See List of Quercus species
An oak is a tree or shrub in the genus Quercus (/ˈkwɜːrkəs/;
Latin "oak tree") of the beech family, Fagaceae. There are
approximately 600 extant species of oaks. The common name "oak" also
appears in the names of species in related genera, notably Lithocarpus
(stone oaks), as well as in those of unrelated species such as
Grevillea robusta (silky oaks) and the
Casuarinaceae (she-oaks). The
genus Quercus is native to the Northern Hemisphere, and includes
deciduous and evergreen species extending from cool temperate to
tropical latitudes in the Americas, Asia, Europe, and North Africa.
North America contains the largest number of oak species, with
approximately 90 occurring in the United States, while
Mexico has 160
species of which 109 are endemic. The second greatest center of oak
diversity is China, which contains approximately 100 species.
Oaks have spirally arranged leaves, with lobate margins in many
species; some have serrated leaves or entire leaves with smooth
margins. Many deciduous species are marcescent, not dropping dead
leaves until spring. In spring, a single oak tree produces both male
flowers (in the form of catkins) and small female flowers. The
fruit is a nut called an acorn or oak nut 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 their
species. The acorns and leaves contain tannic acid, which helps to
guard from fungi and insects. The live oaks are distinguished for
being evergreen, but are not actually a distinct group and instead are
dispersed across the genus.
4 Biodiversity and ecology
6 Diseases and pests
8 Cultural significance
8.1 National symbol
8.1.1 Oaks as regional and state symbols
8.1.2 Political use
8.4 Famous oak trees
9 Historical note on Linnaean species
10 See also
13 External links
The oak tree is a flowering plant. Oaks may be divided into two genera
(sometimes referred to as subgenera) and a number of sections:
Oak at Schönderling
See also: List of Quercus species
The genus 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
an acorn shell is hairless. The leaves mostly lack a bristle on their
lobe tips, which are usually rounded. The type species is Quercus
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 this acorn's shell is hairless. The section
closely related to section Quercus and sometimes included in it.
Sect. Cerris, the Turkey oak and its relatives of
Europe and Asia.
Styles long; acorn mature in 18 months and taste very bitter. The
inside of the acorn's 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
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
Old oak tree on the shore of Lake Koluvere, Estonia.
The ring-cupped oaks of eastern and southeastern Asia.
growing 10–40 m (33–131 ft) 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.
Encyclopedia of Life
Encyclopedia of Life and
Flora of China
Flora of China treats
Cyclobalanopsis as a distinct genus, but some taxonomists consider it
a subgenus of Quercus. It contains about 150 species.
Cyclobalanopsis are common in the evergreen subtropical laurel forests
which extend from southern Japan, southern Korea, and Taiwan across
southern China and northern Indochina to the eastern Himalayas, in
association with trees of genus
Castanopsis and the laurel family
A hybrid white oak, possibly
Quercus stellata × Q. muhlenbergii
Interspecific hybridization is quite common among oaks but usually
between species within the same section only 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 hybridization, hybridization produces functional seeds and
fertile hybrid offspring. 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.
Frequent hybridization 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. Frequent hybridization and high levels of
introgression have caused different species in the same populations to
share up to 50% of their genetic information. Having high rates of
hybridization and introgression produces genetic data that often does
not differentiate between two clearly morphologically distinct
species, but instead differentiates populations. 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 phenomenon is still largely a mystery to
The Fagaceae, or beech family, to which the oaks belong, is a very
slow evolving clade compared to other angiosperms, and the
patterns of hybridization and introgression in Quercus pose a great
challenge to the concept of a species since a species is often defined
as a group of “actually or potentially interbreeding populations
which are reproductively isolated from other such groups.” 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.
Heart of oak beams of the frame of Saint-Girons church in Monein,
Oak wood has a density of about 0.75 g/cm3
(0.43 oz/cu in) creating great strength and hardness. The
wood is very resistant to insect and fungal attack because of its high
tannin content. It also has very appealing grain markings,
particularly when quartersawn.
Oak planking was common on high status
Viking longships in the 9th and 10th centuries. The wood was hewn from
green logs, by axe and wedge, to produce radial planks, similar to
quarter-sawn timber. Wide, quarter-sawn boards of oak have been prized
Middle Ages for use in interior panelling of prestigious
buildings such as the debating chamber of the House of Commons in
London 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
Barrels in which wines, sherry, and spirits such as brandy, Irish
Scotch whisky and
Bourbon whiskey are aged are made from
European and American oak, with single barrel whiskey fetching a
premium. 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 the best wines since they
increase the price compared to those aged in American oak wood.
American oak contributes greater texture and resistance to ageing, but
produces more powerful wine bouquets.
Oak wood chips are used for
smoking fish, meat, cheeses, and other foods.
Sherry maturing in oak barrels
Japanese oak is used in the making of professional drums from the
manufacturer Yamaha Drums. The higher density of oak gives the drum a
brighter and louder tone compared to traditional drum materials such
as maple and birch. In hill states of India, besides fuelwood and
timber, the local people use oak wood for making agricultural
implements. The leaves are used as fodder during lean period and
bedding for livestock.
A cross section of the trunk of a cork oak, Quercus suber
The bark of the 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 is one of the most
prized of the red oak group for lumber, much of which is marketed as
red oak regardless of the species of origin. It is not good for
outdoor use due to its open capillaries unless the wood is treated. If
the wood is properly treated with preservatives, it will not rot as
quickly as cured white oak heartwood. The closed cell structure of
white oaks prevents them from absorbing preservatives. With northern
red oak, one can blow air through an end grain piece 10 inches
long to make bubbles come out in a glass of water. These openings give
fungus easy access when the finish deteriorates. Shumard oak, a member
of the red oak subgenus, provides timber which is described as
"mechanically superior" to northern red oak.
Cherrybark oak is another
type of red oak which provides excellent timber.
The standard for the lumber of the white oak group – all of which is
marketed as white oak – is the Quercus alba. White oak is often used
to make wine barrels. The wood of the deciduous pedunculate oak and
sessile oak accounts for most of the European oak production, but
evergreen species, such as
Holm oak and cork oak also produce valuable
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 forest in Estonia.
Oak on sandy earth.
Oak forest on the beach in Njivice, Croatia
Oak galls were used for centuries as a main ingredient in iron gall
ink, a kind of manuscript ink, harvested at a specific time of
year. In Korea, oak bark is used to make shingles for
traditional roof construction.
Biodiversity and ecology
Oaks are keystone species in a wide range of habitats from
Mediterranean semi-desert to subtropical rainforest. For example, oak
trees are important components of hardwood forests, and certain
species are particularly known to grow in associations with members of
Ericaceae in oak-heath forests. A number of kinds of
truffles, including the two well known varieties, the black Périgord
truffle and the white Piedmont truffle, have symbiotic
relationships with oak trees. The
European pied flycatcher
European pied flycatcher is an
example of an animal species that often depends upon oak trees.
Many species of oaks are under threat of extinction in the wild,
largely due to land use changes, livestock grazing and unsustainable
harvesting. For example, over the past 200 years, large areas of oak
forest in the highlands of Mexico,
Central America and the northern
Andes have been cleared for coffee plantations and cattle ranching.
There is a continuing threat to these forests from exploitation for
timber, fuelwood and charcoal. In the USA, entire oak ecosystems
have declined due to a combination of factors still imperfectly known,
but thought to include fire suppression, increased consumption of
acorns by growing mammal populations, herbivory of seedlings, and
introduced pests. In a recent survey, 78 wild oak species have
been identified as being in danger of extinction, from a global total
of over 500 species. The proportion under threat may be much
higher in reality, as there is insufficient information about over 300
species, making it near impossible to form any judgement of their
In the Himalayan region of India, oak forests are being invaded by
pine forests due to the increase in temperature. The associated
species of pine forest may cross frontiers and become new elements of
the oak forests.
In eastern North America, rare species of oak trees include scarlet
oak (Quercus coccinea), chinkapin oak (Quercus muehlenbergii), and
post oak (Quercus stellata).
The mature trees shed varying numbers of acorns annually. Scientists
suggest that shedding excess numbers allows the oaks to satiate nut
gathering species, improving the chances of germination. Every four to
ten years, certain oak populations will synchronize to produce almost
no acorns at all, only to rain them down excessively the following
year, known as a "mast" year. The year preceding the mast year is
thought to starve off the mammal populations feeding on the supply,
thereby increasing the effectiveness of the overproduction in the mast
year that follows. This is necessary to the survival of any
given oak species, as only one in 10,000 acorns results in an eventual
Beginning November 1, 2011, a project began to sequence the entire oak
genome. The goal of the project is to create a high resolution
sequence of the
Quercus robur genome, and to study genetic diversity
by comparison of the genomes of different species. Current
research has compiled genomic data from many different sources and
techniques to create a genome map with 89% coverage of the genome. The
project is still in the process of annotating this genome.
Diseases and pests
See also: List of
Lepidoptera that feed on oaks
Oak powdery mildew on pedunculate oak
Sudden oak death
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 being discovered
only 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.
A considerable number of galls are found on oak leaves, buds, flowers,
roots, etc. Examples are oak artichoke gall, oak marble gall, oak
apple gall, knopper gall, and spangle gall.
A number of species of fungus cause powdery mildew on oak species. In
Europe the species
Erysiphe alphitoides is the most common cause.
A new and yet little understood disease of mature oaks, acute oak
decline, has been reported in parts of the UK since 2009.
Oak processionary moth (Thaumetopoea processionea) has become a
serious threat in the UK since 2006. The caterpillars of this species
defoliate the trees, and are hazardous to human health; their bodies
are covered with poisonous hairs which can cause rashes and
In California, oaks are affected by the fungal disease Foamy bark
The leaves and acorns of the oak tree are poisonous to cattle, horses,
sheep, and goats in large amounts due to the toxin tannic acid, and
cause kidney damage and gastroenteritis. Symptoms of poisoning include
lack of appetite, depression, constipation, diarrhea (which may
contain blood), blood in urine, and colic. The exception to livestock
and oak toxicity is the domestic pig, which may be fed entirely on
acorns in the right conditions, and has traditionally been pastured in
oak woodlands (such as the Spanish dehesa and the English system of
pannage) for hundreds of years.
Acorns are also edible to humans, after leaching of the tannins.
Oak branches on the coat of arms of Estonia
The oak is a common symbol of strength and endurance and has been
chosen as the national tree of many countries. Already an ancient
Germanic symbol (in the form of the Donar Oak, for instance),
certainly since the early nineteenth century, it stands for the nation
Germany and oak branches are thus displayed on some German coins,
both of the former
Deutsche Mark and the current
Euro currency. In
2004 the Arbor Day Foundation held a vote for the official
Tree of the
United States of America. In November 2004, the
United States Congress passed legislation designating the oak as
America's National Tree.
Other countries have also designated the oak as their national tree
Cyprus (Golden Oak), England, Estonia, France,
Germany, Moldova, Jordan, Latvia, Lithuania, Poland, Romania, Serbia,
Oaks as regional and state symbols
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.
County Kildare derives its name from the town of Kildare
which originally in Irish was Cill Dara meaning the Church of the Oak
Iowa designated the oak as its official state tree in 1961; and the
Oak is the state tree of Connecticut,
Illinois and Maryland. The
Northern Red Oak
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, USA.
The oak is a national symbol from the Basque Country, specially in the
province of Biscay.
The oak is a symbol of the East Bay of the San Francisco Bay Area; the
coat-of-arms and flag of
Oakland, California feature the oak and the
logo of the
East Bay Regional Park District
East Bay Regional Park District is an oak leaf.
The coat-of-arms of Vest-Agder, Norway, and Blekinge, Sweden, features
The coat-of-arms of the municipality Eigersund,
Norway features an oak
Oak leaves are traditionally an important part of German Army
regalia. The Nazi party used the traditional German
eagle, standing atop of a swastika inside a wreath of oak leaves. It
is also known as the Iron Eagle. During the Third Reich of Nazi
Germany, oak leaves were used for military valor decoration on the
Knights Cross of the Iron Cross. 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
Oak leaves are embroidered onto the covers (hats) worn
by field grade officers and flag officers in the
United States armed
If a member of the
United States Army or Air Force earns multiple
awards of the same medal, then instead of wearing a ribbon or medal
for each award, he or she wears one metal representation of an "oak
leaf cluster" attached to the appropriate ribbon for each subsequent
The oak tree is used as a symbol by a number of political parties. It
is the symbol of Toryism (on account of the Royal Oak) and the
Conservative Party in the United Kingdom, and formerly of the
Progressive Democrats in Ireland and the
Democrats of the Left
Democrats of the Left in
Italy. In the cultural arena, the oakleaf is the symbol of the
National Trust (UK), The Woodland Trust, and The Royal Oak
Grīdnieku ancient oak in Rumbas parish, Latvia, girth 8.27m, 2015
In Greek mythology, the oak is the tree sacred to Zeus, king of the
gods. In Zeus's oracle in Dodona, Epirus, the sacred oak was the
centerpiece of the precinct, and the priests would divine the
pronouncements of the god by interpreting the rustling of the oak's
In Baltic and Slavic mythology, the oak is the sacred tree of Latvian
Pērkons, Lithuanian Perkūnas, Prussian Perkūns and Slavic
Perun, the god of thunder and one of the most important deities in
the Baltic and Slavic pantheons.
In Celtic polytheism, the name of the oak tree was part of the
Proto-Celtic word for 'druid': *derwo-weyd- > *druwid- ;
however, Proto-Celtic *derwo- (and *dru-) can also be adjectives for
'strong' and 'firm', so Ranko Matasovic interprets that *druwid- may
mean 'strong knowledge'. As in other Indo-European faiths, Taranis,
being a thunder god, was associated with the oak tree. The
Indo-Europeans worshiped the oak and connected it with a thunder or
lightning god; "tree" and drus may also be cognate with "Druid," the
Celtic priest to whom the oak was sacred. There has even been a study
that shows that oaks are more likely to be struck by lightning than
any other tree of the same height.
In Norse mythology, the oak was sacred to the thunder god, Thor.
Thor's Oak was a sacred tree of the Germanic
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." Absalom's long hair (2 Samuel 18:9) gets
caught in an oak tree, and allows Joab to kill him.
The badnjak is central tradition in
Serbian Orthodox Church
Serbian Orthodox Church Christmas
celebration where young and straight oak, is ceremonially felled early
on the morning of
In some traditions of Wicca, the
Oak King is one of the two faces of
the Sun God. He is born on Yule and rules from Ostara to
Several singular 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.
Approximately 50 km west of Toronto, Canada is the town of
Oakville, ON, famous for its history as a shipbuilding port on Lake
The city of Raleigh, N.C., is known as "The City of Oaks."
Jurupa Oak tree – a clonal colony of Quercus palmeria or
Palmer’s oak found in Riverside County, California – is an
estimated 13,000 years old.
Large groups of very old oak trees are rare[why?]. One of the oldest
groups of oak trees, found in Poland, is about 480 years old, which
was assessed by dendrochronological methods.
In the Roman Republic, a crown of oak leaves was given to those who
had saved the life of a citizen in battle; it was called the "civic
Famous oak trees
Main article: List of notable trees
Tamme-Lauri oak is the thickest and oldest tree in Estonia.
The Big Oak, by
Gustave Courbet (1843).
Emancipation Oak is designated one of the 10 Great Trees of the
World by the National Geographic Society and is part of the National
Historic Landmark district of Hampton University.
Ivenack Oak which is one of the largest trees in
Europe is located
in Mecklenburg-Vorpommern, Germany, and is approximately 800 years
The Bowthorpe Oak, located in Bourne, Lincolnshire, is thought to be
1,000 years old. It was featured in the Guinness Book of World Records
and was filmed for a TV documentary for its astonishing longevity.
The Minchenden (or Chandos) Oak, in Southgate, London, is said to be
the largest oak tree in
England (already 27 feet or 8.2 meters in
girth in the nineteenth century), and is perhaps 800 years old.
Seven Sisters Oak
Seven Sisters Oak is the largest certified southern live oak tree.
Located in Mandeville, Louisiana, it is estimated to be up to 1,500
years old with a trunk that measures 38 ft (11.6 meters).
Major Oak is an 800 to 1000-year-old tree located in Sherwood
Forest, Nottinghamshire. According to folklore, it was used by Robin
Hood for shelter.
Oak is a 500-year-old southern live oak located in Long
Oak is believed to have originated in the 11th Century and
is located in Addlestone, Surrey. It is an important symbol of the
town with many local businesses adopting its name. It used to mark the
boundary of Windsor Great Park. Legend says that Queen Elizabeth I
stopped by it and had a picnic.
Angel Oak is a southern live oak located in
Angel Oak Park on
John's Island near Charleston, South Carolina. The
Angel Oak is
estimated to be in excess of 400–500 years old, stands 66.5 ft
(20.3 m) tall, and measures 28 ft (8.5 m) in
The Kaiser's Oak, located at the village of Gommecourt in Artois,
France, named in honour of Kaiser Wilhelm II, symbolically marked from
late 1914 to April 1917 the furthest point in the West of the German
Imperial Army during World War One.
Wye Oak in
Maryland was the United States' largest white oak tree
before it blew down in a storm in 2002, at an estimated age of 460
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. montana and Q. rubra specimens actually
included mixed foliage of more than one species.
List of Quercus species
^ Sunset Western Garden Book, 1995, Leisure Arts, pp. 606–607,
^ Hogan, C. Michael (2012)
Oak Archived 23 May 2013 at the Wayback
Machine.. ed. Arthur Dawson. Encyclopedia of Earth. National Council
for Science and the Environment. Washington DC
^ Conrad, Jim. "
Oak Flowers" Archived 4 November 2013 at the Wayback
Machine.. backyardnature.com. 2011-12-12. Retrieved 2013-11-03.
^ Tull, Delena (1 January 1999). Edible and Useful Plants of Texas and
the Southwest: A Practical Guide. University of Texas Press.
ISBN 9780292781641. Archived from the original on 15 February
^ Hipp, Andrew (2004).
Oak Trees Inside and Out. Rosen Publishing
Group, Inc. p. 4.
^ a b Williams, Joseph H.; Boecklen, William J.; Howard, Daniel J.
(2001). "Reproductive processes in two oak (Quercus) contact zones
with different levels of hybridisation". Heredity. 87 (6): 680–690.
^ Arnold, M. L. (1997). Natural Hybridization and Evolution. New York:
Oxford University Press. ISBN 0-19-509974-5.
^ Conte, L.; Cotti, C.; 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.
^ Gomory, D.; Schmidtova, J. (2007). "Extent of nuclear genome sharing
among white oak species (Quercus L. subgen.
Oerst.) in Slovakia estimated by allozymes".
Plant Systematics and
Evolution. 266 (3–4): 253–264.
^ Kelleher, C. T.; Hodkinson, T. R.; Douglas, G. C.; Kelly, D. L.
Species distinction in Irish populations of Quercus petraea
and Q. robur: Morphological versus molecular analyses". Annals of
Botany. 96 (7): 1237–1246. doi:10.1093/aob/mci275.
^ Frascaria, N.; Maggia, L.; Michaud, M.; Bousquet, J. (1993). "The
RBCL Gene Sequence from
Chestnut Indicates a Slow Rate of Evolution in
the Fagaceae". Genome. 36 (4): 668–671. doi:10.1139/g93-089.
^ Manos, P. S.; Stanford, A. M. (2001). "The historical biogeography
of Fagaceae: Tracking the tertiary history of temperate and
subtropical forests of the Northern Hemisphere". International Journal
Plant Sciences. 162 (Suppl. 6): S77–S93.
^ Raven, Peter H.; Johnson, George B.; Losos, Jonathan B.; Singer,
Susan R. (2005). Biology (Seventh ed.). New York: McGraw Hill.
^ Baugh, Daniel A. (1965). British Naval Administration in the Age of
Walpole. Princeton University Press. p. 242.
^ Cheese. swaledalecheese.co.uk
^ Kala, C.P. (2004). Studies on the indigenous knowledge, practices
and traditional uses of forest products by human societies in
Uttarakhand state of India. GBPIHED, Almora, India
^ Kala, C.P. (2010). Medicinal Plants of Uttarakhand: Diversity
Livelihood and Conservation. BioTech Books, Delhi,
^ The Natural Communities of Virginia Classification of Ecological
Community Groups (Version 2.3), Virginia Department of Conservation
and Recreation, 2010 Archived 15 January 2009 at the Wayback Machine..
Dcr.virginia.gov. Retrieved on 2011-12-10.
^ Schafale, M. P. and A. S. Weakley. 1990. Classification of the
natural communities of North Carolina: third approximation. North
Carolina Natural Heritage Program, North Carolina Division of Parks
^ "Truffle Glossary: Black Truffles". thenibble.com. 1 July 2010.
Archived from the original on 19 April 2010. Retrieved 1 July
^ "Truffle Glossary: White Truffles". thenibble.com. 1 July 2010.
Archived from the original on 25 September 2010. Retrieved 1 July
^ Kappelle, M. (2006). "Neotropical montane oak forests: overview and
outlook", pp 449–467 in: Kappelle, M. (ed.). Ecology and
conservation of neotropical montane oak forests. Ecological Studies
No. 185. Springer-Verlag, Berlin, doi:10.1007/3-540-28909-7_34
^ Lorimer, C.G. (2003) Editorial: The decline of oak forests Archived
17 March 2014 at the Wayback Machine.. American Institute of
^ Oldfield, S. & Eastwood, A. (2007) The Red List of Oaks Flora
& Fauna International (FFI) and Botanic Gardens Conservation
International (BGCI) ISBN 978-1-903703-25-0
^ Kala, C.P. (2012). Biodiversity, communities and climate change.
Teri Publications, New Delhi, ISBN 817993442X.
^ Carpenter, Paul (1990). Plants in the Landscape. New York: W.H.
Freeman and Company. p. 73. ISBN 0716718081.
^ "Up to your ankles in acorns? Here's why". The Mercury News. 13
October 2007. Archived from the original on 28 December 2017.
Retrieved 28 December 2017.
^ "What's causing an abundance of acorns this year?". The Mercury
News. 6 October 2016. Archived from the original on 28 December 2017.
Retrieved 28 December 2017.
^ Waymer, Jim (3 December 2016). "That's nuts:
Acorn onslaught hits
Florida". Florida Today. Melbourne, Florida. pp. 1A, 11A.
Archived from the original on 29 December 2016. Retrieved 3 December
^ "Quercus Portal". Archived from the original on 29 December 2016.
Retrieved 3 December 2016.
^ Plomion, C., Aury, J.-M., Amselem, J., Alaeitabar, T., Barbe, V.,
Belser, C., Bergès, H., Bodénès, C., Boudet, N., Boury, C.,
Canaguier, A., Couloux, A., Da Silva, C., Duplessis, S., Ehrenmann,
F., Estrada-Mairey, B., Fouteau, S., Francillonne, N., Gaspin, C.,
Guichard, C., Klopp, C., Labadie, K., Lalanne, C., Le Clainche, I.,
Leplé, J.-C., Le Provost, G., Leroy, T., Lesur, I., Martin, F.,
Mercier, J., Michotey, C., Murat, F., Salin, F., Steinbach, D.,
Faivre-Rampant, P., Wincker, P., Salse, J., Quesneville, H. and
Kremer, A. (2016), Decoding the oak genome: public release of sequence
data, assembly, annotation and publication strategies. Mol Ecol
Resour, 16: 254–265. doi:10.1111/1755-0998.12425
Oak Insects and Diseases: Gypsy Moth". TreeHelp.com.
Archived from the original on 7 July 2010. Retrieved 27 April
^ Mougou, A.; Dutech, C.; Desprez-Loustau, M. -L. (2008). "New
insights into the identity and origin of the causal agent of oak
powdery mildew in Europe". Forest Pathology. 38 (4): 275.
^ Kinver, Mark (28 April 2010). "
Oak disease 'threatens landscape'".
BBC News. Archived from the original on 29 April 2010. Retrieved 29
^ "Invasion of toxic moths". The Northern Echo. July 10, 2012.
^ Bainbridge, D. A. (12–14 November 1986), Use of acorns for food in
California: past, present and future, San Luis Obispo, CA.: Symposium
on Multiple-use Management of California's Hardwoods, archived from
the original on 27 October 2010
^ Schierz, Kai Uwe (2004). "Von Bonifatius bis Beuys, oder: Vom Umgang
mit heiligen Eichen". In Hardy Eidam; Marina Moritz; Gerd-Rainer
Riedel; Kai-Uwe Schierz. Bonifatius: Heidenopfer, Christuskreuz,
Eichenkult (in German). Stadtverwaltung Erfurt.
^ "Trees – Arbor Day Foundation". Arborday.org. Archived from the
original on 28 April 2010. Retrieved 27 April 2010.
Oak Trees". arborday.org. Archived from the original on 9 January
2010. Retrieved 27 April 2010.
Oak as a Symbol". Venables Oak. Archived from the original on 5 May
2013. Retrieved 26 September 2012.
^ a b "Political or Symbolic". Extended Definition: oak. Archived from
the original on 30 May 2013. Retrieved 26 September 2012.
^ "Army Regulation 670-1 Wear of appurtenances Section 29.12 Page
278". ar670.com. Archived from the original on 22 January 2018.
Retrieved 19 January 2018. CS1 maint: BOT: original-url status
^ Pickles, Eric. "The Conservative Party". Conservatives.com. Archived
from the original on 29 April 2010. Retrieved 27 April 2010.
^ Coalition Government 1989 To 1992. progressivedemocrats.ie
^ Frazer, James George (1922). The Golden Bough. Chapter XV: The
Worship of the Oak. Archived 21 May 2012 at the Wayback Machine.
^ "Ąžuolas paprastasis". Zolininkas.lt (in Lithuanian). 21 February
2011. Retrieved 10 January 2018.
^ Taylor, John W. (September 1979). "
Tree Worship" Archived 17 March
2014 at the Wayback Machine., Mankind Quarterly, pp. 79–142.
^ a b Oak. A Dictionary of Literary Symbols. Cambridge.
^ Millais, J.G. (1899) Life and Letters of Sir John Everett Millais,
vol. 1, p. 166, London : Methuen.
^ Arborecology, containing a photograph of the Millais oak Archived 28
August 2008 at the Wayback Machine.. arborecology.co.uk
^ Yong, Ed. "The 13,000-year old tree that survives by cloning
itself". www.nationalgeographic.com. Archived from the original on 6
March 2016. Retrieved 3 February 2016.
^ Ufnalski K. The oldest groups of oak trees in Poland. Proceedings of
EuroDendro 2008 "The long history of wood utilization" News of Forest
History Nr. V (39)/2008:83–84
^ a b Bermosa, Nobert. "Famous
Oak Trees in the World". Archived from
the original on 17 August 2012. Retrieved 30 September 2012.
^ "Geograph:: Minchenden Oak, Garden of Remembrance,... (C) Christine
Matthews". Archived from the original on 29 December 2016. Retrieved 3
Seven Sisters Oak
Seven Sisters Oak Archived 11 October 2012 at the Wayback Machine..
^ "Seven Sisters Oak". 100 Oaks Project. 4 December 2009. Archived
from the original on 19 July 2012.
Byfield, Liz (1990) An oak tree, Collins book bus, London :
Collins Educational, ISBN 0-00-313526-8
Philips, Roger. Trees of
North America and Europe, Random House, Inc.,
New York ISBN 0-394-50259-0, 1979.
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.
Żukow-Karczewski, Marek (1988) Dąb – król polskich drzew (
the king of the Polish trees), AURA (A Monthly for the protection and
shaping of human environment), 9, 20–21.
Wikimedia Commons has media related to Quercus.
Wikispecies has information related to Quercus
Flora of China
Flora of China – Cyclobalanopsis
Flora Europaea: Quercus
Oaks from Bialowieza Forest
Common Oaks of Florida
Oaks of the world
The Global Trees Campaign The Red List of Oaks and Global Survey of
Latvia – the land of oaks
Janka Hardness Scale – The Janka Hardness Scale for many Exotic and
Eichhorn, Markus (May 2010). "
Oak – A Very English Tree". Test Tube.
Brady Haran for the University of Nottingham.
Sources of tannins
Areca catechu seed
Myrtan or black marlock
Tanner's sumach leaves -
Rhus coriaria or Chinese gall on Rhus
General : Tanbark
Acacias (most notably
Acacia pycnantha and Acacia decurrens)
Prosopis sp. bark and wood
Tizra heartwood and root
Anadenanthera colubrina (vilca)
National symbols of the United States
Flag of the United States
Seal of the United States
General Grant (tree)
Pledge of Allegiance
"The Star-Spangled Banner"
"America the Beautiful"
"The Stars and Stripes Forever"
"Hail to the Chief"
"My Country, 'Tis of Thee"
"God Bless America"
"Lift Every Voice and Sing"
"The Army Goes Rolling Along"
"The Air Force Song"
"The Washington Post March"
"Battle Hymn of the Republic"
"You're a Grand Old Flag"
"When Johnny Comes Marching Home"
"This Land Is Your Land"
In God We Trust
E Pluribus Unum
Novus ordo seclorum
Statue of Liberty
Statue of Liberty (Liberty Enlightening the World)
West Potomac Park
Bow and arrow
Cedar (Calocedrus, Cedrus)
Linden (lime, basswood)
Crown of thorns
Mortise and tenon
Tongue and groove
American Association of Woodturners
Architectural Woodwork Institute
Wood Workers' International
Caricature Carvers of America
International Federation of Building and
Wood Carvers Association
Timber Framers Guild
Frame and panel