Canyon forest

from Wikipedia, the free encyclopedia
Gorge forest in the Bodeschlucht in the Harz Mountains

Gorge and slope mixed forests are a European type of forest . In the phytosociological system they form the association Tilio-Acerion . They are also a habitat type under the Fauna-Flora-Habitat Directive of the European Union. From a vegetation-ecological and ecological point of view, it is forests that grow on slopes so steep that the top soil and rock layer is not stable, but rather erosion takes effect, which transports rocks and fine soil from the steep upper slope areas down the slope through water, frost and root blasting so that a thicker colluvium accumulates on the lower slope , while the topsoil is characterized by very shallow soils through to adjacent rock. The species growing here have to endure this erosion on the upper slope and the partial covering on the lower slope. In Central Europe , the beech (Fagus sylvatica) is the dominant tree species ( Fagetalia ) on most soils , but it is largely absent in the ravine forest, as it obviously does not tolerate the above-mentioned location factors, and sycamore maple, sycamore elm and ash are usually the most important competitors also enforce shady lower slopes (Tilio platyphylli-Acerion pseudoplatani, sub-association Lunario Acerion pseudoplatani). When the water balance on sunny sides and in the shallower upper slope becomes more critical, Norway maple and summer linden often take over the dominance (sub-association Tilenion platyphylli).

Tree species

These are deciduous forests that are ecologically close to the beech forests , but in which the beech tree species ( Fagus sylvatica ) is receding or completely absent. Mixed ravine and hillside forests are often mixed forests rich in tree species. In terms of forestry, the tree species involved have long been referred to as " hardwoods ", today the more mundane name "ALH", other hardwoods with a long lifespan, is more common. Typical tree species are the sycamore maple ( Acer pseudoplatanus ) and Norway maple ( Acer platanoides ), the ash ( Fraxinus excelsior ), the summer linden ( Tilia platyphyllos ) and (more rarely) winter linden ( Tilia cordata ) and the sycamore elm ( Ulmus glabra ). In forestry cultivation, the beech actually thrives well here, but on the productive locations it is overpowered by the other tree species with faster youth growth in regeneration and thus out of competition.

The forest community also includes shrub communities with predominantly hazel ( Corylus avellana ), which regionally grow mainly on loose rock debris heaps.

Ecology and location

Mixed ravine and hillside forests grow on nutrient-rich (especially nitrogen-rich) and almost always base-rich, mostly well-watered, very often stony (in pedological terminology " skeletal ") soils, often colluvial soils. Maple and ash mixed forests usually grow in cool, humid locations, while summer linden forests prefer warm locations. Sometimes the forests grow up as the first forest generation after disturbances such as landslides and are then later displaced by beech-rich end forests in the succession . At suitable locations, however, they can assert themselves as a "permanent company" in the long term. The characteristic tree species benefit here from their ability to rejuvenate after disturbances from stick rash.

In terms of location and species composition, the hardwood alluvial forests and some oak-hornbeam forests are often similar in addition to the richer beech forest communities .

Forest types

According to the species composition, the mixed forests in the plant-sociological system are summarized as Tilio-Acerion, actually Tilio platyphyllis-Acerion pseudolplatani Klika 55. Species ( character types ) and separating types of the association are primarily the tree species. In addition, in the understory typical nitrogen-pointing species such as shrubs alpine currant ( Ribes alpinum ), gooseberry ( Ribes uva-crispa ), Red ( Sambucus racemosa ) and elder ( Sambucus nigra ) and the herb species Herb Robert ( Geranium robertianum ), Actaea spicata ( Actaea spicata ) and mountain knapweed ( Cyanus montanus ).

The soils in the canyon forest

The fine soil layer of the soils in the ravine forest is thin, but contains a relatively high proportion of nutrients. The ground shows a certain instability due to the mostly strong relief. The soil types are with Rendzinas , Griserden , brown earth - rankers , Regosolen , Kalkbraunerden and rarely vergleyten soil types very versatile. The humus form , if any, is gauze .

fauna

Canyon forests have a characteristic fauna: Among the butterfly species, for example, the elm hairstreak , blue-black kingfisher or the moth elm harlequin can be found. Cool damp ravine forests are home to a species-rich snail, woodlice and spider fauna.

Protection and exposure

Within the framework of the Fauna-Flora-Habitat Directive , ravine and hillside mixed forests are a priority habitat type  (9180),

Canyon forests belong to the “legally protected biotopes” according to Section 30 of the Federal Nature Conservation Act (formerly also known as “28a biotopes”) and are therefore automatically subject to strict protection. Hazards arise mainly from the entry of nutrients and pollutants from the air, changes in the water balance, excessive wild populations, intensive forestry, the promotion of a single tree species, coniferous forest afforestation and road construction.

Web links

Individual evidence

  1. ↑ National Forest Inventory: Technical terms and abbreviations published by the Federal Ministry of Food and Agriculture.
  2. ↑ Heinz Ellenberg : Vegetation of Central Europe with the Alps in an ecological, dynamic and historical perspective. 5th, heavily changed and improved edition. Ulmer, Stuttgart 1996, ISBN 3-8001-2696-6 , pp. 240-252.
  3. ↑ Erich Oberdorfer: South German Plant Societies. Part IV: Forests and bushes. Text volume (part A) and table volume (part B). 2nd edition 1992. Gustav Fischer Verlag, Jena. ISBN 3-334-60417-9 .
  4. ↑ Tilio-Acerion ravine and mixed slope forests - LRT 9180 *. State Administration Office of Saxony-Anhalt, accessed on August 22, 2016 .
  5. ↑ 9180 * Mixed ravine and slope forests (Tilio-Acerion). In: Nature Conservation and Landscape Management in Brandenburg 23 (3, 4) 2014. State Office for the Environment Brandenburg, accessed on August 22, 2016 .
  6. ↑ Landscape Information System Rheinland-Pfalz (LANIS RLP), 9180 - ravine and slope mixed forests (Tilio-Acerion) *. Rhineland-Palatinate Ministry for the Environment, Energy, Food and Forests, accessed on August 22, 2016 .
  7. ↑ Law on Nature Conservation and Landscape Management (Federal Nature Conservation Act - BNatSchG). Retrieved August 22, 2016 .
  8. ↑ Gorge and slope mixed forests (Tilio-Acerion). Habitat types of the European Natura 2000 system of protected areas . Retrieved March 12, 2017.