The life cycle of cork as a raw material begins with the peeling of the bark of cork oak, a process also known as harvesting. After the bark is stripped, the cork enters the processing process for the production of a wide variety of products, including cork stoppers, building materials and design products.
Cork is usually harvested by skilled workers during mid-May or early June to mid-August or at the end of August, when cork oak is in the most active growth phase.
According to Portuguese law, cork oak must be harvested for the first time when the tree is 25 years old and the tree circumference is 1.3 meters away from the ground. Since then, cork oak can be peeled off every nine years for an average of 150 years.
The first harvest was called “desbóia”, and the peeling cork structure was very irregular and the texture was too hard and difficult to handle. This is called “primary picking cork”. The quality of “primary cork” is a far cry from the quality necessary to make cork stoppers, so it can only be used to produce products other than cork, such as flooring and insulation.
The cork obtained in the second harvest has a regular structure and reduced hardness, but is still not suitable for the production of cork, which is called “recovered softwood”.
From the third harvest, cork reached the high quality required for the production of cork, its structure is regular and its performance is stable. This is called “amadia”.
The harvesting of cork oak is an ancient process, and the whole process can only be done by experienced workers. Workers need to be skilled enough to avoid damaging trees. They will choose the deepest crack on the bark and cut it vertically with an axe, while rotating the axe and rotating the edge of the ax to separate the inner and outer layers of the bark. The bark level is then carefully cut to prevent breakage. Finally, the worker will mark the last number of the year of the year on the trunk. Because the growth direction of the cork oak bark is from the inside to the outside, the number written will not be covered to facilitate the identification of the next peeling.
