The myriad properties of the bark of the cork oak never cease to amaze scientists, protecting the tree from fire and enabling its renewal. The life cycle of the tree spans generations and provides for the sustainability of the environment, since all harvesting, or stripping, is done by hand, with great care, thus safeguarding the tree and protecting the environment. The capacity of the cork oak for re- generation is such that, with no need for herbicides, fertilizers or irrigation, in the nine-year interval between strippings, the bark is fully restored and cork can be harvested once again.
Like all trees, the cork oak produces oxygen, but its unique cell structure prevents the emission of carbon dioxide, largely responsible for global warming. Cork industry operations provide for the sustainability of cork oak forests and help protect the wildlife and flora that inhabit them. The stripping of the bark without harming the tree is a unique process deriving from the singular anatomy and properties of the outer bark layer, or periderm. When cork is harvested, in late spring and summer, it is essential that the cells that produce it (phellogen) are active and keep dividing, enabling the cork to be removed from the tree without damaging it.
The cork oak is amazing: long-living, with an incredible capacity for regeneration. It lives on average for 150 to 200 years despite the bark being stripped many times during its life: a total of about 16 times, at nine-year intervals. This material, harvested with great care, is endowed with unique properties that human ingenuity has so far been unable to reproduce or surpass, being: • extremely light
• impermeable to liquids and gases
• elastic and compressible
• an excellent thermal and acoustic insulator
• flammable, but smoldering rather than burning • extremely resistant to friction