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Quercus suber - L.

Cork Oak

Author	L.	Botanical references	11, 50, 200
Family	Fagaceae	Genus	Quercus
Synonyms
Known Hazards	None known
Range	S. Europe to N. Africa.
Habitat	Siliceous hills on the littoral[89].
Edibility Rating	2 (1-5)	Medicinal Rating	2 (1-5)

Physical Characteristics

An evergreen Tree growing to 20m by 15m at a slow rate.

The plant prefers medium (loamy) and heavy (clay) soils. The plant prefers acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It requires moist soil. The plant can tolerates strong winds but not maritime exposure.

Habitats

Woodland Garden; Canopy;

Edible Uses

Edible Parts: Seed.

Edible Uses: Coffee.

Seed - cooked[105]. A famine food[177]. 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 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.

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Astringent.

Any galls produced on the tree are strongly astringent and can be used in the treatment of haemorrhages, chronic diarrhoea, dysentery etc[4].

Other Uses

Cork; Repellent; Shelterbelt; Tannin; Wood.

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[4]. A fairly wind-tolerant tree, it can be used in shelterbelt plantings[200]. Bark is the source of cork, it is much used for heat and sound insulation, flooring, floats etc. Trees are first harvested when they are 25 - 30 years old[74], and then harvested every 6 - 12 years[117]. The bark must be removed carefully so as not to harm the tree. A large tree can yield up to 1 tonne of cork. On a 10% moisture basis, the bark contains 16.9% tannin[223]. Wood.

Cultivation details

Prefers a good deep fertile loam which can be on the stiff side[11]. Lime tolerant[188]. Young plants tolerate reasonable levels of side shade[200]. Tolerates moderate exposure, surviving well but being somewhat stunted[200]. Cultivated for its bark in Europe, it is the main source of cork[50, 89]. Trees are first harvested when they are 25 - 30 years old and are then harvested on a 10 - 12 year rotation. Only hardy in the milder areas of Britain[200], it is not very frost resistant[98]. Trees grow well in Cornwall where there are many large specimens[11, 49, 59]. Trees grow quite well at Kew[K]. Transplants badly unless it is moved regularly, it should only be moved in September or as growth commences in late spring[11]. Does not fruit well in Britain. Most of the trees grown in Britain as Q. suber are in fact Q. suber occidentalis[11]. Hybridizes freely with other members of the genus[200]. This species is notably resistant to honey fungus[88, 200].

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[11]. Trees should not be left in a nursery bed for more than 2 growing seasons without being moved or they will transplant very badly.

Links

References

[K] Ken Fern
Notes from observations, tasting etc at Plants For A Future and on field trips.

[4] Grieve. A Modern Herbal. Penguin 1984 ISBN 0-14-046-440-9
Not so modern (1930's?) but lots of information, mainly temperate plants.

[11] Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981
A classic with a wealth of information on the plants, but poor on pictures.

[49] Arnold-Forster. Shrubs for the Milder Counties. 0
Trees and shrubs that grow well in Cornwall and other mild areas of Britain. Fairly good, a standard reference book.

[50] ? Flora Europaea Cambridge University Press 1964
An immense work in 6 volumes (including the index). The standard reference flora for europe, it is very terse though and with very little extra information. Not for the casual reader.

[59] Thurston. Trees and Shrubs in Cornwall. 0
Trees and shrubs that succeed in Cornwall based on the authors own observations. Good but rather dated.

[74] Komarov. V. L. Flora of the USSR. Israel Program for Scientific Translation 1968
An immense (25 or more large volumes) and not yet completed translation of the Russian flora. Full of information on plant uses and habitats but heavy going for casual readers.

[88] RHS. The Garden. Volume 112. Royal Horticultural Society 1987
Snippets of information from the magazine of the RHS. In particular, there are articles on plants that are resistant to honey fungus, oriental vegetables, Cimicifuga spp, Passiflora species and Cucurbits.

[89] Polunin. O. and Huxley. A. Flowers of the Mediterranean. Hogarth Press 1987 ISBN 0-7012-0784-1
A very readable pocket flora that is well illustrated. Gives some information on plant uses.

[98] Gordon. A. G. and Rowe. D. C. f. Seed Manual for Ornamental Trees and Shrubs. 0
Very comprehensive guide to growing trees and shrubs from seed. Not for the casual reader.

[105] Tanaka. T. Tanaka's Cyclopaedia of Edible Plants of the World. Keigaku Publishing 1976
The most comprehensive guide to edible plants I've come across. Only the briefest entry for each species, though, and some of the entries are more than a little dubious. Not for the casual reader.

[117] Rosengarten. jnr. F. The Book of Edible Nuts. Walker & Co. 1984 ISBN 0802707699
A very readable and comprehensive guide. Well illustrated.

[177] Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984 ISBN 3874292169
An excellent book for the dedicated. A comprehensive listing of latin names with a brief list of edible parts.

[188] Brickell. C. The RHS Gardener's Encyclopedia of Plants and Flowers Dorling Kindersley Publishers Ltd. 1990 ISBN 0-86318-386-7
Excellent range of photographs, some cultivation details but very little information on plant uses.

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992 ISBN 0-333-47494-5
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.

[223] Rottsieper. E.H.W. Vegetable Tannins The Forestal Land, Timber and Railways Co. Ltd. 1946
A fairly detailed treatise on the major sources of vegetable tannins.

Readers Comments

Plants for a Future does not verify the accuracy of reader comments, use at your own risk. In particular Plants For A Future can not take any responsibility for any adverse effects from the use of plants. You should always consult a professional before using plants medicinally.

Quercus suber

Peter Gibbons Thu Jan 19 2006

SunnyGardens.com Find additional information for this plant at SunnyGardens.com.

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