See List of Quercus species. There are approximately extant species of oaks.
The common name "oak" also appears in the of species in related genera, notably Lithocarpus stone oaksas 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 species of which are endemic. The second greatest center of Mature red oak tree diversity is China, which contains approximately species. Oaks have spirally arranged leaves,
Mature red oak tree 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 Mature red oak tree. The acorns and leaves contain tannic acid which helps to guard from fungi and insects. The oak tree is a flowering plant. Oaks may be divided into two genera sometimes referred to as subgenera and a number of sections:.
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 Quercussection Quercus ; see List of Quercus species. Inter-section hybrids, except between species of sections Quercus and Mesobalanusare unknown.
Recent systematic studies appear to confirm a Mature red oak tree 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 Mature red oak tree offspring.
Frequent hybridization among oaks has consequences for oak populations around the world; most notably, hybridization has produced large populations of hybrids with
Mature red oak tree amounts of introgressionand the evolution of new species.
Mature red oak tree wood has a density of about 0. 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 Mature red oak tree green logs, by axe and wedge, to produce radial planks, similar to quarter-sawn timber. Wide, quarter-sawn boards of oak have been prized since the Middle Ages for use in interior panelling of prestigious buildings such as the debating chamber of the House of Commons in Mature red oak tree and in the construction of fine furniture. Oak wood, from Quercus robur and Quercus petraeawas used in Europe for the construction of shipsespecially naval men of war until the 19th century, and was the principal timber used in the construction Mature red oak tree European timber-framed buildings.
Today oak Mature red oak tree is still commonly used for furniture making and flooring, timber frame buildings, and production.
Barrels in which winessherryand spirits such as brandyIrish whiskeyScotch 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 Mature red oak tree 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 roburQ. 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 Mature red oak tree other foods. Japanese oak is used in Mature red oak tree making of professional drums from the manufacturer Yamaha Mature red oak tree. 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 Mature red oak tree making agricultural implements. The leaves are used as fodder during lean period and bedding for livestock. The bark of the cork oak is used
Mature red oak tree produce wine stoppers corks. This species grows in the Mediterranean Sea region, with PortugalSpainAlgeriaand 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 oaks prevents them from absorbing preservatives. These openings give fungus easy access when the finish deteriorates. Shumard oaka member of the red
Mature red oak tree subgenus, provides timber which is described Mature red oak tree "mechanically superior" to
Mature red oak tree red oak.
Cherrybark oak is another type of red oak which provides excellent timber. The standard the lumber 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 sessile oak accounts for most of the European Mature red oak tree production, but evergreen species, such as Holm oak and cork oak also produce valuable timber.
The bark of the white oak is dried and used in medical preparations. Oak bark is also rich in tannin
Mature red oak tree 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 a main ingredient in iron gall inka kind of Mature red oak tree ink, harvested at a specific time Mature red oak tree
Mature red oak tree. 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 the Ericaceae in oak—heath forests.
Similarly many other mushrooms such as Ramaria flavosaponaria also associate with oaks. Many species of oaks are under threat of extinction in the wild, largely Mature red oak tree to land use changes, livestock grazing and unsustainable harvesting. For example, over the past years, large areas of oak forest in the highlands of Mexico, Central America and the Mature red oak tree 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 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, species of oak trees include scarlet oak Quercus coccineachinkapin oak Quercus muehlenbergiiand 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
Mature red oak tree effectiveness of the overproduction in the mast year that follows. Beginning November 1,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. The project is still in the process of annotating this genome.
Sudden oak death Phytophthora ramorum is a water mould that can kill oaks within just a few weeks. Oak wiltcaused the fungus Ceratocystis fagacearum a fungus closely related to Dutch elm diseaseis also a lethal disease of some oaks, particularly the red oaks the white oaks can be infected but generally Mature red oak tree longer.
Other dangers include wood-boring beetlesas well as root rot
Mature red oak tree older trees which may not be apparent on the outside, often being discovered only when 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 Mature red oak tree of Lepidoptera butterfly and moth species such as the gypsy mothLymantria disparwhich can defoliate 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 galloak marble galloak apple gall, knopper galland 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
Mature red oak tree of mature oaks, acute oak declinehas
Mature red oak tree reported Mature red oak tree parts of the UK since Oak processionary moth Thaumetopoea processionea has become a Mature red oak tree threat in the UK since 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 respiratory problems.
In California, oaks are affected by the fungal disease Foamy bark canker. The leaves and acorns of the oak tree are poisonous to cattlehorsessheepand goats in large amounts due to the toxin tannic acidand cause kidney damage and gastroenteritis. Symptoms of poisoning include lack of appetitedepression, constipation, diarrhea which may contain bloodblood in urineand colic.
The exception to livestock and oak toxicity is the domestic pigwhich 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 of pannage for hundreds of years. Acorns are also edible to humans, after leaching of the tannins. The oak is a common symbol of strength and endurance and has been chosen Mature red oak tree the national tree of many countries.
Already an ancient Mature red oak tree symbol in the form of the Donar Oakfor
The oak is the emblem of County Londonderry in Northern Irelandas 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 Derrywhich originally in Irish was known as Doire meaning oak. Iowa designated the oak as its official state tree in ; and the White Oak is the state
Mature red oak tree of Mature red oak treeIllinois and Maryland.
The oak is a national symbol from the Basque Countryspecially in the province of Biscay. The coat-of-arms of the municipality EigersundNorway features an oak leaf. Oak leaves are traditionally an important Mature red oak tree of German Army regalia. It is also known as the Eagle. They also symbolize rank in the United States Armed Forces. A Mature red oak tree oak leaf indicates an O-4 Major or Lt.
Commanderwhereas a silver oak leaf indicates an O-5 Lt.
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