Cork oak in the context of "Oak tree"

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 a cup. The genus is widely distributed in the Northern Hemisphere, with 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 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 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.

Suberin is a lipophilic, complex polyester biopolymer found in plants. It is composed of long-chain fatty acids (called suberin acids) and glycerol. Suberin is interconnected with cutin and lignin and forms a protective barrier in the epidermal and peridermal cell walls of higher plants. Suberin and lignin are considered covalently linked to lipids and carbohydrates respectively. Lignin is again covalently linked to suberin, and to a lesser extent to cutin, thus constructing a complex macromolecular matrix. Suberin is a major constituent of cork, and is named after the cork oak, Quercus suber. Its main function is as a barrier to movement of water and solutes.

The Monti Ausoni or Ausoni Mountains constitute a mountain range in southern Lazio, in central Italy. It is part of the Antiappennini, a group running from the Apennines chain to the Tyrrhenian Sea. They are bounded to the north by the Monti Lepini and to the south by the Monti Aurunci. They take the name from the ancient tribe of the Ausoni. The Monti Ausoni consist mainly of friable limestone. Altitudes vary from hills to the 1,152 m of Cima del Nibbio and the 1,141 m of Monte Calvo. Near Pastena are the Grotte di Pastena (caves).

Part of the mountains is protected by a wilderness area, which was established in 1999. It covers 4,230 hectares. Most of the valleys are covered in forests (of oak, cork oak and maple). There are also species of Quercus virginiana, carpinella, aspen and laurel. Beneath the trees are numerous rare and endemic flora, such as Crocus imperati subsp. imperati, Narcissus Poeticus, Asphodeline lutea (asfodelina), Daphne oleoides (spatula daphne) and Iris relicta.

A wine cork is a stopper used to seal a wine bottle. They are typically made from cork (bark of the cork oak), though synthetic materials can be used. Common alternative wine closures include screw caps and glass stoppers. 68 percent of all cork is produced for wine bottle stoppers.

Corks are manufactured for still wines as well as sparkling wines; the latter are bottled under pressure, forcing the corks to take on a mushroom shape. They are fastened with a wire cage known as a muselet.