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Cork oak - cork application and use
Sustainable consumption usually means choosing the lesser evil, using materials whose production harms nature as little as possible. However, demand for some products protects unique biotopes with an immense biodiversity. These include natural cork, which is obtained from the bark of the cork oak of the Iberian Peninsula and North Africa.
contents
- A special bark
- Adaptation to the Mediterranean climate
- A biodiversity hotspot
- A cultural landscape
- Water storage and soil fertilizer
- Bioschinken
- Vulture and eagle
- An extraordinary substance
- Flowering, decline and upswing
- Germany behind
- What speaks for cork?
A special bark
The cork oak is the only tree whose bark peels off without the plant dying. Even more: regular peeling makes the oak resistant to fire, produces a thicker cork layer and binds about 5 times more CO2 than "normal" trees. Altogether, the cork oak forests of the Mediterranean produce 14 million tonnes of CO2 per year in cork.
Cork - the best known use of natural wood is the "cork" for closing sparkling wine and wine bottles. Picture: karepa-fotolia Adaptation to the Mediterranean climate
The cork oak has adapted to the dry summer on the Mediterranean. It closes the stomata on the underside of the leaves so far that it barely loses water, but at the same time the tree does not dry out; Its roots reach several meters deep and from there more than 70% of the water in summer.
Cork is an elastic fabric that firstly does not let water through and secondly it strongly isolates it. These are dead cells with a substance called suberin. These also produce other trees, but only the cork oak can form from these bark. Every year, she creates new cork rings via mother cells.
It insulates warmth well. What makes the bark attractive to humans has probably helped the tree to survive in evolution and is an adaptation to the forest fires that are part of the natural events on the Mediterranean.
For example, only the seeds survive in the Maritime Pine, and only the saplings of the holm oak forest fires; in the case of the cork oak, all the branches that the cork protects. It is no coincidence that cork oaks are the dominant species in the forests named after them.
A biodiversity hotspot
In cork oak forests of Andalusia and Portugal there is an adapted fauna and flora, which loses its habitat without the traditional use of the bark. In fact, the Spanish cork oak forests have been largely cleared to give way to "lucrative" eucalyptus plantations that are poisonous to the endemic flora and fauna.
The cork oak forests of the Sierra Morena north of Seville, for example, house the largest population of the Spanish lynx, also known as the Pardell lynx, because its narrow spots are reminiscent of a leopard. The Iberian relative of the Eurasian lynx weighs only one third of the local cousin, concentrates as prey on rabbits and is much more dependent on the cohesive forests than the Eurasian lynx.
It is the rarest cat species in the world, in 2017 the stock was between 215 and 265 specimens, which are mainly concentrated on two protected areas in Andalusia: the National Park Coto de Donana and the Sierra de Andújar in the province of Jaén.
A cultural landscape
The province of Jaén is by no means an "original" wilderness, but a cultural landscape that has been used for centuries. The locals traditionally live on the cork oaks. A tree delivers up to 200 kilograms of bark in its lifetime. To harvest them, the users do not kill the oak, but peel the bark off the living tree, which does little harm to it. The acorns serve the traditional pig.
The pastures named in Spain Dehesa were created since antiquity, because the shepherds drove their pigs, cattle, goats and sheep into the previously dense forest. Cattle and sheep ate the grass, the pigs the acorns. The jungle became a park-like landscape that depends directly on the cattle drive.
It is a sensitive system. In the modern age, the farmers fed the animals additionally with cattle feed, and the intensive animal mast ensured that the mass of animals ate the renewable trees. That's why many existing cork oak forests are outdated. Many other farmers completely abandoned the pasture, causing the park-like cork oaks to fade. The result is forest fires that afflict the Spanish peninsula almost every year.
Water storage and soil fertilizer
Cork plantations have an important role in the water balance and influence enormously as the water penetrates the surface and flows away, the trees retain water. They prevent erosion and save rain. The treetops catch more water than the plants on the ground, and the water flows down the trunk to the ground, which makes the soil more receptive.
Cork oaks provide the soil with nutrient-rich material, which on the Mediterranean is of crucial importance for the fruit bouquet of the earth.
Bioschinken
As in the past also in this country, the pig farmers operate woodland pasture. The black or red-brown animals live, mostly fenced off in a large area, under the cork oaks, which at the same time give them the necessary shade in the heat of summer in southern Spain and supply them with plenty of acorns for food.
Cerdo Iberico has already been proven to breed Roman legionnaires. It is smaller and faster than the modern high-performance breeds and delivers the Jamón Ibérico terminado en montanera. Gourmets love this ham, as the acorns of the stone and cork oaks provide a taste reminiscent of walnut. At the Rebeco Jamón iberico, pigs are fed pigs with acorns, but at the end they are fed with grain and conventional cattle feed.
Popular Iberico pigs in the breed. Picture: daviles-fotolia The pigs live close to nature in a species that almost matches that of wild boar. In fact, the black to reddish-brown color probably stems from the fact that wild boars keep covering the free-grazing domestic pigs.
The woodland pasture ensures that little undergrowth forms at the bottom of the forests, and thus creates an open area, which in turn provides habitat for various reptiles, birds and mammals.
Vulture and eagle
The cork oak forests of the mountains north of Seville not only provide a habitat for the Spanish lynx, but also for a variety of black birds that are unrivaled in Europe. Above all, these are the extremely rare Spanish imperial eagle and black vulture.
Golden eagle and griffon vulture breed in the higher elevations of the mountains, preferring cliffs to create their clumps. Imperial eagles and black vultures, however, rely on cork oaks as breeding trees. The very rare in Europe monk vulture has its main spread on the continent in the Spanish cork oak forests. In the Sierra Morena, conservationists cut off the ecologically harmful eucalyptus trees and planted cork oaks in their place to create a habitat for the black vultures. The now-common Bonelli's Eagles live mainly on wooded mountain slopes and have in the Sierra Morena an ideal habitat, as well as the Zwergadler and Schlangenadler.
In the cork oak forests of Spain hibernate up to 50,000 cranes, and more than half of all plants of the Mediterranean area are only found here. Further fauna of the cork oak forests include wild cat, genet, boar, red deer, bee eater, blue lemur, common raven, hawk and Honey Buzzard, migrant and tree hawk, black and white stork, Jade Cuckoo, eagle owl and gliding, wryneck, lesser spotted woodpecker, red-necked goatfish, Spanish yellow wagtail , Stonechat, Orpheus, Blasphemus, Orpheus Warbler, Spectacled, Provence and Whitetail Warbler, Mountain Warbler, Red-headed Shrike, Redstart, Fenstitch and Ortolan, Red-legged Partridge.
As in this country in the orchards, the cork oaks are a paradise for birds that need open areas with mature trees. These include hoopoes such as Little Owl and Scops Owls, who raise their cubs in the caves of ancient cork oaks. This also includes the blackmail that disappeared from Germany when these open landscapes disappeared with trees like the snake eagle, which breeds on low trees and seeks its food, lizards like snakes, on sunny hills.
An extraordinary substance
Cork oaks are resistant to fire such as heat, cold as injuries. They owe this to their bark and their cork layer. The cork protects the trees from drying out in the hot summers, it withstands infections and even forest fires. In house walls, cork keeps heat and cold, as a shoe sole he bounces off the steps. In wine bottles, it serves not only as a closure, but ensures that the wine can breathe.
Cork floats on the water, is perfect for the insulation of flats, keeps heat as well as cold and sound and lasts almost forever.
About a quarter of the harvest today serves as a bottle cork. The rest is ground and glued with binders. The result is pressed cork, cork flooring, shoe soles, pin boards or insulating cork.
Unprocessed pieces of cork bark are popular with pet owners, especially for rodents and terrariums, for many reasons: First, the bark peeled from the tree has a round or semicircular shape, which lizards, frogs, snakes, hamsters, rats or mice use as shelter.
Secondly, cork does not mold, a blessing for anyone who holds rainforest dwellers like tree frogs that need just the high humidity molds love.
Third, cork, which is both elastic and resistant, provides excellent protection against the teeth of rodents and the claws of lizards, as well as providing a resilient surface that protects the animals' feet.
Flowering, decline and upswing
Plastic corks or screw caps often replace the cork from the oak bark. The demand for "real" corks is the best way to protect the habitat of cork oak forests and thus one of the most valuable biotopes in Europe.
In the 18th century, corking began in mass production. Around 1900, it reached its peak, because reefers cork contained as insulation. But in the 1960s, the cork industry collapsed - the cause was the then new plastics, which were not only cheap, but also considered modern.
The decline in prices due to lack of demand led to a false reaction of the producers: they harvested more cork to earn the same revenue as before. This over harvest damaged the trees.
In addition, the cities in southern Spain and Portugal expanded more and more - where used to be old cork forests, today concrete castles extend. Other cork oaks gave way to monocultures for tomatoes or flowers. Meanwhile, the largest cork killer became the eucalyptus plantations.
Eukayptus mainly uses the wood and paper industry. The trees are growing fast. Ecologically, they are a disaster. They drain the water from other trees, and their oil causes them to go up in flames in a forest fire.
Today, however, the cork industry has recovered a bit: cork granules are selling well, so even the "waste" of bottle corks finds a market and is popular as a health-friendly binder. Cork recycling slows down the danger of over-exploiting the oak stands.
Germany behind
In Germany today, 70% of all wine bottles are sealed with aluminum, a material that harms the environment and releases almost 25 times more CO2 than cork bark cork.
What speaks for cork?
Cork is a natural product. Attracting it does not harm the ecosystem but ensures it is preserved. When cork bark is carefully degraded, it represents a sustainable product in the best sense of the word. (Dr. Utz Anhalt)