Mittelsteighütte

Primeval Forest Mittelsteighütte, Bavarian Forest National Park, Germany

The grove “Mittelsteighütte” in the Bavarian forest probably is the epitome of a “primeval forest” in Germany as it bears this epithet in its title and is well known in Germany under this name1. Actually, the example of “Mittelsteighütte” shows how difficult and ambiguous the term “primeval forest” can be.

The area, approximately 38 hectares, is located on the south-west slopes of the mountain “Großer Falkenstein” at elevations between 705 and 800 metres above sea level. Thus, “Mittelsteighütte” is the only one of several remnants of “virgin forest” in the Bavarian forest at lower elevations. As early as 1761, the area was declared a protected forest (“Bannwald”) for military reasons (protection of the Bavarian border). In 1914, the area was declared a “preservation district” (“Schonbezirk”) and then in 1939 dedicated as a nature reserve before it eventually became part of the Bavarian Forest National Park. The mean annual temperature lies between 5.5 and 6.5°C, the annual precipitation ranges from 1100 to 1300 mm. The forest consists primarily of European beech (Fagus sylvatica), Silver fir (Abies alba) and Norway spruce (Picea abies), intermixed with scattered sycamore maple (Acer pseudoplatanus). A few wych elms (Ulmus glabra), large-leaf limes (Tilia platyphyllos) and yew trees (Taxus baccata) also grow sporadically in the area2.

“Mittelsteighütte” is located directly at the edge of the small village Zwieslerwaldhaus. Two marked hiking trails lead through the area. As the reserve is part of the strictly protected core zone of the National Park, hikers must not leave the established trails. In the north-eastern part, one will find an approximately 400-m² forest-meadow, remnant of a former goat pasture. Numerous towering trees exceeding 50 meters in height and deadwood amounting to more than 150 m³ per hectare (photo below) give the area a very “primeval forest” impression.

Larvae of primeval forest relict beetle Ceruchus chrysomelinus develop in this like thick dead fir trunks

However, looking closer, “Mittelsteighütte” is not at all an “untouched” forest. In the long period of protection since 1761 several human interventions have occurred: In the period up to 1914, only a few single trees were extracted for fuel in the adjacent glassworks2. Between 1930 and 1935, downed trees totalling 3.985 m³ were extracted from the forest after windthrow. This amount of wood amounts to a complete thinning of the area. The responsible forest office in Zwiesel took the following position: “The thought of letting all this valuable wood rot is utopian”3. This situation resembles that in the “Primeval forest Rothwald” (Austria).

Furthermore, until about 2010, old and decaying trees along the trails in the area were felled for safety reasons. Although the trees were not removed, stumps and logs are still visible. There are also indirect human influences on the forest like increased browsing by ungulates: In the whole Falkenstein area, browsing on Silver fir is heavy so only little regeneration of silver fir can be found in “Mittelsteigütte”. Consequently a dense layer of pole-sized beech characterises the area, which, similar to Žofínský-prales, is increasingly developing into a pure beech forest.

With so many human influences, is the “Primeval forest Mittelsteighütte” still a primeval forest? We discussed this question critically when creating this website. The fact is that this forest is not untouched by humans and that other remnants of “primeval forest” in the Bavarian forest, like “Höllbachgspreng” or “Rachelseewand”, show less human influence. Nevertheless, a whole range of species are found in “Mittelsteighütte” which are considered by scientists as indicators of primeval forest conditions. Here are just a few examples of these species, which are extremely rare or already extinct in the rest of Germany:

Phellinus pouzarii is a fungus that grows on old deadwood of Silver fir and Nordmann fir (Abies nordmanniana); fewer than ten sites of this species are known worldwide. These sites are located in untouched and often large areas of primeval forest like Biogradska Gora National Park (Montenegro) or the “Primeval forest Rothwald”. The reserve “Mittelsteighütte” is the only location in Germany where this extremely rare fungus associated with primeval forests is found4.

The stag beetle Ceruchus chrysomelinus, a red-list 1 Species (= threatened with extinction), belongs to a group of saproxylic beetles that are named “Urwaldrelikt-Species”5. Although this beetle is known from a few other forest areas in Germany, it has a particularly large population in “Mittelsteighütte”, which is the focus of its occurrence in the whole range of the Bavarian forest.

Further examples of species that only occur under primeval forest conditions and that are found in “Mittelsteighütte” are the deadwood fungi Antrodiella citrinella4 and Climacodon septentrionalis, as well as the flat bug Aradus betulae6.

After 2010 Antrodiella citrinella and Ceruchus chrysomelinus have been observed to have dispersed from “Mittelsteighütte” into the wider area of the National Park. This fact shows that such old forest reserves are more than just “forest museums”: In the first instance, they can constitute a refuge for rare species associated with primeval forests. If then certain habitats (e.g. deadwood) in the adjacent forests become more abundant, such reserves could become a source for an enhanced local population of these species7.

Is “Mittelsteighütte” a primeval forest? This question must remain open for the time being: The area is not a primeval forest in the sense of an untouched forest. At least along the trails remains of human interventions are still visible even today. However, despite such interventions “Mittelsteighütte” has a nationwide importance in Germany for several species that can only occur under primeval forest-like conditions.

TM

References:

  1. See e.g.  https://de.wikipedia.org/wiki/Urwaldgebiet_Mittelsteighütte
  2. Löfflmann, Hartwig 1988: Urwaldbestand Mittelsteighütte im Forstamt Zwiesel; Waldwachstumskundliche Beobachtungsfläche “ZWI 137”; Ertragskundliche Zustandsaufnahme und Strukturanalyse (Diplomarbeit an der LMU München)
  3. Englmaier, Karl-Heinz 2017: Geschichte des Nationalparks Bayerischer Wald und seiner Nationalparkregion (Nationalparkverwaltung Bayerischer Wald)
  4. Moning, Christoph et al. 2009: Ökologische Schlüsselwerte in Bergmischwäldern als Grundlage für eine nachhaltige Forstwirtschaft (Wissenschaftliche Reihe Nationalpark Bayerischer Wald – Heft 19)
  5. Müller, Jörg et al 2005: Urwaldrelikt-Arten – Xylobionte Käfer als Indikatoren für Strukturqualität und Habitattradition (waldoekologie online Heft 2)
  6. Gossner et al 2017: Wanzenfunde anlässlich des 42. Treffens der „Arbeitsgruppe Mitteleuropäischer Heteropterologen“ im Zwieseler Winkel, Nationalpark Bayerischer Wald, Beiträge zur bayerischen Entomofaunistik 17:19–42, Bamberg (2017), ISSN 1430-015X
  7. Müller, Jörg & Bässler, Claus 2009: Importance of natural disturbance for recovery of the rare polypore Antrodiella citrinella Niemelä & Ryvarden (Fungal Biology 114)