Cork oak Quercus suber

A native to the Mediterranean, the cork oak is widely cultivated for its spongy, resilient bark. Impervious to water as well as being fire resistant, it is best known for its use as a stopper in wine bottles.

Cork oak bark has been harvested for thousands of years and with good reason. The Romans discovered that it would float and used it for buoys in fishing nets as well as for making sandals. Being light and impervious to liquid has made cork one the wonders of the natural world, and one that today is a billion pound industry.

Native largely to Mediterranean countries, Quercus suber is cultivated commercially for its cork in France, Spain, Portugal, Italy, Morocco, Tunisia and Algeria. Once the tree is about 25 years old, the thick, spongy grey bark is ready for removal and is cut back with an axe to reveal the red inner bark below. This process does no harm to the tree and can be repeated every ten years for the rest of its life as the tree renews this outer layer of skin.

Portugal is the leading producer of cork in the world, supplying 50% of the world's total and there it is illegal to cut down a tree with the exception of those in forest management where old and unproductive trees are no longer needed.

Uses for cork are varied, from floor panelling to bulletin boards and even in rocket technology, but it is probably most famous as a bottle stopper. For hundreds of years it has been the material of choice for wine bottle stoppers, despite the emergence of man-made alternatives in recent years.