In countries like Italy, France, Spain and Portugal you find a lot of corktrees.
It could easily be millions.
Corktrees are stripped from there bast every 9 years.
But they don'care and just start all over again "creating" new bast and cork.
And often there are cattle in those same fields.
I visited a cork tradingcompany in Cortegana, Spain.
But how do trees grow anyway, being a lot of hard wood ?
This picture shows you the fundamental setup of trees.
And the cambium does the trick !
The bark is the living part of the trunk, just under the cork.
In the bark (at the inside) is the cambium (3 and 4 are actually one 2-layer item).
The cambium has cells that split up, but it has 3 different types of cells.
Cells that split into cambium cells plus wood cells (inwards type),
cells that split into cambium cells only (sideways)
and cells that all become bark cells (outwards).
The inwards growing cells of the cambium (3) make the sapwood (2) grow in diameter, so in circumference.
That means the cambium (3) itself must grow sideways to keep up with that extra circumference.
Ofcourse the cork (5) must also be kept intact since it is the sole protection for the tree.
Therefor the cambium (3) also makes extra cells growing outwards to help the cork grow bigger(5).
However, the cork is the last layer towards the "world" and so it dries out and dies out there.
That is the reason cork has cracks in it (most trees).
Or, at certain trees that have a flat corklayer (platanes, birchtrees), that corksheet tears apart.