The cork oak is a medium-sized tree typical of Mediterranean forests and native to Europe and North Africa. It is commonly known for the cork it produces, which has multiple uses, the most widespread being for bottle stoppers for alcoholic beverages. We have all vigorously uncorked a bottle of champagne at some celebration, and we owe this to this robust and long-lived tree, capable of living for over 100 or 200 years.
If you want to know what a cork oak is and learn more about this prized tree, we invite you on a journey through the world of botany with our protagonist, the cork oak.
What is a cork oak? ecology and distribution
The cork oak (Quercus suber) is a medium-sized, evergreen tree native to Mediterranean forests, originating in Europe and North Africa . It has spread extensively to other regions of the world through human activity for the harvesting of its bark, from which the highly prized cork is extracted. It is a very long-lived tree, typically living between 150 and 250 years, although some cork oaks have been recorded as being over 500 years old, such as the "Bosco di San Pietro" in Caltagirone, Sicily (Italy ).
Its scientific name, Quercus suber , derives from the Latin word quercus , which the Romans used to designate the common oak ( Quercus robur ). The specific epithet, suber, in Latin means cork or cap, and that is why the cork oak is also known as the cork oak and in some regions as the chaparro or cork oak , especially when referring to younger specimens.
It has a thick and rough bark that becomes quite thick over time, especially if it has received heavy rainfall, since the cork oak is a tree that requires a large supply of water. Its bark is harvested between 9 and 14 years of age and the quality of the cork it offers is proportional to the number of years it takes to generate. The optimum thickness for the collection has been set at 24mm, which is the diameter of a standard plug, its main application. To obtain that effective thickness, it will be necessary to collect rinds that are about 30mm thick, which, after processing, will result in the desired measurement.
Cork oak trees are widely cultivated in Spain, Portugal, Algeria, Morocco, France, Italy, and Tunisia, covering an area of 2,5 million hectares. Portugal accounts for 50% of global cork production , and therefore, its felling is prohibited in this country, except for certain forest management practices or the removal of old, unproductive trees.
Habitat and ecology
As we mentioned at the beginning, the cork oak is a typical tree of the Mediterranean forest and coexists with other representatives of this type of ecosystem, such as the holm oak. Unlike its counterpart, the cork oak needs more moisture and tolerates cold climates less well, and even less so lime. This is why, when these three requirements are not met, and as the climate becomes more continental, it is replaced by the holm oak, which is more resistant to temperature increases.
The acorn of the cork oak occurs in the months of September to January, when frost and rainfall are much more frequent, essential needs for its development.
Distribution of the cork oak
In Spain, the cork oak is found primarily in the western Mediterranean region.
In Andalusia we find the largest specimen of the Iberian Peninsula and it is located in the natural park of Los Alcornocales in Cádiz. Likewise, the cork oak forests of Extremadura, Catalonia and Espadán stand out, and in Castilla y León the densest surfaces are those of Salamanca, Ávila, and Zamora.
More dispersed in distribution, we find cork oaks on the Galician coast and in Orense, as well as in the valleys of the Sil and Miño, to which are added the relicts of Bierzo, Arribes del Duero, Burgos and Valladolid.
The cork oak: a tree of precious economic value
The cork oak provides very useful resources that move huge amounts of money around the world. It has become popular for its cork but it is not the only resource it supplies, its fruit - acorns - and its wood are also used.
The European cork industry produces 340.000 tons of cork annually, valued at €250 million, representing an average of €0,70 per kilogram of cork. It employs 30.000 people, and wine closures account for 15% of cork use by weight and 80% of the business.
Cork
It is believed that the cork of the cork oak is the result of years of evolution that arises as protection against fire , given the frequent fires that occur in Mediterranean forests during the summer months.
Cork extraction is a highly specialized task and is carried out every 9-14 years, depending on the production and destination of the cork.
The first cork harvest from a tree occurs between 30 and 40 years of age. This initial harvest yields a lower-quality cork known as "bornizo." This is because this first layer has endured the tree's growth and its progressive thickening from the initial shoot to the mature trunk, resulting in deep cracks in its outer bark and irregular cork slabs—the "bornizo." This is the cork used to decorate nativity scenes , simulating rocks or mountains . Once the "bornizo" is harvested, subsequent layers have a more regular appearance, as the relative increase in the tree's circumference is much smaller.
Cork has many uses, but its main one is undoubtedly the production of stoppers for bottles of alcoholic beverages , such as wines, spirits, sparkling wines, or champagne. After manufacturing, these stoppers undergo a rigorous quality control process.
Once the loads suitable for use have been selected, the defective ones and the remaining cork material are sent to a recycling center where they are shredded and formed into cork agglomerate. The cork agglomerate is used for lining satellite capsules , for flooring and wall coverings , or for manufacturing shoe and clothing insoles.
Due to its properties—such as fire resistance, partial moisture absorption, and thermal insulation—cork agglomerate has many applications, making it so suitable for the aforementioned uses.
Wood
Cork oak wood has traditionally been used to make charcoal, although it is not as effective as that obtained from holm oak.
Acorns
The fruit of the cork oak is the acorn , also known as acorn or lande . They are bitter, so they are not used for human consumption. But they do have a use: fattening animals , especially Iberian pigs, whose exquisite meat is due to their diet of cork oak acorns, among other factors.
In general, acorns are used to feed a wide variety of animals, from pigs to birds, such as cranes in winter due to their high caloric intake.