Cork Material

Why is cork material so amazing?

What is cork wood?

Cork as we know it come from the actual Bark of the Cork oak tree (Quercus suber), not the actual wood.

Its Structure is amazing and one of a kind!

Cork presents a characteristic cellular structure in which the cells have usually are pentagonal or hexagonal shape. The cells of cork are filled with a gas mixture similar to the air, making them behave as authentic “pads,” which contributes to the capability of cork recover after compressed.

The material is composed of suberin (45 wt %), lignin (22 wt %), polysaccharides (18 wt %) and extractable compounds, such as lipids, terpenoids and phenolic compounds (15 wt %) and the rest is Air.

Where does the Cork tree grow?

There are about 2,200,000 hectares of cork forest worldwide; 34% in Portugal and 27% in Spain. Annual production is about 300,000 tons; 49.6% from Portugal, 30.5% from Spain, 5.8% from Morocco, 4.9% from Algeria, 3.5% from Tunisia, 3.1% from Italy, and 2.6% from France. Once the trees are about 25 years old the cork is traditionally stripped from the trunks every nine years, with the first two harvests generally producing lower quality cork. The trees live for about 300 years.

Since when do humans use cork material?

In 3000 BC, cork was already being used in fishing tackle in China, Egypt, Babylon and Persia. In Italy remains dating from the 4th century BC have been found that include artifacts such as floats, stoppers for casks, women’s footwear and roofing materials. Also dating from that period is one of the first references to the cork oak, by the Greek philosopher Theophrastus who, in his botanical treatises, referred in wonder to “the ability that this tree has to renew its bark after it has been removed”.

 In Pompeii, the Roman city destroyed by the brutal eruption of Mount Vesuvius, wine amphorae sealed with cork have also been found.

In the 19th century, France, Italy and Tunisia invested in the systematic planting of cork forests and countries as different as Russia or the United States also started planting cork oaks.

Harvesting the Cork from the tree.

The harvesting of the bark is only made by hand, there are no machines who are able to gently remove the bark without hurting the tree. If the tree gets hurt, insects and termites are able to attack the tree easily.

The harvesting is done every 9 years, this way the tree has time to regenerate and give us a new layer.

If the tree is not being harvested, it will only survive 25-30 years, but being harvested and used, they live more then 300 years (there are 500 years old ones).

A special ax with special knowledge is used, one side to cut through the layer making an incision, and the other side is to peel it off from the tree. The extractors learn this from their fathers and grandfather, its a work that take a lot of years to learn the skills on cutting off the bark.

The cutting usually takes place in June or July so that the cork will have a chance to dry out before being processed. 

Protecting cork tree
After a lot of research i could only find this source that said when the law was passed to protect cork tree. In 1097 a law was passed, for protection of species, Wild flora, Endangered species, Desertification.

As there was a decline in Portuguese production of cork, because apparently the cork stopper gave a taste to the wine, the wine industry started using plastic and aluminum stoppers.

The Portuguese farmers started farming eucalyptus, which was bringing them more money in less time. This was a big mistake in the wild fires, because cork trees are more resistant to fires the eucalyptus, also the eucalyptus need more ground water then the cork oak tree.

Also by not cutting out the bark after 9 years, the cork tree slowly dies.

Examples where cork is used

Cork material is one of a kind as it is Impermeable (Waterproof), Fire retardant, Insulating, Flexible, super light and antiseptic. This way the material can be used for countless products.

Most common is the Wine Bottles Stoppers but there are countless things like : Instruments, Sports, Hats, bags, clothing, jewelry, shoes, furniture, lamps, floors, pin walls, coasters, sinks, cars, walls and even in Space Crafts……

Mind blowing!!!!!

 

Some sources:

https://www.nature.com/articles/s41598-019-55193-9

https://en.wikipedia.org/wiki/Cork_(material)

https://corkforest.org/history-of-cork/

https://www.ecolex.org/details/legislation/decree-law-no-1692001-protecting-cork-oak-and-holm-oak-forests-lex-faoc026584/