Quercus rubra
Red oak (Quercus rubra)
Red oak (Quercus rubra), also known as American Spitz oak, is a native to North America deciduous tree species from the genus of oaks. It is the official state tree of the U.S. state of New Jersey.
Description
The red oak is usually 20 to 25 meters, but also sometimes to 35 meters high and forms a round tree crown. It can be up to 400 years old, while reach a trunk diameter of up to two meters. The bark is gray and smooth. Later, a dünnschuppige bark is formed. Red oak has in youth a taproot, and later a heart root system.
Its leaves are up to 23 cm long and have each page half four to five lobes, which are separated by up to five centimeters deep bays. The ends of the lobes are tapered. The leaves sit on a 2 cm, sometimes up to five cm long yellowish stem. The fresh leaves appear yellow in the first three weeks; then the leaves are green and strong bright red to orange in autumn; on older trees partly yellow to brown.
The male flowers hang down loosely and are yellowish - green. The female flowers are solitary or in pairs. The flowering time is in Central Europe in May. The acorns mature in the second year. They are broad, egg-shaped and about 2 × 2 cm in size and are available in flat, surrounding cups. The calyx cup sits at a thick about 1 cm long stem.
The red oak is extremely fast-growing. In young trees sometimes Jahrestriebe be observed of 2.5 m length. The shoot growth occurs in two periods in mid-May to early June and late July to early August. In free-standing red oak flowers already in the relatively young age of 25 to 30 years.
System
Depending on the author, two varieties Quercus rubra are in the red oak var borealis ( F.Michx. ) Farw. ( Basionym: . Quercus borealis F.Michx ) and Quercus rubra rubra var distinguished. Trees from the southern area of distribution have more drooping leaves with deep bays, as well as left and right each about 6 lobes; this partly as a separate variety Quercus rubra var maxima Marshall viewed and are - in contrast to the far north to Canada in domestic type - apparently somewhat susceptible to frost.
Cultivated forms
- 'Aurea ': This form bears intensely golden yellow leaves, which, however, in the course of the summer nachgrünen something.
Distribution and location
The home of the Red Oak is located in eastern North America, ranging there from Canada ( southern Ontario) south in the United States to Texas, Georgia, Missouri, Arkansas and Oklahoma. In the Appalachians they come up before at altitudes of over 1600 meters.
In Central Europe, the red oak since the beginning of the 18th century - often planted as park and street tree - because of their attractive leaf shape and its pretty autumn colors. The date of initial deployment will be called in 1691 or 1724. In urban climate it is as successful as the English oak. You, however, not suitable as a street tree or place, because their roots lift asphalt paving slabs on compacted soils.
In many parts of Europe it is also used for forestry. Beginning of the 20th century, the red oak was planted as a replacement for the native oak species that were decimated by feeding damage. This partly arose selbstvermehrende Roteichenbestände, through the dissemination by Jay, the red oak colonize other areas. Compared to the native species of oak, the red oak is more resistant to pests, shadow and sound growth stronger. It is planted in pure stands or in mixture with beech. The red oak provides its best growth performance in well - served bases, deep soils, but can also grow on nutrient- poor sandy soils. She avoids waterlogged, flooded or extremely flat enigmatic locations. On chalky and dry sites change the red oak is preferred infested with root rot, which can lead to increased losses, defoliation and root fractures.
Verwildernde stocks of red oak in Central Europe, which show a tendency to naturalization, there are acidic, shallow soils, especially rocky sites. It forms here a competition with domestic sessile oak (Quercus petraea ), while they are on better soils can not relate to the common beech (Fagus sylvatica). Are striking, for example, feral red oaks in the Elbe Sandstone Mountains, where it grows on rocks far a forest cultivation and is safe naturalized.
Terms and Ecology
Red oak is a heartwood tree with thin bright sapwood and reddish brown core. Its wood has an average bulk density of 0.65 g / cm ³. The wood of the red oak can be used similar to the wood of the native pedunculate oak and sessile oak, but is overall less valuable. So the red oak veneers are irregular structured. The coarse-pored wood has very wide lumen vessels. These remain unverthyllt so that red oak is not suitable for the manufacture of barrel after the heartwood.
The Northern Red Oak is planted as a fire bolt in many coniferous forests, as their acidic and poorly decomposed leaves hinder further growing and thus a possible fire can be braked.
The red oak is one of the assertive foreign plant species ( neophytes ); the release should not be undertaken without hesitation and a large area.