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Quercus suber
Cork oak
Cork oak (Eng); alcornoque, corcho, chaparro (Spa); surera (Cat); artelatz (Baq); sobreiro (Glg); sobreiro (Por).
Non-Native
DID YOU KNOW...? The shepherds and farmers on the Canary Islands treated animal diarrhoea with infusions made of green cork oak branches.
DESCRIPTION
The cork oak is a large tree that can be as much as 25 m tall, has a wide, rounded crown and looks a lot like the holm oak (Quercus ilex). Nevertheless, it can be differentiated by its bark, the cork, which is very thick (sometimes more than 15 cm), rough, light and, which when removed, reveals a reddish trunk that darkens slowly. The leaves are simple, persistent, alternate, ovate or rounded, with a dark green upper side and a whitish underside. The margin is entire or has soft points that are not prickly like those of the holm oak. The twigs are covered by a whitish or rusty-coloured felt (flock) and in spring the male and female flowers are borne on the same tree. The yellowish male blooms appear on hanging peduncles (catkins), whereas the tiny female flowers are in ones or twos. The acorns tend to be bitter and have a husk, or cupule, with soft, protruding scales.
ECOLOGY
The cork oak is a typically Mediterranean tree that grows best in places with a mild climate. It is always found in acidic or lime-free soils, and prefers loose, deep, well-drained substrates. It needs somewhat more moisture than the holm oak and does not withstand frosts as well. In the Canaries, the cork oak has principally been cultivated on the humid midslopes, or medianías (zones between altitudes of 600 and 1500 m), from where it is has become established in the wild forming stable populations that reproduce through both root shoots and the germination of acorns. Sometimes, this expansion has been aided by farmers, who have used it as cattle fodder. In addition, it is known that in the not too distant past, occasional plantations of this species were set up onthe windward slopes of Tenerife, located in the monteverde forest domain. The acidity of the soil in the native heathland seems to have favoured the presence of this species.
DISTRIBUTION
This tree lives in the western Mediterranean region. In the Canary Islands it was introduced when the islands were first colonised and is more abundant than the holm oak (Quercus ilex). It is only considered to have become established in the wild in Tenerife and Gran Canaria.
