Can you imagine a tree bark that is at the same time successfully used in the production of various types of engines, a baseball balls and champagne? Although this bark is in use for more than a thousand years, today is used even in production of spacecraft parts. However, what is most interesting, wood that is the source of this exceptional material does not have to be cut in order to obtain the useful resources!
What kind of material is it? The Cork - oak (Quercus suber) bark that is inherent to regions of Southwest Europe and Northwest Africa. Cork is in many ways unique material. It is very light, elastic and flame resistant. For the first time cork is peeled from the trunk when the tree is around 25 years old, and consequently every 9-10 years. The first two peelings produce less quality cork. Cork trees live for about 200 years. This extraordinary bark constantly renews and is, year by year, becoming thicker. If you do not peel it, it can reach a thickness of 25 centimeters. Such thick "cloak" protects oak from heat, cold and forest fires. When a wood bark is removed, tree starts to grow a new layer. Bark usually requires about ten years to completely recover.
Throughout the World, there are about 2.2 million hectares of cork oak forests, of which 32.4% are located in Portugal and 22.2% in Spain. Annual production is about 300,000 tons, of which 52.5% originates from Portugal, 29.5% from Spain and 5.5% from Italy.
Cork is preferably made of a hydrophobic ingredient suberina, and due to its water permeability, elasticity, almost complete tightness and fire resistance is used in a wide range of products of which the wine corks are the most common. Cork plugs make up for about 60% of total production in cork industry. Bubble structure and natural fire resistance make cork suitable material for acoustic and thermal insulation in construction industry. Cork furthermore has an anti-allergic properties, it is easy to handle and it represents safe alternative to insulations which are flammable and are emitting highly toxic fumes when burning. Cork granules could be mixed into the concrete as well. Mixture cork granules and cement has a lower thermal conductivity, lower density and good heat retention. Cork is widely used in the footwear industry, fishing and in manufacturing of musical instruments (caps on valves of brass instruments, the batons). Cork sheets, that are often by-products in cork plugs production, are used to create bulletin boards, floor and wall tiles.
Low density of natural cork makes it suitable for making fishing floats and buoys, as well as handle for fishing rods (as an alternative to neoprene). Since the cork remains elastic even when is very warm, it is ideal for making engines seals. Cork is even used to produce heat shield at some spacecraft, which only proves how exceptional cork really is and its purpose diverse.
A well-maintained forest of cork trees are proof that man can wisely and responsibly manage and use natural resources, and not threaten their survival in the process. The centuries-old cork oak trees adorn the landscape, relieve summer heat and provide shelter from the sun.
The crowns of the cork oak tree offer nesting ground for some of the endangered species of birds. Cork oak forests are also a haven for Iberian lynx, which are also threatened with extinction. The next time you open a bottle of wine, look at the cork and remember how versatile and useful material cork really is. This natural, biodegradable material is obtained from the bark which renews itself.
The cork oak forests offer refuge to some endangered species. Should we not then appreciate this beautiful and precious wood?