Properties of cork
In Portugal, which is located in the south western part of the continent of Europe, a huge area of around 720,000 hectares is covered by the cork oak trees and the bark of the cork oak tree is known as cork which is harvested for a total of about 9 years. The Mediterranean type climate of Portugal is extremely conducive to cork oak cultivation and the country accounts fro about 50% of total cork production in the world and the versatility of cork which is a vegetable tissue makes it valuable for a variety of uses as cork stoppers, in fishing rods and floats, in buildings as floor tiles, for artistic purposes, in pharmaceutical plants, in military and automobile industries etc. It is interesting to note here that cork harvesting is also a natural process and no artificial applications are initiated in order to enhance the quality or quantity of the cork. Therefore all the properties of cork are indigenous to it and are by no means made more productive through synthetic means.
Cork is the bark of the cork oak tree and this bark attains enormous thickness and is extracted after about 25 years from the cork oak tree to be harvested fro another period of over a decade. The cork so obtained is flexible, light and compressible and is resistant to gases and liquids. It is not only fire-resistant but also at the same time acts as an outstanding acoustic and thermal insulator. It is also highly resistant to abrasion. All these characteristics are immensely influenced as a result of its chemical properties comprising of mainly suberin (45%), which can be echoed in the scientific name of the cork oak tree, Quercus suber L. It is this suberin which does not allow the passage of gases and liquids within the cork cells because of the presence of organic acids in suberin and thus makes it compressible and elastic as well.