Cork

Cork is a raw material that comes from the bark of the cork oak tree. They are slow-growing trees that thrive in very sunny areas with moderate to dry climates and some humidity, like in countries along the Mediterranean Sea to northwestern Africa. They can be found in countries like Portugal, Spain, Italy, Morocco, Algeria and Tunisia.

The Cork tree has a lifespan of 150 to 250 years and are unique from other tree species specifically for their ability to regenerate new bark, therefore classifying them as a renewable and sustainable resource.

Cork oak tree forests supports diverse ecosystems. It prevents soil erosion from rain, by aiding in the increased absorption of water. It acts as a barrier to the encroachment of desertification from North Africa. It also helps mitigate climate change by absorbing 10 million tons of carbon dioxide from the atmosphere every year.

Harvesting cork trees does not kill or harm the trees or the environment. The harvesting of cork entails stripping off the outer bark from a tree that is kept alive and intact. Stripped trees are actually more effective in fighting climate change than unharvested trees because it absorbs and stores 5 times more carbon dioxide in order for it to regenerate new bark.

Portugal is the main producer of cork, contributing to about half of the world’s output of commercial cork. The importance of the cork industry to the Portuguese economy has brought about strict regulations to protect this highly valued resource from mismanagement and depletion.

The regulations protect its proper growth and enforce strict restrictions on harvesting. A cork tree must be at least 25 years of age before it can be harvested for the first time. This “first” cork harvest is called virgin cork. Virgin cork is the finest quality and the most valuable type of cork due to its smooth appearance, uniform color, with minimal blemishes and imperfections. These are made into premium wine stoppers, high quality flooring, wall coverings, luxury fashion and quality design products.

Harvest season occurs between Mid May to August. The tree is kept intact and only the bark is masterfully harvested by a highly skilled worker called an “extractor” or “stripper”, by using only an axe with a slightly curved blade, the extractor carefully strips just enough layer of bark without harming the interior tissue of the tree. This detail of preserving the interior layer is very important as it allows the tree to regenerate new bark to produce more cork. Portuguese laws prohibits harvesting more than once every 9 years. The tree needs 9 to 12 years in between harvests to regrow bark thick enough to be useable cork. A tree yields an average of 13 harvests in its lifetime.

The harvested cork barks are stacked and pressed under concrete slabs and kept outside to weather for 6 months. Then the cork planks go through a boiling process to clean and soften them. Boiling causes the cork to expand slightly. After boiling, they are inspected and cut into smaller pieces. Any defects are also cut from the cork during this stage.

The planks are visually sorted by quality. High quality and “punchable” pieces are bundled and sent to the North of Portugal to be made into wine stoppers for export to Europe and the rest are sent to the south to be made into other less premium applications. Every bit of cork is utilized, nothing goes waste. Residual cork pieces are recycled, ground up and compressed and made into lower grade stoppers, bulletin boards and insulation to name a few.

Some products made with cork…

wine and olive oil stoppers, cores of cricket balls, shoe soles, shoes, table mats, bath mats, bags, hats, cigarette tips, home and fashion accessories, cork wool (for cushions and mattresses), granulated cork for insulation in ship building, packaging for fruits and eggs.

The cork industry is supported by environmental groups such as the World Wildlife Fund, the Rain Forest Alliance, and the Forest Stewardship Council.

With the help of reforestation programs funded by the European Union and the Portuguese Government, the cork forest area under cultivation in Portugal is growing by about four per cent per year. New trees are being planted at twice the rate at which old trees are dying.

Contrary to a common misconception, it is estimated there is currently sufficient harvestable cork in Portugal's cork forests to meet market demand for more than 100 years.