bulgaria and Serbia.^{[citation needed]} Iowa has designated the oak as its official state tree in 1961, and the White Oak is the state tree of Connecticut, Illinois and Maryland. The Northern Red Oak is the provincial tree of Prince Edward Island, as well as the state tree of New Jersey. The Live Oak is the State Tree of Georgia.

The oak is the emblem of County Londonderry in Northern Ireland, as a vast amount of the county was covered in forests of the tree until relatively recently. The name of the county comes from the city of Derry, which originally in Irish was known as Doire meaning oak.

Oak leaves are traditionally an important part of German Army regalia. They also symbolize rank in the United States Armed Forces. A gold oak leaf indicates an O-4 (Major or Lt. Commander), whereas a silver oak leaf indicates an O-5 (Lt. Colonel or Commander). Arrangements of oak leaves, acorns and sprigs indicate different branches of the United States Navy Staff corps officers. Oak leaves are embroidered onto the covers worn by field grade officers and flag officers in the United States armed services.

The oak tree is used as a symbol by a number of political parties. It is the symbol of the Conservative Party in the United Kingdom^[14], and formerly of the Progressive Democrats in Ireland^[15]. In the cultural arena, the oakleaf is the symbol of the National Trust (UK) and The Royal Oak Foundation.

Mythological

In Celtic mythology, it is the tree of doors, believed to be a gateway between worlds, or a place where portals could be erected.^{[citation needed]}

In Norse mythology, the oak was sacred to the thunder god, Thor. Some scholars speculate that this is because the oak, as the largest tree in northern Europe, was the one most often struck by lightning. Thor's Oak was a sacred tree of the Germanic Chatti tribe. Its destruction marked the Christianisation of the heathen tribes by the Franks^{[citation needed]}.

In Classical mythology, the oak was a symbol of Zeus and his sacred tree. An example is the oracle of Dodona, which in prehistory consisted solely of a holy oak.^{[citation needed]}

The Oak tree is traditionally sacred to Serbs and is widely used throughout Serbia on national and regional symbols both old and new.^{[citation needed]}

In the Bible, the oak tree at Shechem is the site where Jacob buries the foreign gods of his people (Gen. 35:4) . In addition, Joshua erects a stone under an oak tree as the first covenant of the Lord (Josh. 24.25-7). In Isaiah 61, the prophet refers to the Israelites as "Oaks of Righteousness".

Historical

Several individual oak trees, such as the Royal Oak in Britain and the Charter Oak in the United States, are of great historical or cultural importance; for a list of important oaks, see Individual oak trees.

"The Proscribed Royalist, 1651", a famous painting by John Everett Millais, depicted a Royalist fleeing from Cromwell's forces and hidden in an oak. Millais painted the picture in Hayes, Kent, from a local oak tree that became known as the Millais Oak.^[16]

The city of Raleigh, N.C. is known as "The City of a Thousand Oaks."

Historical note on Linnaean species

Linnaeus described only five species of oak from eastern North America, based on general leaf form. These were White oak, Quercus alba; Chestnut oak, Q. Montana; Red oak, Q. rubra; Willow oak Q. phellos; and Water oak, Q. nigra. Because he was dealing with confusing leaf forms, the Q. prinus and Q. rubra specimens actually included mixed foliage of more than one species. For that reason, some taxonomists in the past proposed different names for these two species (Q. montana and Q. borealis, respectively), but the original Linnaean names have now been lectotypified by removing some of the specimens in Linnaeus' herbarium.

Gallery

A Pedunculate oak in Denmark	An oak tree at night	Bark of Quercus robur	Southern live oak with spanish moss
Quercus mongolica Mongolian Oak in Minnesota Landscape Arboretum	Old oak in Liernu, Belgium.	The Duke Prosper Oak in Enghien (Belgium).	Quercus petraea Sessile Oak in Sivry-Rance (Belgium).
Form of Kindred Spirit Hybrid Oak.	Angel Oak on Johns Island, South Carolina.	The Major Oak is an 800–1000 year old oak in Sherwood Forest, famed as the alleged principal hideout of Robin Hood.	The Mustard Powder lichen or Gold Dust lichen is common on old oak bark.

See also

• List of plants poisonous to equines

Notes

1. ^ Sunset Western Garden Book, 1995:606–607
2. ^ ^{a b} Williams, Joseph H., William J. Boecklen, and Daniel J. Howard. 2001 Reproductive processes in two oak (Quercus) contact zones with different levels of hybridisation. Heredity 87: 680–690.
3. ^ Arnold, M. L. 1997. Natural Hybridization and Evolution. Oxford University Press, New York.
4. ^ Conte, L., Cotti, C., and Cristofolini, G. 2007 Molecular evidence for hybrid origin of Quercus crenata Lam. (Fagaceae) from Q-cerris L. and Q-suber L. Plant Biosystems 141 (2): 181–193.
5. ^ Gomory, D. and Schmidtova, J. 2007 Extent of nuclear genome sharing among white oak species (Quercus L. subgen. Lepidobalanus (Endl.) Oerst.) in Slovakia estimated by allozymes. Plant Systematics and Evolution 266 (3-4): 253–264.
6. ^ Kelleher, CT., TR Hodkinson, GC Doublas, and DL Kelly. 2005 Species distinction in Irish populations of Quercus petraea and Q. robur: Morphological versus molecular analyses. Annals of Botany 96 (7): 1237–1246.
7. ^ Frascaria, N., L. Maggia, M. Michaud, and J. Bousquet. 1993 The RBCL Gene Sequence from Chestnut Indicates a Slow Rate of Evolution in the Fagaceae. Genome 36 (4): 668–671.
8. ^ Manos, PS., AM Stanford. 2001b The historical biogeography of Fagaceae: Tracking the tertiary history of temperate and subtropical forests of the Northern Hemisphere. International Journal of Plant Sciences 162: S77-S93 Suppl. 6.
9. ^ Raven, Peter H., George B. Johnson, Jonathan B. Losos, Susan R. Singer. Biology: Seventh Edition. McGraw Hill, New York, NY 2005.
10. ^ ^{a b} (Spanish) La crianza del vino La Razón 23 de Agosto de 2007^{[dead link]}
11. ^ 200g Oak Smoked Wensleydale – Williams Deli – tearoom richmond north
12. ^ http://www.swaledalecheese.co.uk/cheese.htm
13. ^ http://www.treehelp.com/trees/oak/oak-insects-gypsymoth.asp
14. ^ http://www.conservatives.com
15. ^ http://www.progressivedemocrats.ie/about_us/coalition_government_1989_to_1992/
16. ^ Millais, J.G., Life and Letters of Sir John Everett Millais, vol. 1, p.166; See also Arborecology, containing a photograph of the Millais oak

References

• Byfield, Liz (1990) An oak tree, Collins book bus, London : Collins Educational, ISBN 0-00-313526-8
• Logan, William B. (2005) Oak : the frame of civilization, New York ; London : W.W. Norton, ISBN 0-393-04773-3
• Paterson, R.T. (1993) Use of trees by livestock, 5: Quercus, Chatham : Natural Resources Institute, ISBN 0-85954-365-X
• Royston, Angela (2000) Life cycle of an oak tree, Heinemann first library, Oxford : Heinemann Library, ISBN 0-431-08391-6
• Savage, Stephen (1994) Oak tree, Observing nature series, Hove : Wayland, ISBN 0-7502-1196-2
• Tansley, Arthur G., Sir (1952) Oaks and oak woods, Field study books, London : Methuen, 50 p.

External links

Wikimedia Commons has media related to: Quercus

Wikispecies has information related to: Quercus

• Flora of North America: Quercus
• Flora of China: Quercus
• Flora of China – Cyclobalanopsis
• Flora Europaea: Quercus
• Oak Trees of the Lowcountry (South Carolina) – Beaufort County Library
• (English) Oaks from Bialowieza Forest
• (English) Common Oaks of Florida
• Oak leaves and their use in aquariums
• Oaks of the world

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - eg

Nederlands (Dutch)
eik, eiken, eikenhout, eikenboom, zomereik

Français (French)
n. - chêne

Deutsch (German)
n. - Eiche, Eichenholz

Ελληνική (Greek)
n. - (φυτολ.) βαλανιδιά, δρυς, ξύλο βαλανιδιάς

Italiano (Italian)
quercia, legno di quercia

Português (Portuguese)
n. - carvalho (m)

Русский (Russian)
дуб

Español (Spanish)
n. - roble, madera de roble

Svenska (Swedish)
n. - ek, ekträ

中文（简体）(Chinese (Simplified))
橡树, 橡木

中文（繁體）(Chinese (Traditional))
n. - 橡樹, 橡木

한국어 (Korean)
n. - 떡갈나무, 견고한 바닥 문짝 , 오크 장식

日本語 (Japanese)
n. - オーク, オーク材

العربيه (Arabic)
‏(الاسم) بلوط, سنديان‏

עברית (Hebrew)
n. - ‮אלון, עשוי מעץ אלון, דלת כבדה (בבריטניה)‬

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