CORK CORK Cork is the bark of the cork oak tree; it is a completely natural raw material. It is a sustainable and renewable resource because the cork tree is not cut down, only the bark is stripped to harvest the cork, after which the tree immediately begins to grow a new bark. Once the cork oak tree reaches the age of 25 years, the cork can be stripped from the trunk every nine years. An oak tree lives for about 200-300 years. Furthermore, it is completely biodegradable and recyclable. Cork is lightweight, impermeable to liquids and gases, elastic and compressible, and provides thermal and acoustic insulation. Because of these characteristics, it is used in a variety of products. When the harvested bark is of high quality it is known as "gentle" cork, and it is used to make stoppers for wine and champagne bottles. However, the first harvest called "virgin" cork usually produces lower quality material. These sheets of cork – along with the used stoppers that are collected – are grounded up and manufactured into new cork products like floors, shoes, cork boards, insulation and other products.