Cork is the bark of one tree, the cork oak, and taking it does not kill the tree. The first harvest waits until the tree is about twenty-five years old. After that the bark is stripped by hand every nine years, leaving the trunk bare and red, and it grows back. One tree can be harvested fifteen or so times in its life, and about half the world's cork comes from Portugal.
Inside, it is millions of tiny sealed cells full of air. That is why it is light, floats, keeps water out, feels warm in the hand and springs back when you press it. It seals a bottle, softens a floor and keeps a hot cup from marking a table. In a wallet it is light and soft, and it comes from a tree that is still standing.
