Cork comes from trees that grow in Mediterranean climates like Spain, Portugal, Algeria, Morocco, Italy, and France. I was lucky enough to visit Portugal this past summer to learn exactly how cork is grown, harvested, processed, and turned into everything from wine bottle corks to hardwood floors. The entire process is incredibly green. Part 1 of this 3-part story shows how cork grows and is harvested from the trees.
Cork trees grow with zero inputs: no pesticides, no irrigation, and no pruning required. In Portugal, which is the number one country for cork production, cork oak trees grow in forests called the Montado. Cork oaks are considered by the government to be a national heritage, and thus oaks are legally protected and regulated. Trees may not be cut down, by law. Trees aren't harvested until about 25 years of age, and then only every 9 years. Not only does this encourage long term, sustainable planning, but it encourages planting crops for future generations, and not for instant profits. Cork oaks grow up to a height of 82 feet and can live for up to 300 years. A cork oak can be harvested many, many times during its lifetime and, on average, will produce 440 lbs of cork—enough raw material to produce approximately 25,000 natural wine corks.
The Montado Cork Oak Forests are actually divided up into many private farms. These aren't tree farms like we're used to seeing, however, as the trees are well spaced and look more like a natural forest. One of the greatest things about the cork oak tree is that it grows without chemical herbicides, fertilizers or irrigation. In fact, cork oak trees require zero inputs besides the sun and natural rain. Once a tree has matured to 25 years old or so, the harvest can then begin.
The harvest or strippings are carried out by hand. It is an extremely delicate operation done by skilled cork harvesters. These workers are well trained and are paid a good living wage. The experienced workers use a machete to slice the bark into sections. They then use a metal wedge to peel these sections from the tree. The bark easily separates from the tree shedding only its outer layer, delineated by a skin-like membrane which separates the bark and the inner trunk of each tree. By law, the tree can only be harvested every nine years, so after a tree is harvested, the last digit of that calendar year is written on the tree to ensure it is not harvested again until the time comes.
Next week, we'll explore how the raw cork material is processed into a usable building material, a process which is powered by up to 90% renewable energy.
Related Link: Why Cork is So Incredibly Green.