How is Cork Harvested – (With Videos & Illustrations)
Cork is a precious versatile tissue obtained from the outer bark of the cork oak tree (Quercus Suber). It has a unique structure that resembles the structure of a honeycomb with every half an inch containing air spaces filled with air.
Unlike other oak trees, the cork tree is evergreen, grows up to 2500 inches tall and lives for 200 years. Corks are harvested once every nine years meaning that generations of families can harvest the same tree over decades. The first stripping harvest produces virgin cork, which is hard and used in making flooring and insulating materials. Only the third and subsequent harvests produce quality corks to be used as bottle stoppers.
Cork harvesting is an old skill that only experienced descortiçadores handle in six stages. The practice commenced in ancient Greece three hundred years ago. Today, corks harvesting is still done in teams using hand axes with no viable mechanization and each generation tutoring the next in a continuous process.
Stage 1: Opening
Once a cork tree is mature, a vertical cut is made using an axe choosing the deepest cut on the cork bark. The edge of the axe is used to separate the inner and outer cork and determine the level of difficulty during extraction.
Stage 2: Separation
The edge of the axe is inserted between the strip and the inner bark allowing the plank to separate from the tree.
Stage 3: Dividing
A horizontal cut is then made defining the size of the cork planks to be removed and what is to remain on the tree. The thickness of the cork is determined by the sound resonating from the axe.
Stage 4: Extraction
The plank is removed from the tree by a pair of experienced descortiçadores so that it does not split. The process is repeated until the entire trunk has been stripped. The larger the plank the higher its commercial value.
Stage 5: Removing
Having stripped the planks, the fragments of the cork attached to the base of the trunk are slowly removed with the axe edges. The spongy corks peel like oranges, with crackling tearing sounds leaving a pale living layer of the bark.
Stage 6: Marking
The final stage of harvesting corks is marking the trees with the last number of the year of harvest. The harvested corks are then stacked in piles in the forests or factory yards allowing them to stabilize.
Corks harvesting takes place during late spring and summer when the cells are fragile and easy to tear without damage. In ancient Greece, the harvest period commenced on the first day of the full moon. The tree forms new layers of cork and restores the protective layer. Since no trees are cut down, harvesting corks are considered the most sustainable activity providing a balance between man and nature.