American white oak
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American white oak ( Quercus alba ) |
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The White Oak ( Quercus alba ) is a plant from the genus of oak ( Quercus ) within the family of Fagaceae (Fagaceae). It is common in eastern North America . Its large distribution area as well as several distinctive individual specimens contribute to the popularity of the White Oak in North America. The American white oak is the state tree of the US states Connecticut , Illinois and Maryland . In Central Europe it is rarely found as a park tree, although it is hardy .
description
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Appearance and leaf
The American white oak is a deciduous tree . Its appearance is similar to the two European species of English oak and sessile oak . In old age the trunk reaches a diameter of 90 to 120 centimeters with a height of the tree of 25 meters. Individually standing specimens also reach far larger dimensions - heights of up to 46 meters and trunk diameters of up to 240 centimeters. While the crown is narrow and the trunk straight in the closed forest, free-standing trees form a low-set round crown with horizontal branches. In the high altitudes of the southern Appalachians , it only grows shrub-like.
The fruits show no dormancy but germinate ( hypogean ) soon after ripening in September or October. The roots grow first in autumn, and then the shoots in spring.
The root system consists of a deep tap root as well as wide-spread near-surface lateral roots. It is sensitive to flooding and soil compaction, tolerant to salt. Due to the deep-reaching roots, periods of drought can be withstood, but the taproot makes transplanting difficult in the nursery.
The bark of young twigs is reddish or red and green in color and slightly hairy, later it becomes gray and bare. A light gray bark forms on older branches and on the trunk, the color of which the name refers to. The bark is rough and divided into narrow plates, sometimes furrowed.
The brown-red, smooth winter buds are 3 to 4 millimeters in size and oval with a blunt tip.
The alternate leaves arranged on the branches are divided into a petiole and a leaf blade. The petiole is 1 to 3 inches long. The simple leaf blade is about 12 to 20 centimeters long and 9 centimeters wide, the width is greatest above the center. It has two to four leaf lobes on both sides, the ends of which are rounded. The incisions between the leaf lobes extend about one third to seven eighths into the leaf blade; the base of the spread tapers in a wedge shape. The upper side of the leaf is light green to gray-green, the underside lighter to whitish and slightly hairy when it shoots. The autumn color is purple-red to brown-violet, the dry leaves stick to the tree well into winter.
Inflorescence, flower and fruit
The American white oak is single-sexed ( monoecious ). The male, yellowish-green flowers are grouped together in loosely drooping, 5 to 10 centimeters long inflorescences that arise from buds at the base of the newly emerging branches. The female flowers are reddish and stand together in twos or threes, they are in leaf axils along the new shoot. The flowering time is in spring, around the end of March to the end of May, at the same time as the leaves shoot.
The fruits ripen in the same year. The acorns stand alone or in twos or threes, they are stalked short or not at all. The ragged fruit cup (cupula) encloses less than a third of the acorn. This has a length of about 2 centimeters and is colored light brown. The first fruits are formed between the ages of 20 and 50, and abundant fruiting occurs every four to ten years.
Chromosome number
The number of chromosomes is 2n = 24.
Occurrence
The American white oak has its ancestral and largest distribution area in eastern North America. The northern limit of the distribution is roughly the Canadian border or the Great Lakes , in the west the area extends to the prairie , almost exactly along the 95th degree of longitude . In the east the Atlantic forms the border; in the south the tree can be found with the exception of a narrow strip on the coast to the Gulf of Mexico and on the lower reaches of the Mississippi. The populated altitudes range from sea level to 1700 meters.
Different soil qualities are settled within this large area : the American white oak is often found on less nutrient-poor and drier soils , but the largest specimens grow on well-drained, nutrient-rich loam soils. Annual average temperatures of 7 ° C in the north to 21 ° C in the south are tolerated by the white oak; as annual precipitation meet 750 millimeters, but these species can also be up to 2000 millimeters endure.
The largest deposits are found in the Ohio Valley and the central Mississippi Valley at an average temperature of 13 ° C with 1,000 millimeters of annual precipitation. In the higher elevations of the northern Appalachian Mountains , where conifers dominate, this type of oak is mostly absent, as is the waterlogged lowlands.
The American white oak grows in deciduous deciduous forests throughout the distribution area. While it is rarely found above 150 meters in the north of its range, it is found in the southern Appalachians at altitudes of up to 1700 meters. In the north it also occurs in mixed forests and is associated with Quercus ellipsoidalis , Quercus prinus , the gray birch , Weymouth pine , Canadian hemlock and the sugar maple . Further south there are various red oaks and hickories as well as the sweetgum tree , dyer's oak and Quercus macrocarpa . In the south of the distribution area, various species of pine occur in association with the species on dry locations , accompanying oaks are Quercus falcata , scarlet oak and Quercus michauxii . In the forest classification of the Society of American Forresters three forest types are after the American White Oak named: White Oak - Black Oak (Quercus velutina) - Northern Red Oak ( Red Oak ) (type 52), White Oak (type 53 ) and Yellow-Poplar ( tulip tree ) - White Oak - Northern Red Oak (type 59).
ecology
Young plants can grow in partial shade, older trees do not tolerate shading as well. Seedlings that are in very shady areas can remain for many years until a gap appears in the canopy. The American white oak reacts to damage from fire with strong stick movements. The fruits are not bitter and are eaten by a wide variety of animal species, including the red-headed woodpecker , white-tailed deer , toothed quail , chipmunk , raccoon , turkey and various mice. Gray squirrels and blue jays spread by hiding fruit in the ground as a supply. The white-tailed deer also eats the leaves.
Mistletoes of the genus Phoradendron grow on the branches, while the plant species Aureolaria flava probably lives as an epiparasite in the root area . Various fungi can also be found in the root area of the American white oak, such as Russula vesca , Lactarius quietus , Cortinarius and Hymenogaster species. The wood of the oak is also colonized by fungi. Important pests are the hedgehog goatee and representatives of the genera Chrysoplenium , Sclerotina , Helotium , Corticium and Strumella , these colonize living trees. A large number of other fungi can be found on dead wood, such as Polyporus frondosus and Polyporus sulphureus as well as representatives of the genera Bulgaria and Mycena . All parts of the white oak are colonized by various insects. Species that destroy the wood are of particular economic importance. 400 different insects alone act as bile formers on the American white oak. These include species from the genera Callirhytis , Cynips , Cecidomyia , Taphrina , Dishlocaspis , Andricus and Neuroterus .
use
The wood is heavy and durable, it can be worked well and is valued accordingly. However, it is difficult to impregnate and does not absorb liquid. For this reason it is often used for barrels such as wine , rum or whiskey barrels. Since red oaks grow faster and their wood can be impregnated, they are now being planted more frequently in forestry operations.
The American white oak is occasionally planted as an ornamental or avenue tree. Only the species is on sale, not selected varieties. The use of the bark as medicine is reported by the Indians . The acorns were used as food.
Systematics
The first publication of Quercus alba carried out in 1753 by Carl Linnaeus in Species plantarum , 2, page 996th
Quercus alba belongs to the Quercus section in the subgenus Quercus within the genus Quercus . The oak species in this section are collectively called white oak. Hybrids with various other oaks from this section have been observed in nature.
Special single copies
- Legend has it that the settlers of the Colony of Connecticut hid their charter in a cave in the Charter Oak in 1687 when the royal governor tried to confiscate it.
- The Tree That Owns Itself (English for "tree that owns itself") stood in the city of Athens in the US state of Georgia . This specimen of the tree became famous for being "given back to itself as a property". In the meantime, a successor copy of Son of the Tree that Owns Itself , which was pulled from an acorn of the tree that fell in 1942, is growing at the same place . The tree is now a tourist attraction and is now over 15 meters high.
- The two Council Oaks in Arkansas marked the meeting of Robert Crittenden and Cherokee leaders , at which the Indians agreed to leave the south bank of the Arkansas River .
- The Holly Halls White Oak in Maryland is said to have stood when William Penn arrived in 1682.
- As the largest American white oak, the Wye Oak was listed in Wye Oak State Park , with a trunk circumference of over nine meters, a height of 30 m and a crown diameter of 48 m. It was destroyed by a thunderstorm on June 6, 2002.
- In the garden of the Palacio de Viana in Córdoba (Spain) there is a more than 400 year old white oak Palacio de Viana .
Evidence and further information
- H. Miller & S. Lamb: Oaks of North America. Naturegraph Publishers, 1985, ISBN 0-87961-137-5 , pp. 169ff.
- L. Moore: White Oak. - US Department of Agriculture Plant Fact Sheet , 2002. Online, accessed September 6, 2007 (PDF; 99 kB)
- Kevin C. Nixon: Fagaceae. : In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico , Volume 3 - Magnoliidae and Hamamelidae , Oxford University Press, New York and Oxford, 1997, ISBN 0-19-511246-6 : Quercus alba - online with the same text as the printed work.
- R. Rogers: White Oak. 1990 In: RM Burns & BH Honkala (eds.): Silvics of North America. US Department of Agriculture. Online, accessed September 6, 2007
- DA Tirmenstein: Quercus alba. 1991 In: Fire Effects Information System. = FEIS of the US Department of Agriculture. Online, accessed September 6, 2007
Individual evidence
- ↑ EL Little: Atlas of United States Trees , 1971. Quercus alba (PDF; 742 kB)
- ↑ FH Eyre (ed.): Forest cover types of the United States and Canada . Society of American Foresters, Washington, DC. 1980, 148 p. Quoted in Rogers (1990)
- ↑ M. Mellinger: The Ecology of the White Oak . In: Chattooga Quarterly . Chattooga Conservancy, 2000, pp. 7-8. Online ( Memento of the original from February 1, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Native American Ethobotany Database, University of Michigan Online, accessed on September 6, 2007 ( Memento of the original from September 22, 2008 in the Internet Archive ) Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Carl von Linné : Species plantarum , 2, 1753, p. 996. Scanned at botanicus.org .
- ^ Announcement Maryland Department of Natural Resources
