How is cork harvested from cork oak trees?

Commercial cork is harvested from the cork oak (Quercus suber) through a manual process that does not harm the tree's vital inner bark.1

The harvesting process involves the following steps:

• Preparation: The tree is typically first stripped when it reaches about 20 to 25 years of age. This initial bark is rough and of little commercial value.12
• Extraction: Skilled workers use hand tools, such as levers and wedges, to cut slits into the outer bark. The bark is then carefully pried loose and peeled away from the inner bark, with great care taken to avoid damaging the tree's deeper regenerative layers.1
• Regeneration: Because the inner bark contains uniform regenerative tissue, the tree naturally grows a new layer of cork. In a healthy tree, a new, uniform sheath of 2.5–5 cm (1–2 inches) forms every 3 to 10 years, allowing for repeated harvests over the tree's average 150-year lifespan.1
• Processing: Once removed, the cork slabs are boiled or steamed to increase flexibility and remove soluble tannic acids. Finally, the rough woody surface is scraped clean by hand for distribution.1