Common Name: Turkey Oak

General Information

Quercus cerris is a deciduous tree with a dense, pyramidal crown; it usually grows 10 - 15 metres tall but can reach up to 40 metres. The bole can be 90 - 200cm in diameter, with old trees often developing several main stems[, ].
The tree is harvested from the wild for mainly local use as a food, medicine and source of materials, though sometimes the tree is harvested commercially for its wood. It is often grown as an ornamental and makes a good shade tree.

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

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Range

Central and southern Europe to W. Asia - France and Italy, west to Romania, Greece, Turkey, Syria and Lebanon

Habitat

Hedges, thickets and woods in acid soils[, ].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	15.00 m
Growth Rate	Fast
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Quercus cerris is a fairly cold-hardy plant, tolerating temperatures down to about -20°c when dormant.
Prefers a good deep fertile loam which can be on the stiff side[, ]. Grows best in a well-drained acidic soil[]. Prefers a sunny position, but young plants tolerate reasonable levels of side shade[, ]. Succeeds on a wide range of soils from weakly acid to somewhat alkaline[]. It grows well on chalk, even when the soil is shallow, so long as it is not dry[, , ]. Tolerates moderate exposure, surviving well but being somewhat stunted[]. Grows well near the coast[]. Established plants are very drought tolerant[]. Plants are tolerant of atmospheric pollution in cities[].
Intolerant of root disturbance, trees should be planted in their permanent positions whilst young[].
A very ornamental tree[], it grows very well in the maritime climate of Britain, where it is the fastest growing of the oaks in cultivation[].
The tree often produces large quantities of acorns[].
The seed ripens in its second year[].
A fast-growing oak, generally living for around 120 150 years[].
Trees respond well to coppicing and pollarding[].
Trees transplant badly unless they are moved regularly[].
Hybridizes freely with other members of the genus[].
This species is notably resistant to honey fungus[, ].

Edible Uses

Seed - cooked. Up to 25mm 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 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.

A sweet fluid exudes from insect damage on the stems and solidifies[, , , ]. This is edible and is sold as a manna in local markets in Iran[]. It can be boiled down into a syrup and used for sweetening food[].

Medicinal

Any galls produced on the tree are rich in tannins and therefore strongly astringent. They can be used in the treatment of various conditions including haemorrhages, chronic diarrhoea, dysentery, as a wash on cuts and wounds, as a mouthwash to treat toothache or gum problems etc[].

The plant (part not specified but the leaves, bark and galls are all rich in tannins and therefore likely to be used) is used in traditional Mediterranean medicine for the treatment of various conditions, including antiinfective treatments[].
There is some evidence that a tincture of the bark could be used internally against the pathogen Staphylococcus aureus[].

Agroforestry Uses:

The tree has a useful role to play in soil conservation, erosion control and the reforestation of bare soils because of its extensive root system and ability to establish and grow quickly in a range of soil types and conditions[].
Along the coastal mountain ranges of the Black Sea coast, Quercus cerris is quite an invasive species, forming coppice type of forests following the clear cutting of broad-leaved high forests. It has a tremendous capacity
of regeneration through suckers and easy establishment of young seedlings[].

Other Uses

The seed cups are used as buttons[].

The leaves of most species in this genus are more or less rich in tannins. A mulch of the partially decayed leaves can be placed around vulnerable plants in order to repel slugs, snails, grubs etc, and these will in time break down to add humus and nutrients to the soil. Fresh leaves should be used with caution, however, since as these decay they utilize some of the nitrogen in the soil and thus 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 and is also used by many cultures to make ink[, ].
The bark of oak trees is also usually rich in tannins and can be used as a dyestuff and for waterproofing rope[, ].

The leaves, bark and wood are used commercially as a source of tannins[].

The bark can be used as cork. It is somewhat inferior to the cork obtained from Quercus suber[]. The first removal of bark from older trees is brittle and hard, but a second removal of bark a few years later is of good quality, being soft, elastic and pliable[].

The wood is generally considered to be of little value, especially when harvested from the western parts of its range, though that from the east is of rather better quality and considerably more durable[, , ]. The wood has a tendency to crack, and is considered to be inferior to the wood obtained from Quercus robor or Quercus petraea[]. It valued by wheelwrights, turners and cabinet makers[]. It is mainly used for low-quality items such as shuttering and has also been used for railway sleepers[, , ]. It does not weather well[]. It is not desireable as a construction timber[].
The wood is a favoured fuel - burning well and giving off a lot of heat. It is also used to make 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.