Birch-oak forest

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Birch-oak forest near Zwiesel

A birch-oak forest or oak-birch forest is a western and central European plant community in which the silver birch ( Betula pendula ) and the oak ( Quercus robur ) predominate. Plant- sociological classification: Association Betulo (pendulae) -Quercetum roboris , Association Quercion roboris , order Quercetalia roboris (-petraeae) .

Emergence

Birch-oak forests grow on dry to fresh and very nutrient-poor soils such as pure quartz sand or sandstone with the soil type Podzol , where the living conditions for the common beech are not sufficient, while the less demanding tree species common oak and sand birch can still thrive. The emergence of the birch-oak forests is likely to have been promoted by grazing and forest management of oak and beech forests on relatively nutrient-poor soils. Most authors now assume that natural birch-oak forests are very rare as climax vegetation and only occur in small areas. Most of the stands of this type of forest are former beech or beech-oak forests that have been degraded due to previous use. The beech-oak forest forms a transition form between birch-oak forest and red beech forest .

description

In stands of this type of forest, the common oak ( Quercus robur ) predominates in the tree layer. Due to the nutrient-poor location, the oaks always remain deficient. Contrary to the impression given by the name, birch trees are steady, but usually only mixed in sporadically. Birch-rich stands are usually young succession stages . The forest as a whole is quite light. This is not only due to the fact that birches and oaks let a lot of light through their less dense canopy, but also because of the low supply of nutrients, no dense shrubbery and herbaceous layer can develop.

The birch-oak forest is relatively poor in species. In addition to birches and oaks, trembling aspen , bracken , bilberry , lingonberry , heather , mountain ash , buckthorn , broom and sometimes the lily of the valley thrive here . (Some authors separate the formation, which is rich in dwarf shrubs, as an independent plant community, cranberry-oak forest, Vaccinio vitis idae-Quercetum.) Where the winter is mild enough, the holly also grows .

Birch-oak forest is typically light

distribution

Birch-oak forests are the zonal vegetation from the Portuguese to the Danish coast. They form the potential natural vegetation in the Dutch-northwest German-Jutland geest . The pine is penetrating more and more to the east. For example, there are pine-rich birch-oak forests in the Baruther glacial valley and in the Prignitz area . In the extrazonal islands of the low mountain range there are also small-scale birch-oak forests. Their main occurrence in Germany is in the nutrient-poor areas of the Lower Rhine lowlands and the Westphalian Bight, such as in the Emsland , in the Minden forest and the Wentrup mountains near Greven .

Economic importance and risk

The forestry benefit of the birch-oak forest is low, which is why many stands have been replaced by pine forests or converted into arable land. Today, however, many stands are also subject to a natural succession to the beech forest, which is to be addressed as recovery after use-related degradation. According to the Red List of Plant Associations in Germany, it is considered to be endangered. In North Rhine-Westphalia, the main distribution area of ​​this type of forest alongside Lower Saxony, the same degree of risk applies today.

See also

literature

  • Richard Pott: Biotope Types . Verlag Eugen Ulmer, Stuttgart, 1996, ISBN 3-8001-3484-5
  • Otti Wilmanns: Ecological Plant Sociology . 3rd edition, UTB Quelle & Meyer, Heidelberg, 1984, ISBN 3-494-02027-2

Individual evidence

  1. Overview at FloraWeb
  2. Map of the potential natural vegetation in Germany at FloraWeb