Oak 39696 225000822 2008-07-11T11:52:15Z 193.145.220.99 /* External links */ :''This article is about oaks (Quercus). For other uses of "Oak" or "Oak tree", see [[Oak (disambiguation)]]'' {{Taxobox | name = Oaks | image = Quercus robur.jpg | image_width = 240px | image_caption = Foliage and acorns of ''[[Pedunculate oak|Quercus robur]]'' | regnum = [[Plant]]ae | phylum = [[flowering plant|Magnoliophyta]] | classis = [[dicotyledon|Magnoliopsida]] | ordo = [[Fagales]] | familia = [[Fagaceae]] | genus = '''''Quercus''''' | genus_authority = [[Carolus Linnaeus|L.]] | subdivision_ranks = [[Species]] | subdivision = See [[List of Quercus species|List of ''Quercus'' species]] }} The term '''oak''' can be used as part of the common name of any of several hundred species of [[tree]]s and [[shrub]]s in the [[genus]] ''Quercus'' (from [[Latin]] "oak tree"), which are listed in the [[List of Quercus species]], and some 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 [[leaf|leaves]], with a lobed margin in many species; some have serrated leaves or entire leaves with a smooth margin. The [[flower]]s are [[catkin]]s, produced in spring. The [[fruit]] is a [[nut (fruit)|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 oak|"live oaks"]] (oaks with [[evergreen]] leaves) are not a distinct group, instead with their members scattered among the sections below. ==Classification== Oak trees are ''flowering plants''. The genus is divided into two [[subgenera]] and a number of [[section (botany)|sections]]: ===Subgenus ''Quercus:''=== *Sect. ''Quercus'' (synonyms ''Lepidobalanus'' and ''Leucobalanus''), the white [[List of Quercus species#Section Quercus|oaks]] of [[Europe]], Asia and [[North America]]. Styles short; acorns mature in 6 months, sweet or slightly bitter, inside of acorn shell hairless. Leaves mostly lack a bristle on lobe tips, which are usually rounded. *Sect. ''Mesobalanus'', the [[List of Quercus species#Section Mesobalanus|Hungarian oak and its relatives]] of Europe and Asia. Styles long; acorns mature in 6 months, bitter, inside of hairless acorn shell (closely related to sect. ''Quercus'' and sometimes included in it). *Sect. ''Cerris'', the [[List of Quercus species#Section Cerris|Turkey oak and its relatives]] of Europe and Asia. Styles long; acorns mature in 18 months, very bitter, inside of acorn shell hairless. Leaves typically have sharp lobe tips, with bristles at the lobe tip. *Sect. ''Protobalanus'', the [[List of Quercus species#Section Protobalanus|Canyon live oak and its relatives]], in southwest [[United States]] and northwest [[Mexico]]. Styles short, acorns mature in 18 months, very bitter, inside of acorn shell woolly. Leaves typically have sharp lobe tips, with bristles at the lobe tip. *Sect. ''Lobatae'' (synonym ''Erythrobalanus''), the [[List of Quercus species#Section Lobatae|red oaks]] of North America, [[Central America]] and northern [[South America]]. Styles long, acorns mature in 18 months, very bitter, inside of acorn shell woolly. Leaves typically have sharp lobe tips, with spiny bristles at the lobe. ===Subgenus ''Cyclobalanopsis:''=== *The [[List of Quercus species#Subgenus Cyclobalanopsis|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 [http://flora.huh.harvard.edu:8080/flora/browse.do?flora_id=2&taxon_id=108828 ''Flora of China''] treats ''Cyclobalanopsis'' as a distinct [[genus]], but most taxonomists consider it a [[subgenus]] of ''Quercus''. It contains about 150 species. [[List of Quercus species|'''List of ''Quercus'' species''']] [[Image:Quercus stellata.jpg|thumb|A hybrid white oak, possibly ''[[Post oak|Quercus stellata]]'' × ''[[Chinkapin oak|Q. muhlenbergii]]'']] ==Hybridization== [[Hybrid (biology)|Interspecific hybridization]] is quite common among oaks, but usually only between species within the same section and especially in the white oak group (subgenus ''Quercus'', section ''Quercus''; see [[List of Quercus species|'''List of ''Quercus'' species''']]); no verified inter-section hybrids are known, except between species of sections ''Quercus'' and ''Mesobalanus'', where several occur. Hybridization is considered fairly common, if not widespread, in the plant world (certainly much more so than in animal taxa)<ref>Arnold, M. L. 1997. ''Natural Hybridization and Evolution''. Oxford University Press, New York.</ref>. Yet not all plant groups exhibit hybridization. Botanists have often described white oaks as having weak internal barriers to hybridization, that is to say, because they are [[anemophily|wind pollinated]], oaks often do not discriminate against being pollinated by another species in the same section (''Quercus''), thus resulting in fertile hybrid offspring<ref>Williams, Joseph H., William J. Boecklen, and Daniel J. Howard. 2001 Reproductive processes in two oak (''Quercus'') contact zones with different levels of hybridization. ''Heredity'' 87: 680-690.</ref>. 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<ref>Arnold, M. L. 1997. ''Natural Hybridization and Evolution''. Oxford University Press, New York.</ref><ref>Williams, Joseph H., William J. Boecklen, and Daniel J. Howard. 2001 Reproductive processes in two oak (''Quercus'') contact zones with different levels of hybridization. ''Heredity'' 87: 680-690.</ref>. Recent systematic studies appear to confirm the high tendency of ''Quercus'' species to hybridize as a result of a combination of the aforementioned factors. Frequent hybridization has brought about a number of consequences to oak populations around the world. Most notably, hybridization has led to the creation of large populations of hybrids, copious amounts of [[introgression]], and even the [[evolution (biology)|evolution]] of new species<ref>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.</ref>. Frequent hybridization and high levels of introgression have caused different species in the same populations to share up to 50% of their genetic information<ref>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.</ref>. As a result of such high rates of hybridization and introgression, genetic data often does not differentiate between two clearly morphologically distinct species, but rather by different populations<ref>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.</ref>. In spite of numerous hypotheses, the way in which oak species are able to remain morphologically and ecologically distinct with such high levels of gene flow remains largely a mystery to botanists. The consequences of frequent hybridization can also be seen on a higher level. The [[Fagaceae]], the oak family, is known to be a very slowly evolving [[clade]] compared other [[angiosperm]]s<ref>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.</ref><ref>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.</ref>. More than anything, however, hybridization patterns in ''Quercus'' pose a great challenge to the [[biological species concept|concept of a species]]. A species is often defined as a group of “actually or potentially interbreeding populations which are reproductively isolated from other such groups”<ref>Raven, Peter H., George B. Johnson, Jonathan B. Losos, Susan R. Singer. Biology: Seventh Edition. McGraw Hill, New York, NY 2005.</ref>. 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. ==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 quarter-sawn. 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 until the 19th century, and was the principal timber used in the construction of European [[timber framing|timber-framed]] buildings. Today oak[[wood]] is still commonly used for [[furniture]] making and flooring, timber frame buildings, and for veneer production. [[Barrel (storage)|Barrel]]s in which red [[wine]]s, [[sherry]], [[brandy]] and spirits such as [[Scotch whisky]] and [[Bourbon whiskey]] are [[Aging barrel|aged]] are made from European and American oak. The use of [[oak (wine)|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 color, 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. <ref name="larazon">{{es}} [http://www.larazon.es/noticias/noti_viv33894.htm ''La crianza del vino''] ''La Razón'' 23 de Agosto de 2007</ref> American oak contributes greater texture and resistance to ageing, but produces more violent wine bouquets.<ref name="larazon" /> Oak wood chips are used for [[smoking (cooking)|smoking]] fish, meat, [[cheese]]s<ref>[http://www.williamsdeli.co.uk/product_info.php?cPath=66&products_id=256&osCsid=6f34dc1a878e28ab056ea5482a70e355 200g Oak Smoked Wensleydale - Williams Deli - tearoom richmond north<!-- Bot generated title -->]</ref> <ref>http://www.swaledalecheese.co.uk/cheese.htm</ref> and other foods. [[Image:Sherry cellar, Solera system, 2003.jpg|thumb|[[Sherry]] maturing in oak barrels]] [[Image:Cork oak trunk section.jpg|thumb|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]] [[stopper (plug)|stopper]]s (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. The standard for the lumber of the white oak group, all of which is marketed as white oak, is the [[Quercus alba|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 [[live oak|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]].{{Fact|date=July 2007}} The Irish [[Shillelagh (club)|Shillelagh]] is made with oak or blackthorn. ==Diseases and pests== [[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 [[beetle]]s, 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 apple]]s are [[gall]]s on oaks made by the [[gall wasp]]. The female [[kermes (genus)|kermes]] [[scale insect|scale]] causes galls to grow on [[kermes oak]]. Oaks are used as food plants by the [[larva]]e of [[Lepidoptera]] ([[butterfly]] and [[moth]]) species. *''See also [[list of Lepidoptera that feed on oaks]]'' Also another pest is the [[Gypsy moth]]. The [[Gypsy Moth]] is dominant in North America and there are many concerns of the loss of economically critical and ecologically dominant Oak species. ==Toxicity== The leaves and acorns of the Oak tree are poisonous to horses in large amounts, due to the toxin [[tannic acid]], and causes 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 [[equine colic|colic]]. ==Cultural significance== [[Image:Coat of arms of Estonia.svg|right|thumb|Oak branches on the [[coat of arms of Estonia]]]] ===Political or symbolic=== The oak is a common [[symbol]] of [[Virtue|strength]] and [[endurance]] and has been chosen as the [[national tree]] of [[England]], [[Estonia]], [[France]], [[Germany]], [[Lithuania]], [[Poland]], the [[United States]], [[Basque Country (autonomous community)|Basque Country]], [[Wales]] and [[Serbia]]. [[Iowa]] has designated the oak as its official [[list of U.S. state trees|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 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 language|Irish]] was known as ''Doire'' meaning ''oak''. [[Switzerland]]'s 10 Rappen, and 1/2, 1, 2, and 5 Franc coins, and [[Germany]]'s 1, 2, 5, 10, and 50 Pfenning, 1 Mark, and 1, 2, and 5 Euro Cent coins have Oak leaves on them. Oak leaves symbolize rank in the [[United States Armed Forces]]. A gold oak leaf indicates an O-4 ([[Major]] or [[LCDR|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]] [[List of United States Navy staff corps|Staff corps]] officers. Oak leaves were added to the Nazi honor, the [[Knight's Cross of the Iron Cross#Knight.27s Cross with Oak Leaves .28mit Eichenlaub.29|Iron Cross]] for added status. The oak tree is one of the symbols of the [[Alpha Phi Omega]] national service fraternity. ===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. 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]]{{Fact|date=April 2007}}. 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. The Oak tree is traditionally sacred to [[Serbs]] and is widely used throughout [[Serbia]] on national and regional symbols both old and new. ===Biblical=== 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). See other [http://www.biblegateway.com/quicksearch/?quicksearch=oak&x=0&y=0 examples] from the Bible. ===Historical=== Several individual oak trees, such as the [[Royal Oak (tree)|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 [[:Category:Individual oak trees|Individual oak trees]]. ===Poetic=== "Ambrosian Oaks" set to the [[Finlandia Hymn]] is the school song of [[St. Ambrose University]] in [[Davenport, Iowa]]. There is a [[proverb]], "Mighty oaks from little [[acorn]]s grow." Another is: "Every majestic oak tree was once a nut who stood his ground." Many woods are connected to certain birth months, according to the Irish, and oak is the wood of June/July. However, in some variations, rosewood has been known to be June's wood {{Fact|date=February 2007}}. ===Names=== [[Oakland]], California. The area was called ''encinal'' by the original Spanish colonizers, a word which means "oak grove," and the origin of the city's name. It was so dubbed, because of a large stand of oak forest that differentiated it from the surrounding region. [[Raleigh, NC|Raleigh]], [[North Carolina]] has been nicknamed the "City of Oaks." The [[Romania national rugby union team]] is nicknamed ''The Oaks.'' ==Historical note on Linnaean species== [[Carolus Linnaeus|Linnaeus]] described only five species of oak from eastern North America, based on general leaf form. These were [[White oak]], ''Q. alba'', [[Chestnut oak]], ''Q. Montana'', [[List_of_Quercus_species#Section_Lobatae|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 with only the specimens in Linnaeus' herbarium that refer to the species the names are applied to now. ==References== {{reflist}} * 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. ==Gallery== <gallery> Image:Raunkiaer.jpg|A [[Pedunculate oak]] in [[Denmark]] Image:Oak_at_night.JPG|An oak tree at night Image:Oakbark.jpg|Bark of ''[[Quercus robur]]'' Image:Spanish-moss-tree.jpg|[[Southern live oak]] with [[spanish moss]] Image:Quercus mongolica mongolian oak MN 2007.JPG|''Quercus mongolica'' Mongolian Oak in [[Minnesota Landscape Arboretum]] Image:Quercus robur JPG (a).jpg|The oldest oak of the [[Benelux]] in [[Liernu]] ([[Belgium]]). Image:Quercus robur JPG (d2).jpg|The ''Duke Prosper Oak'' in [[Enghien]] ([[Belgium]]). Image:Sivry-Rance AR1aJPG.jpg|''Quercus petraea'' Sessile Oak in [[Sivry-Rance]] ([[Belgium]]). Image:Kindred Spirit® Hybrid Oak.jpg|Form of [[Kindred Spirit Hybrid Oak]]. </gallery> ==See also== * [[List of plants poisonous to equines]] ==External links== {{commonscat|Quercus}} {{Wikispecies|Quercus}} * [http://flora.huh.harvard.edu:8080/flora/browse.do?flora_id=1&taxon_id=127839 Flora of North America: ''Quercus''] * [http://flora.huh.harvard.edu:8080/flora/browse.do?flora_id=2&taxon_id=127839 Flora of China: ''Quercus''] * [http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=108828 ''Flora of China'' - ''Cyclobalanopsis''] *[http://rbg-web2.rbge.org.uk/cgi-bin/nph-readbtree.pl/feout?FAMILY_XREF=&GENUS_XREF=Quercus&SPECIES_XREF=&TAXON_NAME_XREF=&RANK= Flora Europaea: ''Quercus''] *[http://www.bcgov.net/bftlib/oaktrees.htm Oak Trees of the Lowcountry (South Carolina) -- Beaufort County Library] * [http://www.deby.bialowieza.pl/ang/index.php5 Oaks from Bialowieza Forest](English) [[Category:Quercus]] [[Category:Fagaceae]] [[ang:Āc]] [[ar:سنديان]] [[an:Caxico]] [[be:Дуб]] [[bar:Oach]] [[bg:Дъб]] [[ca:Roure]] [[cv:Юман]] [[cs:Dub]] [[cy:Derwen]] [[da:Eg]] [[de:Eichen]] [[el:Βελανιδιά]] [[eml:Quérza]] [[es:Roble]] [[eo:Kverko]] [[eu:Haritz]] [[fa:بلوط]] [[fr:Chêne]] [[gl:Carballo (árbore)]] [[ko:참나무]] [[hsb:Dub]] [[hr:Hrast]] [[id:Ek]] [[ia:Quercus]] [[it:Quercus]] [[he:אלון]] [[kw:Derow]] [[ht:Chèn]] [[la:Quercus]] [[lv:Ozoli]] [[lb:Eechen]] [[lt:Ąžuolas]] [[li:Eik]] [[hu:Tölgy]] [[nah:Teōcuahuitl]] [[nl:Eik]] [[nds-nl:Eek (boom)]] [[ja:オーク]] [[ka:მუხა]] [[no:Eik]] [[nn:Eik]] [[nrm:Tchêne]] [[oc:Quercus]] [[pl:Dąb]] [[pt:Carvalho]] [[ru:Дуб]] [[simple:Oak]] [[sk:Dub]] [[sl:Hrast]] [[sr:Храст]] [[fi:Tammet]] [[sv:Eksläktet]] [[chr:ᏧᏍᎦ]] [[tr:Meşe]] [[uk:Дуб]] [[wa:Tchinne (åbe)]] [[vls:Êke]] [[zh:櫟屬]]