Where does cork come from?

Cork is the thick and spongy bark of the cork oak tree. These trees don’t grow to be very tall but they have quite thick trunks. Taking the cork bark off the tree can only be done every ten years, but about forty-five pounds, or about twenty-two kilograms of cork can be stripped off one tree at a time, so that every ten years a plantation of cork oaks can give a very high harvest.