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Cork, the bark of the cork oak tree (Quercus suber L.), is the main raw material sourced from the Cork Oak Forest. Its 100% natural vegetable tissue consists of microscopic honeycomb cells filled with gas similar to air and covered in suberin and lignin. Polysaccharides, ceroids, and tannins are some of the minor compounds in cork’s chemical composition.
It is not known precisely when cork first began to be used although documents point to ancient Egypt. The widespread use of cork as a material and the production of cork bottle stoppers also escapes precise dating although registries of the first producers of cork bottle stoppers in Portugal is not more than 250 years old.
As a material, cork has wide uses such as shuttles, in the automotive industry, musical instruments, sport equipment, pieces of art, decoration and furniture, and building material, among many things. Despite the wide variety of cork products available, it is the famous cork used as a bottle stopper that drives the industry: its production accounts for 70% of the cork market value.
Harvesting the cork oak tree means stripping the bark from its trunk, and that marks the beginning of cork’s life cycle. Harvesting takes place during the cork’s fastest growing period, usually from mid May to late August. But the tree won’t be profitable and won’t produce harvestable cork for the first 25 years, and in order to be harvested, the trunk’s circumference will have to be approximately 70 cm wide and 1,3m from the soil. The exploitation of the cork oak tree lasts approximately 150 years.