Common Name:

General Information

Quercus pyrenaica is a deciduous tree with a wide, much-branched, irregular crown; it can grow 20 - 25 metres tall. The bole is usually tall, straight and slender[].
The tree is harvested from the wild on a commercial basis for its wood, and on a local basis as a source of medicines and materials, possibly also as a food. It is sometimes grown as an ornamental in parks and gardens.

Known Hazards

All parts of the plant contain tannins. Whilst tannins are found in many foods, and have a range of medicinal uses. They are usually only present in low concentrations. In some foods made from oaks (particularly the seeds), the tannin content can be quite high unless the food is treated to reduce tannin content.
Tannins are only of low toxicity and, because of their bitter taste and astringency, are unlikely to be eaten in large quantities. However, if they are taken in excess, they can cause stomach pains; constipation followed by bloody diarrhoea: excessive thirst; and excessive urination[].

Botanical References

Range

Southwestern Europe - Portugal, Spain, France, Italy[ N. Africa - Morocco

Habitat

Usually a dominant species in deciduous and mixed deciduous evergreen forests, mainly on silicious soils; at elevations from sea level to more than 2,000 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	18.00 m
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Quercus pyrenaica is generally found in areas with a mean annual rainfall around 600mm, with at least 100mm falling during the summer[].
Succeeds in full sun, but appreciates some shade, especially in hot weather[]. Grows best in loose soils with a sandy texture[]. Found mainly in siliceous soils, occasionally in limestones or dolomite[]. Established trees are somewhat drought tolerant[].
The tree is grown as an ornamental shade tree - there are some named forms[].
The seed ripens in its first year of growth[].
Trees can live for around 300 years[].
Trees respond well to coppicing and pollarding[].

Edible Uses

The seed can be up to 40mm long and 10 - 25mm wide[].
Although we have no specific information for this species, the seeds of all the species of oak are edible - indeed, several species have been used as staple foods, whilst most if not all have been used for food in times of shortage, when better foods were not available[].
The seed is usually cooked before eating, though it can also be eaten raw. It can be eaten whole, though it is more commonly dried, then ground into a powder and used as a thickening in stews etc or mixed with cereals for making bread.
In some species, especially many of those classified as 'white oaks', the seeds are low in tannins and have a more or less sweet and agreeable flavour. The seed of most species, however, have a very bitter flavour, due especially to the presence of tannins. In these species there are various processes that can remove or at least reduce the amount of these bitter substances (although other water-soluble substances, including some minerals, will also be removed).
Tannins are water-soluble and therefore the easiest way to remove or reduce tannin levels is by soaking in water. A few different methods are listed:-
A traditional method of preparing the seed was to bury it in boggy ground overwinter and allow the wet soil to gradually leach the tannins. The germinating seed was dug up in the spring when it would have lost most of its astringency and bitterness.
Another method was to wrap the seeds in a cloth bag and place them in a stream for several weeks.
Drying the seed and grinding it to a powder before soaking speeds up the process. The fastest method is to use hot water, by cooking the powder and changing the water several times until the cooking water is no longer bitter. Alternatively, you can use cold water (which is reported to produce the best quality flour). In this case, you soak the powdered seed in cold water for 12 - 24 hours then discard the water. Repeat this process for a number of times until the soak water is no longer bitter.

The roasted seed of many Quercus species has been used as a coffee substitute.

Medicinal

Quercus (oak) species are used in the traditional medicine of many cultures, being valued especially for their tannins. Various parts of the plant can be used, most frequently it is the leaves, bark, seeds, seed cups or the galls that are produced as a result of insect damage. A decoction or infusion is astringent, antibacterial, antifungal, antiseptic, styptic and haemostatic. It is taken internally to treat conditions such as acute diarrhea, dysentery and haemorrhages. Externally, it is used as a mouthwash to treat toothache or gum problems and is applied topically as a wash on cuts, burns, various skin problems, haemorrhoids and oral, genital and anal mucosa inflammation[]. Extracts of the plant can be added to ointments and used for the healing of cuts[, ].

Other Uses

The leaves of most species in this genus are more or less rich in tannins. A mulch of the leaves can be placed around vulnerable plants in order to repel slugs, snails, grubs etc. Fresh leaves should be used with caution, since these can utilize some of the nitrogen in the soil and this 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[].
The bark is rich in tannins[].

The wood is heavy, hard, tough, durable, but is considered to be inferior to the wood obtained from Quercus robor or Quercus petraea. It is also less useful because its trunk is not very thick and is more irregular. It is used mainly for poles and railway sleepers, and would probably be useful in cooperage[].
The wood is a very good fuel, burning well and giving off a good heat. It can also be used to make a good quality charcoal[].

Propagation

Seed - it quickly loses viability if it is allowed to dry out. It can be stored moist and cool overwinter but is best sown as soon as it is ripe in an outdoor seed bed, though it must be protected from mice, squirrels etc. Small quantities of seed can be sown in deep pots in a cold frame. Plants produce a deep taproot and need to be planted out into their permanent positions as soon as possible, in fact seed sown in situ will produce the best trees[]. Trees should not be left in a nursery bed for more than 2 growing seasons without being moved or they will transplant very badly.