One piece cork

One piece cork is absolutely the most refined and it is used in high level applications, for example to closure luxury wines and spirits. 

For its realization, it’s necessary to use a monolithic piece of cork taken by hand directly from the bark of the tree. 
The operators specialized in harvesting cork use a very sharp axe.  Their work is the most delicate phase of the whole process: they train for roughly 8 years and are the highest paid agricultural workers in all of Europe.  During the harvest they shall chop off the bark without damaging the cambium layer of the trunk of the tree, otherwise the oak will be seriously harmed. These special operators shall balance force and sensibility and know all the physical characteristics of the cork tree.