Cork is harvested in a steady cycle that promotes healthy growth to the tree over its expected lifespan of over 200 years. Cork suitable for wine stoppers is not harvested until the following 9-12 year cycle, so farmers have invested over 40 years before natural wine corks are produced.
Cork bark is removed from trees in spring or summer.
At this time of year the cork comes away easily from the trunk because the tree is growing, the new, tender cork cells being generated break easily. Harvest difficulties occur if the process is not carried out when the tree is in full growth. As soon as it is evident that the cork is being stripped too early or too late in the season the stripping is brought to a halt, a year s delay in cork extraction is preferred to damage to the tree. There have been five consecutive below average rainfall years in the Mediterranean area. During drought periods the trees are less willing to relinquish their bark.