Oak

Description

Oak is the common name for many acorn-producing trees and shrubs that are members of the beech, or Fagaceae, family. Oak trees are classified as members of the genus Quercus, a Latin word said to be derived from a Celtic word meaning "fine tree." Worldwide there are more than 600 different species of oak. They thrive across the Northern Hemisphere in China, Japan, Europe, the British Isles, and in all of the continental United States except for Alaska. More than half of the 600 species are native to North America. Yet only about 60 varieties grow north of Mexico. In the forests of northern areas that have short summer growing seasons and long winters, such as Canada, northern Europe, and Siberia, varieties of oak are very scarce.

The oak family is a diverse group of trees and shrubs, influenced by climatic and environmental changes. Recent studies indicate that global warming contributes to oak dieback by speeding up the reproduction of beetles and fungi that attack oak trees. There are oaks that grow to heights of about 100 ft (30.5 m), while other types never grow larger than a small shrub. In warmer climates, oaks are evergreens, keep their leaves all year long, and are often used as ornamental trees in parks. In colder climates, they usually drop their leaves in autumn.

Many of these deciduous oaks have leaves that turn brilliant gold or scarlet in the autumn. In spring small, yellow green flowers appear. The male flowers hang in clusters called catkins and have profuse amounts of pollen. This oak pollen is carried by the wind to fertilize female flowers that produce acorns. Oak trees grow very slowly. In 80 years, it's estimated that one will grow to no more than 2 ft (0.6 m) in diameter. Oaks do not even produce acorns for their first 20 years, but they live a very long time. Average life expectancy for most oaks is between 200 and 400 years, and there are oak trees over 800 years old that are still alive.

Oaks are divided into two basic categories: white and red. The leaves of most of these are characteristically lobed, and depending upon the variety, can have anywhere from five to 11 lobes. Historically, the oak has been considered sacred by many civilizations. Abraham's Oak, the Oak of Mamre, is thought to be on the spot where the bible states Abraham pitched his tent. Legend states that anyone defacing this tree will lose their firstborn son. Both the ancient Greeks and Romans revered the oak, but its longest association has been with the British Isles. The Druids considered it to have both medicinal and mystical significance. For centuries, an oak sprig was inscribed on English coins. Legend states that King Arthur's round table was made from one gigantic slice of a very ancient oak tree. Oak has been used as a medicine since the ancient Greek and Roman times. The famous Roman doctor Galen first used oak leaves to heal wounds .

The American white oak, Quercus alba, and the English oak, Quercus robur, have bark with similar healing qualities. Oak bark contains saponins, tannins, calcium oxalate, starch, glycosides, oak-red, resin, pectin, levulin, and quercitol.

General use

Oak wood as timber is prized for its strength, elasticity, and durability. It is ideal for making furniture, barrels, railroad ties, and in the past, ships. Oak acorns are a source of food for wildlife and have been used as fodder for farm animals in the past. A flour made from ground acorns was also a part of the diet of Native Americans. The tannin in oak bark is used in leather preparation. Cork is made from the bark of some species that grow only in Spain and Portugal.

Recent advances in molecular genetics have shown that DNA from samples of oak can be isolated and analyzed. This type of analysis has a variety of potential applications in archaeology and forensic investigations.

Oak used to make wine barrels has been found to increase the antioxidant activity of wines aged in the barrels as well as adding a distinctive aroma to the wine. The increase in antioxidant activity can be measured by a new technique known as electron paramagnetic resonance, or EPR.

Oak bark is used in medicine as a bowel astringent to treat diarrhea and as an anti-inflammatory gargle for soothing sore throats. It can be used topically for such skin inflammations as dermatitis , as an enema for hemorrhoids , or as a douche for vaginal infections and leukorrhea. A study in 1980 showed some evidence that oak bark may prevent kidney stone formation and act as a diuretic. A 1990 Russian study demonstrated that oak bark had antibacterial activity against Staphylococcus. One study in 1994 showed that oak bark could reduce serum cholesterol levels in animals.

Preparations

One teaspoonful of pulverized oak bark powder can be added to 1 cup of water, boiled, and then simmered at a reduced heat for 15 minutes to make an oak bark tea. This tea can be taken internally as an intestinal astringent up to three times per day. Oak bark is also available in both an extract and a tincture. For rinses, compresses, and gargles, 20 g of pulverized bark should be dissolved in 1 qt (1 L) of water, and prepared in the same manner as the tea. Oak bark is also available as snuff, tablets, and capsules.

Precautions

Oak bark should not be used externally over large areas of skin damage or used as a full bath. Oak bark for gargles, enemas, or douches should not be used for more than two weeks before consulting a doctor. A doctor should also be consulted for any episode of diarrhea that lasts longer than three days despite treatment with oak bark.

Side effects

No side effects have been reported when oak preparations are used at recommended dosage levels. Patients occasionally experience mild stomach upset or constipation if the dosage is exceeded.

Interactions

Oak bark preparations are believed to inhibit or reduce the absorption of such alkaline drugs as antacids. In addition, oak bark has been found to reduce the effectiveness of codeine and atropine.

Resources

BOOKS

Grieve, M., and C. F. Leyel. A Modern Herbal: The Medical, Culinary, Cosmetic and Economic Properties, Cultivation and Folklore of Herbs, Grasses, Fungi, Shrubs and Trees With All of Their Modern Scientific Uses. Barnes and Noble Publishing, 1992.

Hoffman, David, and Linda Quayle. The Complete Illustrated Herbal: A Safe and Practical Guide to Making and Using Herbal Remedies. Barnes and Noble Publishing, 1999.

PERIODICALS

Deguilloux, M. F., M. H. Pemonge, and R. J. Petit. "Novel Perspectives in Wood Certification and Forensics: Dry Wood as a Source of DNA." Proceedings of the Royal Society of London, Series B, Biological Sciences 269 (May 22, 2002): 1039-1046.

Diaz-Playa, E. M., J. R. Reyero, F. Pardo et al. "Influence of Oak Wood on the Aromatic Composition and Quality of Wines with Different Tannin Contents." Journal of Agriculture and Food Chemistry 50 (April 24, 2002): 2622-2626.

Kamata, N., N. Kamata, K. Esaki, et al. "Potential Impact of Global Warming on Deciduous Oak Dieback Caused by Ambrosia Fungus Raffaelea sp. Carried by Ambrosia Beetle Platypus quercivorus (Coleoptera: Platypodidae) in Japan." Bulletin of Entomological Research 92 (April 2002): 119-126.

Troup, G. J., and C. R. Hunter. "EPR, Free Radicals, Wine, and the Industry: Some Achievements." Annual of the New York Academy of Science (May 2002): 345-347.

ORGANIZATIONS

Herbal Advisor. http//www.AllHerb.com

OnHealthHerbal Index. "Oak Bark." http//www.OnHealth.com

Joan Schonbeck

Rebecca J. Frey, PhD

oak any tree or shrub of the genus Quercus of the family Fagaceae ( beech family). This complex genus includes as many as 600, found chiefly in north temperate zones and also in Polynesia. The more southerly species, ranging into the tropics, are usually evergreen. Oaks are cultivated for ornament and are prized as the major source of hardwood lumber. The wood is durable, tough, and attractively grained; it is especially valued in shipbuilding and construction and for flooring, furniture, railroad ties, barrels, tool handles, and veneer (particularly highly burled oak). The oaks are commonly divided into two groups, the black (or red) and the white. The former (e.g., the scarlet, pin, Spanish, willow, laurel, and shingle oaks) are characterized by leaves with sharp-tipped lobes and by acorns that mature in two years. The white oaks (e.g., the white, post, bur, cork, and holly oaks) are characterized by smooth-lobed leaves and acorns that mature in one year. Q. alba, the white oak, is the most important timber tree of the oak genus. Lumber-yielding species of chestnut (genus Castanea ) are included in the white oak group when the term is used as a timber classification. The live oaks, evergreen species common in the S and SW United States, are sometimes considered a separate group. The bark of some oaks has been employed in medicine, in tanning, and for dyes; that of the cork oak supplies the cork of commerce. The galls caused by certain insects are utilized commercially. The Mediterranean kermes oak ( Q. coccifera ) is host to the kermes insect, source of the world's oldest dyestuff. Acorns, the fruit of oak trees, have long been employed as a source of hog feed, tannin (chiefly from valonia, the acorn cup of the Turkish oak, Q. aegilops ), oil, and especially food. Acorns were one of the most important foods of the North American forest Native Americans; they were pulverized, leached to extract the bitter taste, and then cooked in various ways. Acorns have also been used as food in other regions where they are native. A symbol of strength, the oak has been revered for both historical and mythological associations. It was the favorite of Jove and Thor and especially sacred to the druids. St. Louis administered justice under an oak, and the Charter Oak is legendary in America. Several unrelated plants are also called oak, e.g., the Jerusalem oak (a lobe-leaved annual of the goosefoot family) and the poison oak of the sumac family (see poison ivy ). Oaks are classified in the division Magnoliophyta , class Magnoliopsida, order Fagales, family Fagaceae.

oak [OE āc]. The mighty deciduous hardwood (genus Quercus) has played a prominent role in the Celtic imagination from ancient to modern times. The English word ‘druid’ (from the Latin plural druidae) derives in part from the root dru- [oak]; Celtic words for oak, e.g. OIr. and ModIr. dair, W derwen, share the same root. The ancient geographer Strabo (1st cent. AD) reported that the important sacred grove and meeting-place of the Galatian Celts of Asia Minor, Drunemeton, was filled with oaks. In an often-cited passage from Historia Naturalis (1st cent. AD), Pliny the Elder describes a festival on the sixth day of the moon where the druids climbed an oak tree, cut a bough of mistletoe, and sacrificed two white bulls as part of a fertility rite. Elsewhere druids made their wands from only three woods: yew, oak, and apple. In Mediterranean culture the oak was sacred to both Zeus and Jupiter, some aspects of which were no doubt transferred to the worship of Gaulish Jupiter. Britons under Roman occupation worshipped a goddess of the oak tree, Daron, whose name is commemorated in a rivulet in Gwynedd. According to the pseudo-history Lebor Gabála [Book of Invasions], the sacred oak of early Ireland was that of Mugna, probably located at or near Dunmanogoe, south Co. Kildare. Sacred associations of oaks survived Christianization, so that St Brigit's monastic foundation was at Cill Dara [church of (the) oak, i.e. Kildare], and St Colum Cille favoured Doire Calgaich [Calgach's oak grove, i.e. (London-)Derry]; see also DURROW [darú, from dair magh, oak plain]. In Welsh tradition Gwydion and Math use the flower of oak with broom to fashion the beautiful Blodeuwedd. When Lleu Llaw Gyffes is about to be killed by Gronw Pebyr, his wife's lover, he escapes in eagle form onto a magic oak tree. A sacred oak tree protects the Breton city of Ys until the feckless boy Kristof removes it, allowing Ys tobe engulfed. The Arthurian figure Merlin is imprisoned in an oak tree in the Breton forest of Brocéliande by Viviane/Nimiane (the Lady of the Lake). In both British and Irish fairy lore, the oak is one of three magical woods, along with ash and thorn. OIr. and ModIr. dair; ScG darach; Manx daragh; W derwen, dâr; Corn. derowen; Bret. dervenn.

oak allusion is often made to the hardness and durability of the oak, and to the traditional use of oak timber for ships. In traditional rhymes, it may be linked and compared with other trees, as the ash and the thorn.

The Oaks is an annual flat horse race for three-year-old fillies run on Epsom Downs, over the same course as the Derby. It was first run in 1779, and is so called from the estate of the 12th Earl of Derby, owner of the first winner.
beware of an oak, it draws the stroke; avoid an ash, it counts the flash; creep under the thorn, it can save you from harm proverbial saying, late 19th century, recording traditional beliefs on where to shelter from lightning during a thunderstorm.
Oak-apple Day the anniversary of Charles II's restoration (29 May), when oak-apples or oak-leaves used to be worn in memory of his hiding in an oak after the battle of Worcester.
sport the (or one's) oak (in certain universities) shut the outer door of one's room as a sign that one does not wish to be disturbed (such doors were formerly made of oak).
when the oak is before the ash, then you will only get a splash; when the ash is before the oak, then you may expect a soak proverbial saying, mid 19th century; a traditional way of predicting whether the summer will be wet or dry on the basis of whether the oak or the ash is first to come into leaf in the spring.

See also great oaks from little acorns grow, heart of oak, little strokes fell great oaks, a reed before the wind lives on, while mighty oaks do fall.

oak / ōk/ • n. (also oak tree) a tree (genus Quercus) of the beech family that bears acorns as fruit, and typically has lobed deciduous leaves. Oaks are common in many north temperate forests and are an important source of hard and durable wood used chiefly in construction, furniture, and (formerly) shipbuilding. Its many species include the Eastern white oak (Q. alba) and Eastern black oak (Q. velutina). DERIVATIVES: oak·en / ˈōkən/ adj. oak·y adj.

oak Common name of c.600 species of the genus Quercus, which are found in temperate areas of the Northern Hemisphere and at high elevations in the tropics. Most species are hardwood trees that grow 18–30m (60–100ft) tall. Leaves are simple, often lobed, and sometimes serrated. The flowers are greenish and inconspicuous; male flowers hang in catkins. The fruit is an acorn, surrounded by a cup.

oak OE. āc (pl. ǣċ) = MLG. ēk (Du. eik), OHG. eih (G. eiche), ON. eik :- Gmc. *aiks; ulterior connections unkn.

oak
1. See QUERCUS
.
2.. (African oak) See OCHNACEAE.

oak. See limewood.

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