Holm oak, Quercus Ilex
The seed, e.g. the acorns, can be eaten raw or cooked. It can be sweet or bitter.
The seed is up to 3cm long, it can be dried, ground into a powder and used as a thickening in stews etc or mixed with cereals for making bread.
The seed from some trees contains bitter tannins, these can be leached out by thoroughly washing the seed in running water though many minerals will also be lost. Either the whole seed can be used or the seed can be dried and ground it into a powder. It can take several days or even weeks to properly leach whole seeds, one method was to wrap them in a cloth bag and place them in a stream. Leaching the powder is quicker. A simple taste test can tell when the tannin has been leached. The traditional method of preparing the seed was to bury it in boggy ground overwinter. The germinating seed was dug up in the spring when it would have lost most of its astringency.
The roasted seed is a coffee substitute.
An edible oil is obtained from the seed.
A mulch of the leaves repels slugs, grubs etc, though fresh leaves should not be used as these can inhibit plant growth.
Oak galls are excrescences that are sometimes produced in great numbers on the tree and are caused by the activity of the larvae of different insects. The insects live inside these galls, obtaining their nutrient therein. When the insect pupates and leaves, the gall can be used as a rich source of tannin, that can also be used as a dyestuff.
Very tolerant of maritime exposure and of trimming, it can be grown as a shelterbelt tree or hedge in maritime areas.
Wood - strong, hard, durable. Used for furniture. It makes a good charcoal and a good fuel, burning well even if green.
The bark is a source of tannin.