Quercus robur

What to Eat

Edible parts: Gum, Seeds, Nuts, Manna, Seeds - coffee, Leaves - flavouring

The seed must be cooked before eating — it is nourishing but indigestible. Chopped and roasted, it can be used as an almond substitute. It can also be dried and ground into a powder to thicken stews or mixed with cereals for bread-making. Bitter tannins can be leached out by thoroughly washing in running water, though minerals are lost in the process. Either whole seeds or ground powder can be leached — whole seeds may take several days or weeks, and placing them in a cloth bag in a running stream was a traditional method. Ground powder leaches faster. A simple taste test confirms when tannin has been sufficiently removed. Seeds were traditionally buried in boggy ground over winter and dug up in spring when most astringency had faded. The roasted seed also makes a coffee substitute. An edible gum is obtained from the bark. One report mentions that an edible manna is obtained from the plant and used as a butter substitute in cooking, though this likely refers to the same gum.

Known Hazards

Where to Find It

It is a temperate plant. It is native to Europe. It suits light soils. It does well in fertile alkaline soils. It suits hardiness zones 3-10. Arboretum Tasmania. National Arboretum Canberra.

Africa, Australia, Balkans, Belarus, Bosnia, Britain, Bulgaria, Canada, Central Asia, Chile, China, Czech Republic, East Africa, Estonia, Europe, Falklands, France, Germany, Greece, Hungary, Iran, Latvia, Libya, Lithuania, Luxembourg, Mediterranean, Middle East, Netherlands, North America, Pakistan, Poland, Portugal, Romania, Russia, Slovenia, South Africa, Southern Africa, South America, Spain, St Helena, Sweden, Tajikistan, Tasmania, Turkey, Türkiye, Ukraine, USA, Zimbabwe,

How to Identify

A tree with large branches. It grows 36 m high and spreads 25 m across. The crown is broad and often an irregular shape. It loses its leaves during the year. The young bark is smooth and shiny but becomes cracked. The young branches are hairy. The leaves are 5-17 cm long by 2-10 cm wide. The leaves are deep green and almost without leaf stalks. The leaves have rounded lobes. There are 5-7 lobes on each side. The acorns are carried singly or in clusters of 2 or 3. The female flower occurs in the axils of leaves near the tip of young branches. The cup encloses about 1/3 of the nut. The nut is oval and 1.5-1.8 cm long by 1-1.3 cm wide.

How to Grow

Prefers a good deep fertile loam which can be on the stiff side. Young plants tolerate reasonable levels of side shade. Succeeds in heavy clay soils and in wet soils so long as the ground is not water-logged for long periods. Dislikes dry or shallow soils but is otherwise drought tolerant once it is established. Tolerant of exposed sites though it dislikes salt-laden winds. The oak is a very important timber tree in Britain, it is also a very important food plant for the caterpillars of many species of butterfly, there are 284 insect species associated with this tree. It has often been coppiced or pollarded for its wood in the past, though this should not be done too frequently, about once every 50 years is the average. The tree flowers on new growth produced in spring, the seed ripening in its first year. Older trees have a thick corky bark and this can protect them from forest fires, young trees will often regenerate from the base if cut down or killed back by a fire. Intolerant of root disturbance, trees should be planted in their permanent positions whilst young. Hybridizes freely with other members of the genus. Immune to attacks by the tortix moth. This species is notably resistant to honey fungus.

Propagation: Seed loses viability quickly if allowed to dry out. It can be stored moist and cool over winter, but is best sown as soon as it is ripe in an outdoor seed bed with protection from mice and squirrels. Small quantities can be sown in deep pots in a cold frame. Because plants develop a deep taproot early, they should be moved to permanent positions as soon as possible — seeds sown in situ produce the best trees. Trees left in a nursery bed for more than 2 growing seasons transplant very badly.

Medicinal Uses

The oak has a long history of medicinal use, being anti-inflammatory, antiseptic, astringent, decongestant, haemostatic, and tonic. The bark is the most commonly used part, though galls, seeds, and seed cups are also sometimes employed. A decoction of the bark is used for chronic diarrhoea, dysentery, intermittent fevers, and haemorrhages. Externally it is applied to wounds, skin eruptions, sweaty feet, and piles, and used as a vaginal douche for genital inflammations and discharge, and as a wash for throat and mouth infections. Bark is harvested from branches 5–12 years old and dried for later use. Galls on the tree are strongly astringent and used to treat haemorrhages, chronic diarrhoea, and dysentery. The plant is used in Bach flower remedies, prescribed for the states of 'Despondency' and 'Despair, but never ceasing effort'. A homeopathic remedy made from the bark addresses disorders of the spleen and gall bladder. The German Commission E Monographs approve Quercus robur for coughs and bronchitis, diarrhoea, inflammation of the mouth and pharynx, and inflammation of the skin.

Other Uses

A mulch of leaves repels slugs and grubs, though fresh leaves should not be used as they can inhibit plant growth. The bark is an ingredient of 'Quick Return' herbal compost activator — a dried and powdered herbal mixture added to compost heaps to stimulate bacterial activity and shorten composting time. The bark is also very rich in calcium. Oak galls produced by insect larvae are a rich source of tannin once the insects have left, and also serve as a dyestuff. A black dye and an excellent, long-lasting ink are made from the galls mixed with salts of iron, though the colour is not very durable. With alum the dye turns brown; with salts of tin it becomes yellow. A purplish dye is obtained from an infusion of bark with a small quantity of copperas — not bright but said to be durable. Tannin is extracted commercially from the bark and is also found in the leaves — on a 10% moisture basis, bark contains 11.6% tannin and wood 9.2%. Bark strips easily from the wood in April and May. The wood yields tar, quaiacol, acetic acid, creosote, and tannin. The wood itself is hard, tough, and durable even under water, highly valued for furniture and construction, and also makes good fuel and charcoal. Trees can be coppiced for basket making, fuel, and construction.

Quercus robur, the pedunculate (or "English") oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native to most of Europe, North Africa and western Asia, and is widely cultivated in other temperate regions. It grows on soils of near neutral acidity in the lowlands and is notable for its value to natural ecosystems, supporting a very wide diversity of herbivorous insects and other pests, predators and pathogens.

Production

It can live for several hundred years. n

Notes

There are about 600 Quercus species. It is cultivated in China.

More from Fagaceae

Castanea alnifolia

Bush chinkapin, Florida chinkapin, Trailing chinkapin, Downy chinquapin

Castanea crenata

Japanese chestnut

Castanea dentata

American chestnut, American sweet chestnut

Castanea henryi

Zhui li, Conic chestnut

Castanea mollissima

Chinese chestnut

Castanea ozarkensis

Ozark chinkapin, Ozark chestnut