Quarry forest

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Bruchwald in Plau am See

A quarry forest [ ˈbʁuːχ- ] (composition with the word quarry for "wetland"; regionally also Broich , Brook or Brok ) is a permanently wet, locally dammed, long-term flooded, swampy forest. This allows it to be distinguished from the temporarily flooded swamp forest and the regularly flooded alluvial forest ; both are characterized by shorter and more pronounced changes in water level.

Biotope

The Landscape Ecology and Vegetation Science grasp the concept Bruchwald relatively narrow. A "real" quarry forest is therefore characterized by the following features:

  • The locations are permanently close to the groundwater ; Fluctuations in the groundwater level above or just below the surface are usually less than one meter over the course of the year.
  • Floods mainly occur in early spring (after the snow has melted) and last for several weeks to months.
  • In the case of floods - in contrast to alluvial forests - hardly any inorganic loose sediments such as sand and silt are brought in and deposited.
  • The topsoil consists of a layer of peat made by the forest itself, at least 10 to 20 centimeters thick, made of more or less decomposed plant material.

In addition to these ideal-typical characteristics, transitions to other forest communities occur in the landscape, which are caused by deviations in certain exogenous location factors such as base and nutrient supply, proportion of mineral substrate, duration of floods, agitation of the water body, anthropogenic interventions (e.g. in the water balance) and others result in more and lead to a different vegetation composition.

Other forms of wet forests in Central Europe include alluvial forests , spring forests and wet forms of oak-hornbeam and birch-oak forests. Forests similar to quarry forests, which, for example, do not meet the criterion of the corresponding peat thickness, are often classified as “other swamp forests” in nature conservation . This is true even if both the dominant tree species and the plant species of the herb layer (see below) resemble those of "real" swamp forests.

An undisturbed quarry forest is understood as a natural, azonal forest community that represents a stable climax stage of the vegetation under these site conditions. All societies of real swamp forests are to be understood ecologically as bogs characterized by tree vegetation . Depending on the hydrology of the respective bog type and the resulting base and nutrient supply, it is a matter of forms of minerotrophic fens or - hydrologically sometimes disturbed - mainly rain-fed transitional and raised bogs . The latter in particular are also called bog forests and are characterized by moderately to strongly acidic soils. Some authors use the terms (sour) quarry forest and peat forest synonymously, others differentiate between primary quarry forest and secondary peat forest on drained Poor bog locations.

The former Elchniederung district is a largely untouched swamp forest area . The Großer Moosbruch alone covered 125 square kilometers and was considered the largest closed raised bog in Germany.

Quarry forest types in Central Europe

Alder fragments

Schwaanhavel
Erlenbruchwald near Uhyst in Teichlausitz

Alder forests often grow on fen soils that are better supplied with nutrients, with a focus on planar to submontane regions. Name factor is the dominant characteristic species of alder ( Alnus glutinosa ). Typical of the trees is the trunk foot with stilt roots; Thanks to its adventitious roots , the black alder can cope with heavy moisture and fluctuating water levels comparatively better than many other tree species. The undergrowth (herb layer) is rich in sedge (for example with the roller sedge , Carex elongata or the swamp sedge , Carex acutiformis ); free water areas are often formed in which the small duckweed ( Lemna minor ) floats. Other characteristic plant species of this type of biotope are the bitter-sweet nightshade ( Solanum dulcamara ) and the snake root ( Calla palustris ). On tall herb settle here among other things, water hemlock ( Cicuta virosa ), Eupatorium ( Eupatorium cannabinum ), Shore Wolfstrapp ( Lycopus europaeus ), Common Loosestrife ( Lysimachia vulgaris ), purple loosestrife ( Lythrum salicaria ), reed Buttercup ( Ranunculus lingua ) and great water dock ( Rumex hydrolapathum ).

In terms of plant sociology, the alder forest association (Alnion glutinosae) is differentiated into the following associations, depending on the hydrological and edaphic site conditions and the plant geography in Central Europe:

  • Moorseggen-Erlenbruch, Carici laevigatae-Alnetum (EU-Atlantic)
  • Walzenseggen-Erlenbruch, Carici elongatae-Alnetum (subatlantic-subcontinental)
  • Alder forest rich in peat moss, Sphagno-Alnetum (in the highlands of the low mountain range )

According to the nutrient supply, further sub-associations can be distinguished; in the most common and most widespread Walzenseggen-Erlenbruch forest, for example, the nutrient-rich iris-alder-break, the typical alder-break with swamp sedges or swamp fern as well as the mesotraphent peat birch-alder break. After drainage measures, depending on the previous sub-community, degeneration stages rich in blackberries, ferns or nettles can be found, which, after the mineralization of the peat body, represent wet to swamp forests. The so-called foam herb-alder break or alder spring forest (including spleen herbs and bitter foam herb ) forms a transition society to the alder-ash floodplain forests from the Alno-Ulmion (hardwood floodplain) and is often attributed to them.

The plant-sociological association Salicion cinereae (willow bushes and swamp forests), which grows on wet moor, gleyas or fens and is determined by shrub willows such as the eponymous gray willow and the ear willow , is usually a preliminary stage of (alder) scrub forests in the succession sequence . Other characteristics of various associations of this association are, for example, the ash , bush-birch , laurel-willow and the gale .

Birch, pine and spruce fragments

Birch forest in the gable moor

Birch forests grow on relatively nutrient-poor, acidic peat soils on the edge of raised and intermediate moors and on dystrophic bodies of water. Secondarily, degraded, i.e. drained, raised bog sites can also be taken over by wet birch or pine forests (bog forests ). On locations that are very poor in acid and nutrients (central raised bog areas), only bog woods with limited vigor develop. If the locations are better supplied with nutrients, they take on the character of a forest. The herb layer is often characterized by the dominance of peat moss ( Sphagnum ), with partially drained forms by dwarf shrubs ( Vaccinium ), pipe grass ( Molinia caerulea ) or bracken ( Pteridium aquilinum ).

Downy birches and Scots pines have a competitive advantage over black alder in particular on peat soils whose base supply falls below a certain minimum. Whether moor birch, Scots pine or also spruce prevail as the main tree species depends on the large climatic situation: In the Atlantic-subatlantic north-west of Central Europe, the downy birch comes to the fore, in the subcontinental to continental area alongside this also the pine, in mountains and in Northeastern Europe the spruce. Corresponding intermediate forms between birch and alder quarry forests occur at transition locations with moderate alkaline supply.

In terms of plant sociology, the following societies are distinguished within the Association of Birch and Broken Pine Forests (Betulion pubescentis):

  • Birch quarry forest, Betuletum pubescentis: Atlantic-subatlantic widespread, light bog birch forest on nutrient-poor peat soils on the edge of raised bogs and dystrophic waters in the wet-oligotrophic area.
  • Bogberry-Scots pine-quarry forest, Vaccinio uliginosi-Pinetum sylvestris: Subatlantic to subcontinental occurring, natural, light bog forests of bog forest pines ( Pinus sylvestris fo. Turfosa ) and bog birches; widespread in the northwestern German lowlands.
  • Quarry pine forest, Ledo-Pinetum sylvestris: Nordic-continental society on the edges of the moorland (in Germany east of the Elbe ) with the differential species swamp porst ( Ledum palustre ).
  • Carpathian birch quarry, Betuletum carpaticae: light birch bog forest with the differential species Carpathian birch ( Betula pubescens ssp. Carpatica ) on the edges of swelling high and intermediate moors in the montane locations of the low mountain ranges, for example in the Ebbegebirge , in the Spessart , Solling and Kaufungen forest .

In addition, broken spruce forests are classified in the class of boreal-subalpine coniferous forests (Vaccinio-Piceetea) and, among other things, the associations

  • Spruce-moor forest, Vaccinio-Piceetum (in the montane to subalpine altitude range of the Alps and in low mountain ranges) and
  • Mountain pine moor forest, Vaccinio uliginosi-Pinetum rotundatae ("Spirkenmoore" in the Alpine foothills and in various low mountain ranges).

In the case of the former, the spruce ( Picea abies ) acts as a differential species, in the case of the latter, the Moor Spirke ( Pinus × rotundata or Pinus mugo ssp. Uncinata ) as a character species.

Quarry and bog forests

Bog forests in North America

Bog forest in Minnesota

In the boreal zone of North America, bog forests with black spruce ( Picea mariana ) and East American larch ( Larix laricina ) as well as the western arborvitae ( Thuja occidentalis ) have developed. In the south and southeast of the United States there are swamp moors and swamp forests, which are composed of the bald cypress ( Taxodium distichum ) and the tupelo tree ( Nyssa aquatica ). The best-known example is the Everglades in Florida. These are inundation bogs in river valleys and in coastal areas or swamp bogs fed by inflow water.

Peat forests in Southeast Asia

Indonesia's forests grew predominantly on thick peat beds . Here, especially on Sumatra and Borneo , are the largest peat forests in the world, the trees of which can be up to 50 meters high. These moors cover a total of around 170,000 km², almost half the area of ​​Germany. There are up to 120 tree species on one hectare. The high variety of pitcher plants is also characteristic . The causes of the peat formation are the very slight slope of the terrain and the large masses of water that the rivers bring from the interior to the coastal plains. In the rainy season, the water accumulates and floods the forest floor for months. The peat forests in Indonesia and Malaysia are being destroyed to a terrifying extent for the establishment of palm oil plantations. Often they are lit for this purpose. In the summer of 2015, the forest fires reached extreme proportions.

Danger

Quarry forests in Europe are particularly endangered by drainage and subsequent agricultural or forestry use, such as reforestation with non-biotope tree species (especially hybrid poplars ). Eutrophication is to be seen as a further source of danger, especially of the nutrient-poor sub-societies, as here vigorous, nitrophilic perennials displace the less competitive bog plants.

Others

Elsbruch in Saarmund

Near-natural sour swamp forests (primary bog forests) are listed as "priority habitat types" in Appendix I of the EU Fauna-Flora-Habitat Directive (Natura 2000 Code 91D0). Specially protected areas must be set up for such occurrences.

In Brandenburg in particular , the still preserved alder fragments are also known as Elsbruch . Els is the Low German expression for alder.

See also

literature

  • Heinz Ellenberg : Vegetation of Central Europe with the Alps from an ecological point of view. 4th, improved edition. Ulmer, Stuttgart 1986, ISBN 3-8001-3430-6 .
  • Richard Pott: The plant communities in Germany. UTB for science, Ulmer Verlag, Stuttgart 1992, ISBN 3-8252-8067-5 .
  • Michael Succow , Lebrecht Jeschke: Moors in the landscape: origin, household, living world, distribution, use and preservation of moors. Verlag Harry Deutsch, Thun / Frankfurt am Main 1990, ISBN 3-87144-954-7 .

Web links

Individual evidence

  1. ↑ Olaf von Drachenfels (edit.): Mapping key for biotope types in Lower Saxony. Status September 1994. - Nature conservation and landscape management in Lower Saxony, A / 4, ISBN 3-922321-69-0 , pp. 1–192.
  2. ↑ The primeval landscape
  3. ↑ LRT 91D0 * - Bog forests (PDF). Federal Agency for Nature Conservation .