Burnt soil and the consequences
The Brandenburg University of Technology Cottbus - Senftenberg, Research Centre for Landscape Development and Mining Landscapes (FZLB) is investigating the effects of forest fires on the soil.
In addition to the soil characterisation of the site, the material yields are also considered. Here are the first results:
Humus
Soil analyses show that large parts of the humus layer were destroyed by the forest fires near Jüterbog and Treuenbrietzen, with average losses of around 30 tonnes of carbon per hectare.
Fire impact depth
The effects of the forest fires are concentrated in the uppermost centimetres of the investigated soils; below a soil depth of 5 cm, the effects are only slightly pronounced.
Soil chemistry
The ash left behind after the burning of humus and plant residues changes the chemical properties of the soil, in some cases significantly, which can be seen, for example, in increased pH values in the topsoil.
Substance discharges
Laboratory experiments have shown that the burning of humus and plant residues releases large quantities of nutrients, which are washed out of the topsoil with the seepage water within a few months and may therefore be lost to the regrowing plants.
Soil animals
Both the fire itself and the subsequent management of the forest fire area influence the occurrence of insects and spiders, whereby the removal of burnt trees tends to have a negative effect on species diversity.
The picture gallery shows impressions of the investigations:
Soil analyses on the forest fire areas: Soil profile Y2 in Jüterbog. (Photo: Werner Gerwin)
Comparison of a reference area with a burnt area: the humus layer is destroyed. (Photo: Werner Gerwin)
Sampling of the humus layer on the unburnt reference area Z. (Photo: Werner Gerwin)
Taking soil samples on a ploughed forest fire area: Site F (Photo: Werner Gerwin).
Laboratory experiment with controlled burning of the humus layer and analysis of the leachate. (Photo: Frank Repmann)