Photographer's Note

The cork oak (Quercus suber; in Portuguese: sobreiro) is a native tree of the Mediterranean region (southwest Europe and northwest Africa). It is an evergreen tree, that grows to up to 20 m, very well adapted to the hot summers and resistant to wildfires.
The main produce of the sobreiro is its thick outer bark, that is cork (in Portuguese: cortiça).
Cork is an amazing natural product: light-weight, insulating, flexible, resistant, waterproof, fire-resistant, floatable, etc. Perhaps its most known use is for bottle stopper, especially wine bottles. But the uses of cork range from wall decoration, high-tech insulator, handicrafts and even clothes.
Portugal is the biggest cork producer in the world (50% of the world harvest). Cork oak trees cover a large expanse of the countryside, especially in the southern provinces. The tree is protected by law and can be cut only in very special cases, subject to authorization.
The cork bark is harvested (removed) every nine years. The harvesting doesn't harm the tree. Along those years the bark grows again and changes color, thickness and texture. When the old cork is harvested, the inner bark presents the reddish or light brown color you see here; these oaks had the cork harvested a few days before the photo.
An even less known product of the cork oak is its fruit, the acorn (in Portuguese: bolota or lande). This nut is not so tasty for human consumption, but it is excellent food for pigs and other swine, which roam freely the areas of cork oaks and holm oak (Quercus ilex, a similar tree but without corky bark). Pork fed on acorn is specially tasty.
The workshop #1 presents a complete tree and was my first choice for this post. But afterwards I changed my mind to the actual primary post, as you have a better view of the subject.
For a even better detail of the old cork and the new bark and the cut edge between them, please see workshop #2.
This picture was shot near the ghetto of Quinta da Princesa.
Approximate location: 38.632553, -9.1277987.
Edits: 1. After a question of Gonçalo (Bluejeans) (about after harvesting, the new bark becoming red like blood) I decided to post another workshop (#3); it's another tree, in a different location (in Pegões Gare, Sep. 22, 2007) and I'm sure the old cork was harvested much more days or weeks before than the photo of primary post and other workshops. That is, the color changes over time, from light brown (or dark yellow), to red or reddish brown, to dark brown and eventually to some hues of gray after a few years. About the bloody lines (still discernible in this workshop), I guess it has relation to the sap of the tree or some inter-bark fluid. This shot is near the ground.
2. José (stego) corrected me about the acorns in Portuguese: lande is the acorn of the cork oak (Quercus suber), while the bolota or boleta is the acorn of the holm oak (Quercus ilex). José adds, correctly, that the bolota is tastier than the lande and almost as good as chesnuts (castanha in Portuguese; the fruits of Castanea sativa). Yes, I've eaten bolotas. The swine eat both, landes and bolotas, but it seems they prefer the tastier bolotas.

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Additional Photos by Francisco Santos (xuaxo) Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 4896 W: 319 N: 4862] (6854)
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