Plaike
Plaike or Blaike , more rarely Plaicke , is a technical term from geomorphology and soil science for a form of erosion in steeply sloping mountainous terrain. The term describes a form of erosion that is particularly common on alpine pastures , which manifests itself in the sliding of large areas of meadows together with the root horizon, especially after long periods of rain. But it also occurs on other steep alpine slopes with unstable subsoil layers.
etymology
The word comes from the Middle High German blecken ("make blank, let see") and describes a place where the subsoil (the often shiny rock ) "peeps out" - an area on the mountain slope that is free of grass due to the landslide. In alpine dialects it is pronounced like "Bloak'n".
Emergence
The tearing off of the sward reveals some typical shapes that are related to the cause of the landslide . It is often due to heavy moisture penetration after heavy rainfall , but it can also be related to longer disturbances in the soil water balance or to soil erosion and other things.
A plaike can have dimensions from a few meters to around 100 meters. The parts that have slipped off often accumulate at the lower end and form wavy layers of grass or a kind of sagging .
The name Große Plaike is a 1034 m high mountain in Salzburg between Wallersee and Mondsee Flyschberge . The extensive postglacial landslide on the former edge of the glacier, which has been geologically well investigated, is now largely forested again.
Occur
Plaik erosion occurs depending on the slope of the slope , the nature of the soil, the presence of slope water and the weather. Unused alpine pastures with a slope of around 40 ° to 60 ° and altitudes in the alpine area of over 1200 meters above the closed forest are particularly affected . Starting points for plaques arise in areas without trees or bushes, when long grass freezes in the winter snow and is carried away by the sliding flow of the snow. The resulting vegetation-free areas then offer starting points for further erosion.
Plaiken have always been familiar to the alpine population, foresters, mountain farmers and attentive hikers, but their frequency has increased in recent decades. This can have various causes, for example unfavorable deforestation on steep slopes, the construction of goods roads or forest roads that are too wide , increase in heavy rain or waterlogging , changes in vegetation , geotechnical-hydrological installations, etc. In the Alps, the geophysicist and geomorphologist Adrian Scheidegger ( Vienna University of Technology) intensively dealt with these and similar phenomena.
The Hohe Blaike in the valley of the Dürnbach , a tributary of the Salzach near Neukirchen am Großvenediger , is an almost always active sliding slope . It is still a wound in the landscape today. An entire slope moves one meter down into the valley every year, despite extensive torrent barriers . In 1973, 60,000 cubic meters of rock slid into the valley.
Prevention of plaik formation
The erosion can be prevented by suitable measures, such as the balanced use of the affected alpine pastures with balanced grazing, no overuse or underuse of the grassland, constant repair of cracks, as well as the maintenance of drainage ( e.g. drainage) when there is heavy slope water. The maintenance of existing terraces also prevents the threat of erosion, which can lead to landslides and landslides .
See also
- Floor tiles
- Plaika , place names in Austria and Bavaria
literature
- Ulrich Ammer, Ulrike Pröbstl, Eva-Maria Mössmer: Erosion on alpine pastures. A contribution to current questions of soil protection. In: Forstwissenschaftliches Centralblatt. Vol. 105, 1986, ISSN 0015-8003 , pp. 48-59.
Individual evidence
- ↑ http://www.salzburg.com/wiki/index.php/Dürnbach Salzburg-Wiki "Dürnbach"
- ↑ http://forschung.uni-kassel.de/?&action=showProjekt&PNR=1617 Günter Spatz: Seed propagation of autochthonous species and their use for greening eroded areas in the Alps , research report, University of Kassel, 1999
- ↑ http://www.eduhi.at/gegenstand/geographie/data/Almen_-_Erosion.pdf Fischhuber / Glas: Almen und Erosion , "Education-Highway", Austria, 2003