What Are Corks?
Corks are a natural material used by humanity for over 5,000 years, primarily used for sealing containers but also employed as insulation, fishing rods, floats and even for footwear.
Corks are made from the stripped bark of the Cork Oak (Quercus suber). Native to southwest Europe and northwest Africa; the majority of the worlds cork is grown in Portugal, Spain, Morocco and Algeria. Cork Oak bark can only be harvested once the tree has reached 25 years in age. Subsequent harvesting is done once every 9-13 years. Cork Oaks can live to be 300 years old. 
The cellular construction of cork, which contains over 200 million individual closed cells per cubic inch, is impervious to water and enables it to compress and recover easily. Due to the presence of the phenolic compound Suberin, cork is naturally anti-microbial and suppresses the growth of mold, fungus, and bacteria.
Due to the expertise and care it requires, the extraction of cork is one of the most well paid agricultural enterprises in the world. Cork harvesting is done entirely without machinery.
Cork Oak forests contain one of the worlds highest levels of forest biodiversity including endemic plants and endangered species such as the Iberian Lynx, the Iberian Imperial Eagle, and the Barberry Deer. These forests provide a defense against the desertification of the region.
The largest cork tree in the world can be found in the Portuguese town of Aquas de Moura. Known as “The Whistler Tree”, it is over 230 years old with a height of more than 45 feet.
It is illegal to cut down a Cork Oak in Portugal.