The Cork Harvesting Process

Cork is the name given to the protective bark of the cork oak tree. The cork oak is the only plant species capable of producing high-quality cork. This raw material gave rise to an industry that is unique in the world and vital to the survival of the Montado and the Portuguese economy—since cork accounts for 2% of the country’s exports.

Cork harvesting takes place in the Montado, in the Alentejo. The Montado, a forest of cork oaks, accounts for 23% of Portugal’s forest cover. The Montado is also one of the 35 global biodiversity hotspots, home to more than 160 species of birds, 24 species of reptiles and amphibians, and 37 species of mammals, including the Iberian lynx. The Montado absorbs 14 million metric tons of CO₂ every year, thereby preventing it from being released into the atmosphere.

The cork oak lives, on average, 200 years. Only after the first 25 years of this long and fruitful life does cork begin to form on the trunk of the cork oak. The first harvest, called “bornizo,” yields cork with an irregular structure that is extremely hard, making it difficult to work with. This “virgin cork” is typically used for flooring and insulation, as it is not flexible enough to be made into corks.

Only after the third year of harvesting does the cork possess the properties suitable for the production of corks. After each harvest, the cork oak takes nine glorious years to regenerate and provide us, once again, with its cork. Over its lifetime, the cork oak will yield, on average, 15 harvests of cork. 

Throughout this process, it is absolutely crucial that all necessary precautions be taken to avoid damaging the trees. If a cork oak is damaged, it will be unable to regenerate and will stop producing cork. For this reason, cork harvesting is performed only by highly qualified professionals. The cork harvesting process consists of six stages:

1. Opening: Strike the cork vertically along the deepest crack in the bark. At the same time, twist the axe blade to separate the cork from the trunk.  

2. Splitting: The edge of the axe is inserted between the log and the split, followed by a slight twist of the axe to complete the split. 

3. Mark: Use a horizontal cut to define the size of the piece to be cut out. 

4. Extraction: The cork is extracted with the utmost care to prevent it from breaking. The larger the piece of cork extracted, the greater its commercial value. After extracting the first piece, the process is repeated until all the cork has been removed from the log. 

5. Removal: After the cork sheets are removed, some pieces of cork remain near the base of the trunk. To remove any parasites that may be present in the cork oak’s wedge, the cork harvester must tap the wedge with the eye of the axe.

6. Marked: At the end of the cork harvesting process, each tree is marked with the last two digits of the year in which the harvest took place; this makes it possible to calculate the year in which the process can be repeated.  

We use all the cork that is harvested, whether by using the scraps for byproducts or by recycling used cork products.