Cork is a material that grows as the bark of the Cork Oak tree.  More than half of the world's supply originates in southern Portugal.  The bark of the tree is harvested about every 9 or 10 years, and it is allowed to dry for 1 to 2 years.  Next it is boiled to remove any toxins or other harmful agents, and then it is graded and cut.  After a final cleaning and drying, the cork is sorted and ready for use.  Cork is most commonly used for wine bottle stoppers, but it can also be found in bulletin boards, flotation devices, and floor tiles.  Worldwide, demand is on the rise primarily due to increasing wine consumption.  Ramping up production, however, is a lengthy process since the trees can only be harvested about once per decade.  Synthetic cork has been developed to satiate the growing demand.