Oak and hornbeam forests

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Male orchid and chickweed in a chickweed oak hornbeam forest

Oak-hornbeam forests are a group of forest communities in which the common oak and sessile oak usually build an upper level of trees, below which the shade-tolerant hornbeam forms a second level. In the plant-sociological system they form the association Carpinion betuli Issl. em Oberd. (Name often abbreviated to Carpinion ) within the beech forests and beech forest-like deciduous forests (order: Fagetalia). The predominant tree species besides the eponymous sessile oak ( Quercus petraea ) or pedunculate oak ( Quercus robur ) and hornbeam ( Carpinus betulus ) are z. B. the winter linden ( Tilia cordata ), the bird cherry ( Prunus avium ), the field maple ( Acer campestre ) and sometimes also the common beech ( Fagus sylvatica ) and the common ash ( Fraxinus excelsior ). Oak-hornbeam forests rich in linden are particularly common in eastern Central Europe.

Oak and hornbeam forests only occur in Central Europe where the competitive strength of the common beech ( Fagus sylvatica ) is reduced. Otherwise, the more shade-tolerant beeches can compete with the oaks. Many, if not most of the oak and hornbeam forests were created or at least heavily promoted through forms of forest use that were common in the past, such as hat , middle or coppice forest . Many younger authors regard the oak-hornbeam forest in Central Europe as a substitute society for beech forests, i.e. no longer as climax vegetation . According to the traditional view, there are natural oak and hornbeam forests on non-bookable locations, especially in southern Germany. They are also shown in the map of the potential natural vegetation in Germany, which also provides an overview of the main areas of distribution in Germany. The actual distribution area of ​​the oak-hornbeam forests lies outside Germany in Eastern and Northeastern Europe, outside the distribution area of ​​the beech. A famous example is the Białowieża Primeval Forest in Poland.

In some cases, however, even the natural existence of the oak-hornbeam forests as a whole is called into question as a result of natural succession. For example, FWM Vera argues that oak is also used in Eastern Europe, e.g. B. in Białowieża, is not able to rejuvenate. Rather, their share of the crown layer in this forest is a relic from times when the forest was used as a Hude , and would be displaced in the long term by other, shade-tolerant species such as winter linden , elm and hornbeam . Accordingly, the oak is only competitive on pasture areas and would die out without grazing or be displaced to the most extreme locations. This argumentation represents one of the central points in the megaherbivore hypothesis , which was largely influenced by Vera , according to which in Europe it was not the pure competitive succession between the woody plants, but the influence of large herbivores on their environment that was the decisive factor for the success of species and theirs Spread. The main argument in this case is that the forest of Białowieża, if it comes very close to the original Central European vegetation, as assumed, must allow oak regeneration, otherwise the high proportion of oaks in pollen diagrams during large parts of the Holocene cannot be explained be.

Ellenberg describes it as follows: “The herb layer is so reminiscent of a Mull-Buchenwald that one is hardly surprised to find types of character with Fagion associations. To put it bluntly, the oak-linden-maple-hornbeam mixed forest of the east is a 'beech forest without beech'. "

Oak and hornbeam forests are relatively light and therefore usually have a dense and species-rich herb layer made of grasses and forest floor herbs. Common character type is z. B. the light-loving chickweed ( Stellaria holostea ). Other association characteristics are (according to Oberdorfer and Ellenberg): hornbeam ( Carpinus betulus ), bird cherry ( Prunus avium ), forest ball grass ( Dactylis polygama ), field rose ( Rosa arvensis ), strawberry cinquefoil ( Potentilla sterilis ), shadow Sedge ( Carex umbrosa ), golden buttercup ( Ranunculus auricomus ), according to Ellenberg also different-leaved fescue ( Festuca heterophylla ). Shrubs are only common in them in thinned or disturbed formations. In Western Europe in particular, twining and climbing species such as common ivy ( Hedera helix ), blackberries ( Rubus fruticosus agg.) And forest honeysuckle ( Lonicera periclymenum ) are sometimes noticeable.

A distinction must be made between:

  • Galio sylvatici-Carpinetum betuli Oberd. - Bedstraw-oak-hornbeam forest. It grows mainly on warm, dry habitats, preferably on heavy clay soils that dry out a lot in midsummer (beeches are disadvantaged here because of the winter waterlogging). The main tree species here is the sessile oak ( Quercus petraea ), but common oaks ( Quercus robur ) are not infrequently mixed in (especially in locations with varying moisture levels), sometimes even predominant. The species is the forest bedstraw ( Galium sylvaticum ).
  • Stellario holosteae-Carpinetum betuli Oberd. - Chickweed-oak-hornbeam forest. It grows on alternating damp or damp locations, often in floodplains, where it occupies somewhat drier and less flooded locations than the actual alluvial forests. The main tree species is the pedunculate oak ( Quercus robur ), typical species of the herb layer are the grove chickweed ( Stellaria nemorum ), the forest sky key ( Primula elatior ) and the golden buttercup ( Ranunculus auricomus ).

Oak and hornbeam forests grow predominantly in locations that are favorable for agriculture. That is why they have been greatly reduced today compared to their earlier distribution. In the European Union they are a protected habitat type with the Natura 2000 code 9160 under the Habitats Directive .

literature

Web links

Individual evidence

  1. ↑ Representation in Floraweb .
  2. ↑ Map of the potential natural vegetation on Floraweb
  3. ↑ FWM Vera: Grazing Ecology and Forest History . CABI Publishing, Wallingford / New York 2002, ISBN 0-85199-442-3 .