Origin : the Holm oak, Q. ilex, and the Cork oak, Quercus suber, are Mediterranean species, although it is possible to meet the holm oak more in the North, but not the cork oak. Habitat: they are next to English oak and to maritime pine as part of an irregular grove or of a coppice (more details look at table below). Hardiness: zone 8 (it supports cold until -12 °C or 10 °F). Lifespan: see table below. Height: 20 m. Form (insulated tree): as other oaks, they have an irregular and broad crown (holm oak to the left). Branches are powerful and tortuous. Bark: thick, especially to the cork oak (photo to the left). The thick and insulating bark of the cork oak burns only superficially and protects conducting tissues of the sap along with the generator sitting cork. After a fire, bud "sleeping" under the bark wake up and give birth to new shoots, which allows the cork oak tree, about twenty months after the passage of fire, to re-form a plant crown. However deprived of its protective bark, the cork oak is unable to defend itself against the fire. It was so possible to establish that the mortality in the event of a fire attained 100 % immediately after the harvesting of cork, 70 % after three years and only 2 % for after nine years. Leaves are persistent (during 2 or 3 years) and alternate. The blade, carried by a short petiole, is tough, in oval lengthened form ("obovate"). The margin is lobbed or deeply toothed. The top is dark green, glazed so as to prevent evaporation in summer. The flower is unisexual: males are grouped in flexible catkins with long peduncle, females in upright spikes.
Its fruit is an acorn protected half by a cupule formed by long, grey and downy scales. It falls for itself (leaving its cupule) when it is ripe, in September-October. Use: the cork is used for stoppers of very good quality. 12 harvests on the life of a tree are performed. The wood of the cork oak is very dense, very hard and difficult to work and therefore little used.
The kermes oak, Quercus coccifera, also of Mediterranean origin, is a shrub (5 m), often bushy, with numerous branches pubescent on the plant made by young brown stellate hairs. The bark is gray, smooth and slightly cracked. The leaves are evergreen, leathery, simple, alternate and short-stalked, and they have an oblong shape, rounded at the base, pointed at the top, and a spiny toothed edge. The upper surface is dark green, the inner, lighter is marked with prominent veins. The flowers are unisexual: male flowers are catkins short, flexible and pendants, females are isolated or connected by two in the axils of leaves. The fruit is an achene 3 cm oval, protected by half a cup with rigid scales. This oak likes limestone soils and stony scrubland type associations. You can find an insect on its branches, Kermococcus vermilio, cochineal which causes galls (growths) used as red dye.
Holm oak Q. ilex
Cork oak Q. suber
heat, drought, rocks; it supports cold.
Demand heat and light. Prefers siliceous soils and humidity. Fears frost, limestone and rocky substrates.
persistent, toothed, tough short petiole, hirsute dark grey underside
persistent, simple, alternate, coriaceous, ovate - lanceolate, provided with 4 7-teeth pointed or sometimes entire; the petiole is longer than in the holm oak; the top is of a less dark green than in the holm oak