Quercus suber L.
Eng.: Cork oak. Spa.: Alcornoque. Fre.: Chêne liège. Ara.: Ballut, fersi, frchi, chuber, fernan, fernène, bellut fellini, fellin, dlam. Tam.: Ahlidj en iderren, igigui, agut, harnech, afersi, aferki, iferki, (cork): akartassu.
Evergreen tree, monoecious, up to 20(25) m in height, ovoid-rounded in overall appearance. Trunk straight or somewhat tortuous in rocky terrain. Bark suberose, very thick (up to 25 cm), with deep longitudinal fissures, by which this tree is easily differentiated from Q. rotundifolia. This bark or cork is harnessed by humans, extracting it every 8-12 years, then leaving the tree with a distinctive appearance, with branches covered by thick bark and bare and reddish trunks, which then become blackish-brown to greyish as the tree grows the new bark. Branches tortuous, upright or extended. Branchlets whitish-tomentose. Leaves [2.5-7(10) × 1.2-4.5(6.5) cm], alternate, perennial, ovate to ovate-lanceolate or oblong, coriaceous, usually with few barely noticeable teeth, sometimes entire, dark green and bright on the upper side and whitish-tomentose on the underside, with tomentose petiole 6-20 mm. Male flowers in yellow and pendant catkin 4-8 cm, very numerous. Female flowers solitary or grouped in 2-5 on the axil of a linear bract. Fruit (the acorn) ovoid (20-45 × 10-18 mm), with chestnut-blackish nut and cupule with short lower scales, ovate-triangular, imbricate and ± applied, and upper scales longer, with recurved, not applied tip.
Flowering:
March to May, sometimes until the autumn.
Fruiting:
September to January. Acorns from autumn flowering ripen in the summer.
Habitat:
Siliceous terrains, on diverse soils, but generally devoid of lime, which it cannot tolerates. From almost sea level to mid mountain. In semiarid to humid bioclimate, on thermomediterranean to supramediterranean floors.
Distribution:
Western Mediterranean region. In North Africa it can form large pure or mixed forests. Common in NW Tunisia, all of the Algerian Tellian Atlas and in central and northern Morocco, reaching in the S to the western High Atlas, with single stands and isolated woods.
Observations:
The most curious aspect of this species is its bark or “cork”, which has diverse uses (plugs, insulation, building materials, decoration, textiles and footwear, etc.), constituting a considerable source of income for producing countries. The world largest production takes place in the Iberian Peninsula, followed in order of importance by NW Africa, where there are almost 1 million ha of cork forests (pure and mixed), of which 480,000 ha are in Algeria, 400,000 ha in Morocco and 99,000 ha in Tunisia. The world’s largest cork oak forest, the Mamora (Morocco), with some 60,000 ha, is seriously threatened (pests, overgrazing, various infrastructure, eucalyptus plantations, etc.)
The Q. suber forest is sparse, which favours the growth of grasses in good quantity and quality, very exploited since ancient times, like acorns. Also, firewood and wood to burn and make charcoal have been exploited since ancient times. However, its best renewable resource is the cork. Cork extraction does not harm the tree if it is done with care; however this is usually not the case, and frequent infliction of small wounds allow small insects to penetrate, which can cause a number of diseases that can kill the tree. Even in the best cases, the trees from which cork has been extracted live far fewer years than those with an intact bark. Between the wood and the bark there is a thin layer that protects the trunk after the cork has been extracted and until a new bark is formed. This thin, yellowish layer is rich in tannins and has been widely used for dyeing by tanners. Extracting this layer results in the death of tree in 1-2 years.
The forests of this species, as well as those of Q. rotundifolia and other less widespread Quercus species, have an extraordinary value as creators and protectors of soil, water regulators and favour great biodiversity.
Conservation status:
A common and widely distributed species, not considered threatened. Currently, it has not been assessed at a global level in the IUCN Red List of Threatened Species.