Quercus robur
English Oak (Quercus robur)
The pedunculate oak (Quercus robur, Syn: Quercus pedunculata ), also called summer oak or German oak is a deciduous tree species in the genus of oaks (Quercus ) in the beech family ( Fagaceae ). To emphasize their belonging to the genus of oaks, the hyphen notation common oak is common in botany. The oak is " Tree of the Year " in 1989.
Dissemination
The oak is the most widespread in Central Europe of oak. It occurs in almost all of Europe. They only lack in the southern Iberian Peninsula, Sicily, in southern Greece, northern Scandinavia and northern Russia. In contrast to the sessile oak reaches their range much further to the East, as they can withstand continental climate much better. The spread of English oak ranges in the Bavarian Alps up to 1000 m.
At best, the oak developed on nutrient-rich, deep loam and clay soils. It can due to their good adaptability but also alternating wet to colonize wet pseudogley and Gleyböden. The light oak needy displaced in Central Europe on normal locations of the shadow -tolerant, highly competitive European beech. It is therefore only to special locations forming stands, that is, in the periodically flooded Hartholzauwäldern of the large currents on strict clay soil in oak-hornbeam forests and on poor, dry sandy soils in oak-birch forests and oak-pine forests. To the east of the range of the beech does not happen anymore because of the late frost risk, so there together with hornbeam, Scots pine and silver birch oak trees form the natural forest community.
Many oak forests in Central Europe are anthropogenic. There are grown by means forests, as the oak, the periodic on - the - floor - setting tolerate better than the red beech. Even the oak trees have been funded historically been targeted because of its valuable timber and its useful as fodder crops.
Geologically oaks are already detected from the Tertiary. They are found fossil already 12 million years ago, about in sediments of the Hambach opencast mine in the Rhineland.
Diseases and Pests
- Mildew
- Leaf spot ( Septoria spp.)
- Anthracnose ( Apiognomonia quercina )
- Gall midges ( Macrodiplosis volvens KFFR. )
- Phytophthora spp.
- Honey fungus ( Armillaria spp.)
- Spindled Rübling ( Collybia fusipes )
- Two Punk Tiger oak borer ( Agrilus biguttatus )
Description
The oak is a 20-40 meter high tree with a trunk diameter of up to three meters. Their maximum age is 500 to 1000 years, in exceptional cases up to 1400 years. Its bark is smooth and pale gray - green shining in youth, later a thick, deeply longitudinally fissured, gray -brown bark is formed. The buds are blunt, ovoid and sit heaped at the growing tips. The alternate, leathery leaves are petiolate only briefly and are 10 to 15 inches long. They are deep green on the upper side glossy, lighter on the underside and lobulated in five to six bays. The oak is monoecious getrenntgeschlechtig. The ability to form keimbare acorns, it reaches about the age of 60 years. It flowers from April to May and the acorns ripen from September to October. The acorns sitting at third to fifth at 1.5 to 4 centimeters long stems (hence the name pedunculate oak ) and are up to 3.5 inches long. The acorns are different animals as food and disseminated by them. Especially the jay makes by investing food depots for the distribution of the pedunculate oak ( Hähersaaten ). The oak is a strong taproot; thanks to its roots, it is extremely storm-proof. You can also open up with their roots heavily compacted soils to achieve low-lying groundwater.
Differences to the sessile oak
The pedunculate oak and sessile oak are very similar. Many taxonomists and geneticists see in the sessile oak only one location breed of English oak. In the distribution and morphology, there are some differences, however: The English oak is found mainly in the lowlands and the alluvial forests. Their fruit sit at a few on long stalks. The leaves are short-stalked. The leaf base is cordate and auriculate. In the middle of the leaves Spreitenbereich the lateral nerves forming in the bays. The buds of chestnut oak are slightly slimmer than the English oak.
Use
The oak is a ringporiger heartwood tree. The yellowish-white sapwood is configured to be relatively narrow, the heartwood is light to dark brown color. The average bulk density is 0.65 ( 0.39 to 0.93 ) grams per cubic centimeter. Oak wood is hard, tough, very durable and easy to edit. It is very versatile: as a timber, in hydraulic engineering, railway sleepers and poles and masts. For indoor use, it is suitable as flooring, stairs and as a furniture wood. High quality oak wood is processed as a veneer or used for Fassbau. The oak also provides an excellent firewood.
Previously, the use of acorns was as important as the use of wood as a feed for pigs and deer. The inedible by bitter substances for humans acorns are highly nutritious and contain up to 38 % starch. The pigs were driven into the oak woods and fattened in good seed years with the acorns. From this time the award comes on the oaks of the best ham grows. For cattle and horses acorns and oak leaves are harmful due to the high tannin content.
Another was the use of the bark as a tanner. For this, the oak was as coppice, so-called Lohhecken, farmed, harvested every 15 to 20 years, ringed the tribes and peeled the bark. The dried bark has a tannic acid 8-20 %.
Medicinal plant
As a drug, are the dried bark of young branches and coppice. The pharmaceutical drug name is Quercus cortex (Latin for oak bark; old: Cortex Quercus ).
The bark contains usually 10% ( to 20 %) tannins, which is primarily Catechingerbstoffe ( oligomeric proanthocyanidins ) is. The European Pharmacopoeia (Ph. Eur ) calculates the catechins as pyrogallol and requires a minimum level of 3 %. In addition, ellagitannins and complex tannins, for example, come Flavanoellagitannine and Quercitol and triterpenes ago. In the leaves and green fruits are still in tannin present in a content of up to 15%.
Externally come full baths or envelopes with preparations of oak bark for use, especially in inflammatory skin disorders (not for weeping eczema / extensive skin damage). Local Applications of oak bark are mild inflammation in the mouth and throat as well as in the genital and anal area. Internally oak bark is applied to non-specific, acute diarrheal diseases, such as tea.
Cultivated forms
The following is a selection of breeding forms of English oak:
- Gold oak (Q. robur ' Concordia '): 1843 originated in Belgium; the foliation is golden yellow, yellowish green in summer the foliage. This form is rare and can be planted about 13 feet high.
- Pyramids oak ( Q. robur 'Fastigiata' ): It grows like a pyramid poplar very tightly maintained and very narrow. The tree can reach 20 to 25 meters high and 1 meter diameter trunk. Commonly seen in larger parks and formal gardens. The most outstanding representative is the Beautiful oak at Harreshausen.
- Q. robur ' filicifolia ': The foliage is that of, Pectinata ' similar, but the lobes are very slim and have a ruffled edge.
- Q. robur ' Pectinata ': It has deeply cut leaves; the lobes are just not curled and.