The Cork Oak is the only tree in the world that will not die when you strip the bark from the tree. In fact, if done only once every ten years or so and it helps the tree thrive and live for more than 200 years on average.
Once the tree reaches a minimum age of 25 (some even say 45) years the cork bark is not at its best quality and so is not harvested. At harvesting age, the bark is stripped from the tree with an axe by a skilled cork worker in uniform sheets and taken by the truckload to the factory.
Once in the factory the cork sheets are boiled in water to break down the cell structure and make the bark easier to work with. After they are dried the cork is shaved from the top in very thin sheets similar to the width of tissue paper. In this state the cork is almost transparent. This is the top layer of the cork fabric and it is glued to the backing fabric which is most commonly a cotton/polyester blend that is in a similar color shade as the cork. These sheets of cork "tissue paper" are placed together like patch work on the fabric and this is the reason for the various colors and patterns seen on the fabric when viewing close up.
Different cork grain sizes and distinctive formulations of binders are used in the manufacturing process to create composition cork rolls and sheets in grades and appearances to satisfy specific purposes and uses.