The cork oak is the only plant species capable of producing cork in a sustainable manner and with the highest quality, resulting in an industry that is unique in the world, and that is vital for the maintenance of the montado and the preservation of the flora and fauna. It is a tree with voluminous bark with suberose tissue (the cork); it has green foliage all year round, and can reach up to 10 to 15 meters in height when adult. It has good longevity and an enormous capacity for regeneration.