Brocken

Brocken Virgin Forest, Germany

At lower altitudes, the forests of Harz National Park (247 km2) were clear-felled in the past, but at the higher elevations from 900 m to the forest line at approx. 1100 m there is a small area with no signs of logging1 2. The highest top, Brocken, is at 1141 m elevation. This is a legendary gathering place of witches and demons in German mythology. The remote location, plentiful fens and boulder fields and later (from 1949 to German reunification in 1990) the location in the border zone have protected the forests1. Above 900 metres, forest is almost purely Norway spruce (Picea abies, photo right). In the natural state, European rowan (Sorbus aucuparia) would comprise about 10 % of the trees but it is now scarce due to red deer (Cervus elaphus) over-population2. At 900–1000 metres, the forest is still quite tall, at 1100 m even the tallest trees reach only a few metres. Spruce grow up to the Brocken top here and there but reach less than a metre. The Harz lacks a krummholz zone of dwarf mountain pine (Pinus mugo), which is typical for the Alps. On the forest floor, there are e.g. bilberry (Vaccinium myrtillus), wood sorrel (Oxalis acetosella), Calamagrostis villosa -grass and spruce saplings. On the top, the annual precipitation is 1800 mm and the average annual temperature 4°C 3. Persistent fogs (300 foggy days/year! 3) further increase the precipitation by 160–200 mm 4. Brocken is the windiest place in Germany3, strong southwestern winds prevailing; consequently, the precipitation on the southwestern slope is higher than on the other side of the mountain, and the forest boggy (photo below). The bedrock consists of granite3.

Boggy forest on southwest-facing slope at 950 m in 2011

Industrial emissions have led to crown thinning, soil acidification, nitrogen input and increased cover of C. villosa1. European spruce bark beetle (Ips typographus) has destroyed large areas of forest in recent years. The highest elevation forests from approx. 1050 m upwards are still in a good condition (as of 2020) but at lower elevations the destruction is total in places, particularly on the drier northeastern slopes (photo series below). Depending on the perspective, these dead forest patches can be regarded as worthless and ugly ex-forest or as a valuable biotope for many rare fungi and insects! In any case, the dead forest is full of birdsong and the beginnings of a new forest – spruce saplings – are already growing between the dead trunks. The bark beetle has always been a natural part of the Norway spruce forest ecosystem but in recent years the destruction has reached phenomenal proportions (see Introduction).

An old steam train (https://www.hsb-wr.de/ – note: very expensive!) runs from Schierke to the Brocken, where there are also a restaurant and a small hotel. It is possible to hike to Brocken from several directions.

KR

References:

  1. Sperber, G. & Thierfelder, S. (2005): Urwälder Deutschlands. BLV Verlagsgesellschaft mbH.
  2. Kison, H.-U., Harz National Park. Pers. comm. (2012)
  3. https://www.nationalpark-harz.de/en/downloads/downloads/Brocken_english_2018.pdf?m=1525686993
  4. Köhler, L. et al. (2014): Cloud water interception and element deposition differ largely between Norway spruce stands along an elevation transect in Harz Mountains, Germany. Ecohydrology Volume 8, Issue 6, pp. 1048-64.