The evolution and current state of nutrient poor, acid swamp forests in the northern Black Forest region, south-west Germany

Summary

Nutrient poor, acid swamp forests account for almost 5 % of the forest area of the northern Black Forest region. Two contrary hypotheses exist in relation to the evolution of these sites. On the one hand, the waterlogged sites may have originated from a depreciatory form of utilisation (clearing, grazing, litter raking) in the past and are, therefore, a product of anthropogenic interference. On the other hand, it is possible that the swamp forests are natural paludification mires. During the period of reafforestation in the early 19th century, most of the nutrient poor, acid swamp forest sites were drained using a system of ditches. The virgin forests, probably dominated by fir (Abies alba) and pine (Pinus sylvestris and Pinus mugo agg.), were transformed into spruce (Picea abies) dominated stands in many cases. From the nature conservation perspective the nutrient poor, acid swamp forests are of particular relevance. Many endangered species with their main distribution in boreal regions depend on these sites in the northern Black Forest (e.g. capercaillie (Tetrao urogallus), three-toed woodpecker (Picoides tridactylus), and pygmy owl (Glaucidium passerinum), as well as plant species from the Oxycocco-Sphagnetea and Vaccinio Piceetea).

The following questions should be answered within the dissertation:

1.) Did the swamp forests develop as a result of natural paludification or through anthropogenic interference?
2.) How can the swamp forests best be classified and defined?
3.) What forms of land utilisation occurred in the past and how did they affect and form the current vegetation?
4.) What is the effect of ditching and how can the extent of this alteration be assessed?
5.) What is the effect of the increasing displacement of fir and pine by spruce?
6.) What relevance have swamp forests in a nature conservation context?
7.) What future forest management options are possible and how are these to be assessed?