26-509: Carvalho ( Portuguese pronunciation: [kɐɾˈvaʎu] ), meaning ' oak ', is a Portuguese surname . Origin: Celtic toponymic, from (s)kerb(h) / karb (hard, twisted). The surname is most common in Portugal , Brazil , Galicia (although in Galicia it may be spelled ' Carvallo ' or ' Carballo '), the former Portuguese African colonies ( Angola , Mozambique , etc.), people from
52-825: A cup. The genus is widely distributed in the Northern Hemisphere; it includes some 500 species, both deciduous and evergreen . Fossil oaks date back to the Middle Eocene . Molecular phylogeny shows that the genus is divided into Old World and New World clades , but many oak species hybridise freely, making the genus's history difficult to resolve. Ecologically, oaks are keystone species in habitats from Mediterranean semi-desert to subtropical rainforest . They live in association with many kinds of fungi including truffles . Oaks support more than 950 species of caterpillar , many kinds of gall wasp which form distinctive galls , roundish woody lumps such as
78-633: A narrow belt along the Himalayas to cover mainland and island Southeast Asia as far as Sumatra , Java , Borneo , and Palawan . Finally, oaks of multiple sections ( Cyclobalanopsis , Ilex , Cerris , Quercus and related genera like Lithocarpus and Castanopsis ) extend across east Asia including China, Korea, and Japan. Potential records of Quercus have been reported from Late Cretaceous deposits in North America and East Asia. These are not considered definitive, as macrofossils older than
104-485: A range of flavours, colours, and aromas. The spongy bark of the cork oak is used to make traditional wine bottle corks. Almost a third of oak species are threatened with extinction due to climate change, invasive pests , and habitat loss . In culture, the oak tree is a symbol of strength and serves as the national tree of many countries. In Indo-European and related religions, the oak is associated with thunder gods . Individual oak trees of cultural significance include
130-508: A single oak tree produces both staminate ('male') flowers in the form of catkins , and small pistillate ('female') flowers, meaning that the trees are monoecious . The fruit is a nut called an acorn , borne in a cup-like structure known as a cupule ; each acorn usually contains one seed and takes 6–18 months to mature, depending on the species. The acorns and leaves contain tannic acid , which helps to guard against fungi and insects. There are some 500 extant species of oaks. Trees in
156-557: A small area of the west of Cuba ; in Mesoamerica it occurs mainly above 1000 metres. The genus crossed the isthmus of Panama when the northern and southern continents came together and is present as one species, Q. humboldtii , above 1000 metres in Colombia. The oaks of North America are of many sections ( Protobalanus , Lobatae , Ponticae , Quercus , and Virentes ) along with related genera such as Notholithocarpus . In
182-567: Is wood from angiosperm trees . These are usually found in broad-leaved temperate and tropical forests . In temperate and boreal latitudes they are mostly deciduous , but in tropics and subtropics mostly evergreen . Hardwood (which comes from angiosperm trees) contrasts with softwood (which is from gymnosperm trees). Hardwoods are produced by angiosperm trees that reproduce by flowers, and have broad leaves. Many species are deciduous. Those of temperate regions lose their leaves every autumn as temperatures fall and are dormant in
208-450: Is due to the variety of characteristics apparent in different timbers, including density, grain, pore size, growth and fibre pattern, flexibility and ability to be steam bent. For example, the interlocked grain of elm wood ( Ulmus spp.) makes it suitable for the making of chair seats where the driving in of legs and other components can cause splitting in other woods. There is a correlation between density and calories/volume. This makes
234-452: Is from Old English ac (seen in placenames such as Acton , from ac + tun , "oak village" ), which in turn is from Proto-Germanic *aiks , "oak". Oaks are hardwood ( dicotyledonous ) trees, deciduous or evergreen, with spirally arranged leaves , often with lobate margins ; some have serrated leaves or entire leaves with smooth margins. Many deciduous species are marcescent , not dropping dead leaves until spring. In spring,
260-453: Is rich in phenolic compounds, such as stilbenes , lignans , norlignans, tannins , flavonoids . Hardwoods are employed in a large range of applications, including fuel , tools , construction , boat building , furniture making, musical instruments , flooring , cooking , barrels , and manufacture of charcoal . Solid hardwood joinery tends to be expensive compared to softwood. In the past, tropical hardwoods were easily available, but
286-433: Is the presence of pores, or vessels . The vessels may show considerable variation in size, shape of perforation plates (simple, scalariform, reticulate, foraminate), and structure of cell wall, such as spiral thickenings. As the name suggests, the wood from these trees is generally harder than that of softwoods, but there are significant exceptions. In both groups there is an enormous variation in actual wood hardness, with
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#1732765873968312-643: The Paleogene , and possibly from before the Eocene are mostly poorly preserved without critical features for certain identification. Amongst the oldest unequivocal records of Quercus are pollen from Austria, dating to the Paleocene -Eocene boundary, around 55 million years ago. The oldest records of Quercus in North America are from Oregon , dating to the Middle Eocene, around 44 million years ago, with
338-853: The Royal Oak in Britain, the Charter Oak in the United States, and the Guernica Oak in the Basque Country . The generic name Quercus is Latin for "oak", derived from Proto-Indo-European *kwerkwu- , "oak", which is also the origin of the name " fir ", another important or sacred tree in Indo-European culture. The word "cork", for the bark of the cork oak , similarly derives from Quercus . The common name "oak"
364-436: The oak apple , and a large number of pests and diseases. Oak leaves and acorns contain enough tannin to be toxic to cattle, but pigs are able to digest them safely. Oak timber is strong and hard, and has found many uses in construction and furniture-making. The bark was traditionally used for tanning leather . Wine barrels are made of oak; these are used for aging alcoholic beverages such as sherry and whisky , giving them
390-706: The Old World, oaks of section Quercus extend across the whole of Europe including European Russia apart from the far north, and north Africa (north of the Sahara) from Morocco to Libya. In Mediterranean Europe, they are joined by oaks of the sections Cerris and Ilex , which extend across Turkey, the Middle East, Iran, Afghanistan and Pakistan , while section Ponticae is endemic to the western Caucasus in Turkey and Georgia . Oaks of section Cyclobalanopsis extend in
416-566: The State of Goa , Vasai , a town to the north of Mumbai in India , and also found in the Americas and Asia-Pacific, in some people of Portuguese ancestry. Oak See also List of Quercus species . An oak is a hardwood tree or shrub in the genus Quercus of the beech family . They have spirally arranged leaves, often with lobed edges, and a nut called an acorn , borne within
442-404: The genus Quercus consisted of Old World and New World clades. The entire genome of Quercus robur (the pedunculate oak) has been sequenced , revealing an array of mutations that may underlie the evolution of longevity and disease resistance in oaks. In addition, hundreds of oak species have been compared (at RAD-seq loci), allowing a detailed phylogeny to be constructed. However,
468-641: The genus are often large and slow-growing; Q. alba can reach an age of 600 years, a diameter of 13 feet (4.0 m) and a height of 145 feet (44 m). The Granit oak in Bulgaria, a Q. robur specimen, has an estimated age of 1637 years, making it the oldest oak in Europe. The Wi'aaSal tree, a live oak in the reservation of the Pechanga Band of Indians , California, is at least 1000 years old, and might be as much as 2000 years old, which would make it
494-545: The hardwood significantly differs from the softwood, and mainly consists of triterpenoids , polyprenols and other higher terpenes. Triterpenoids commonly purified from hardwoods include cycloartenol , betulin and squalene . Hardwood polyterpenes are rubber , gutta percha , gutta-balatá and betulaprenols. Although in small quantities, hardwoods also contain mono- , sesqui- and diterpenes , such as α- and β-pinenes , 3-carene , β-myrcene , limonene , hinokitiol , δ-cadinene , α- and δ-cadinols , borneol . Hardwood
520-1107: The high signal of introgressive hybridization (the transfer of genetic material by repeated backcrossing with hybrid offspring) in the genus has made it difficult to resolve an unambiguous, unitary history of oaks. The phylogeny from Hipp et al. 2019 is: CTB lineage [REDACTED] Cyclobalanoides Glauca [REDACTED] Acuta [REDACTED] Semiserrata East Asian Cerris [REDACTED] West Eurasian Cerris [REDACTED] Early-diverging Ilex [REDACTED] East Asian Ilex [REDACTED] Himalaya-Mediterranean [REDACTED] Himalayan subalpine [REDACTED] Agrifoliae [REDACTED] Palustres [REDACTED] Coccineae (Rubrae) [REDACTED] Phellos (Laurifoliae) [REDACTED] Texas red oaks [REDACTED] Erythromexicana [REDACTED] [REDACTED] [REDACTED] [REDACTED] Dumosae [REDACTED] Prinoids [REDACTED] Albae [REDACTED] Roburoids [REDACTED] Stellatae [REDACTED] Texas white oaks [REDACTED] Leucomexicana [REDACTED] Hardwood Hardwood
546-463: The largest number of oak species, with approximately 160 species in Mexico, of which 109 are endemic, and about 90 in the United States. The second greatest area of oak diversity is China, with approximately 100 species. In the Americas, Quercus is widespread from Vancouver and Nova Scotia in the south of Canada, south to Mexico and across the whole of the eastern United States. It is present in
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#1732765873968572-560: The oldest oak in the US. Among the smallest oaks is Q. acuta , the Japanese evergreen oak. It forms a bush or small tree to a height of some 30 feet (9.1 m). 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 has
598-877: The oldest records in Asia from the Middle Eocene of Japan; both forms have affinities to the Cyclobalanopsis group. Quercus forms part, or rather two parts, of the Quercoideae subfamily of the Fagaceae , the beech family. Modern molecular phylogenetics suggests the following relationships: Fagus (beeches) Trigonobalanus (3 evergreen species) Lithocarpus (stone oaks) Chrysolepis (chinquapins) Quercus pro parte Notholithocarpus (tan oak) Quercus pro parte Castanopsis (also called chinquapins) Castanea (chestnuts) Molecular techniques for phylogenetic analysis show that
624-954: The range in density in hardwoods completely including that of softwoods; some hardwoods ( e.g. , balsa ) are softer than most softwoods, while yew is an example of a hard softwood. The structural polymers of hardwoods are cellulose , hemicellulose , and lignin . The constituents of hardwood lignin differs from those included in softwood. Sinapyl alcohol and coniferyl alcohol are the main monomers of hardwood lignin. Hardwoods contain less amount of non-structural constituents, named extractives , than softwoods. These extractives are usually categorized into three broad groups: aliphatic compounds , terpenes and phenolic compounds . Aliphatic compounds found in hardwoods include fatty acids , fatty alcohols and their esters with glycerol , fatty alcohols (waxes) and sterols (steryl esters), hydrocarbons , such as alkanes , sterols , such as sitosterol , sitostanol and campesterol . The terpene content of
650-550: The supply of some species, such as Burma teak and mahogany , is now becoming scarce due to over-exploitation. Cheaper "hardwood" doors, for instance, now consist of a thin veneer bonded to a core of softwood, plywood or medium-density fibreboard (MDF). Hardwoods may be used in a variety of objects, but are most frequently seen in furniture or musical instruments because of their density which adds to durability, appearance, and performance. Different species of hardwood lend themselves to different end uses or construction processes. This
676-422: The winter, but those of tropical regions may shed their leaves in response to seasonal or sporadic periods of drought. Hardwood from deciduous species, such as oak, normally shows annual growth rings , but these may be absent in some tropical hardwoods . Hardwoods have a more complex structure than softwoods and are often much slower growing as a result. The dominant feature separating "hardwoods" from softwoods
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