What influence do forest fires have on the stability of rocks? And will being in the mountains become more dangerous in the future if boulders tumble unbraked from trees? These are the central questions of the "Firerisk" research project, which has now begun its work. The first site inspection took place on 4 April 2025. A team from TU Bergakademie Freiberg led by Professor Christoph Butscher and Dr Jörn Wichert, together with Charles University in Prague and the Dresden University of Applied Sciences (HTW Dresden), is investigating a field that has hardly been researched to date and is becoming increasingly important due to climate change and increasing forest fires.
Since the major fire in Saxon and Bohemian Switzerland in 2022, the Freiberg geology team has been investigating the stability of rocks and the increased risk to people in the mountains. The risk is particularly high in areas heavily used by tourists, such as the Elbe Sandstone Mountains. Previous research work has pointed this out: the TU Bergakademie Freiberg and the TU Dresden, for example, investigated the influence of fires on the stability of sandstone and granite. Two other projects focussed on the problem of mass movements in mountains. A project with the Charles University in Prague in the Saxon-Bohemian Elbe Sandstone Mountains investigated the internal structure of various rocks, including the tower of the Rathen rock theatre. Together with the HTW Dresden, types of mass movements, threats to infrastructure and the stability of slopes were analysed in a large-scale project in the Caucasus. The resulting data was used to set up a geoinformation system (GIS) and develop corresponding safety concepts.
An essential part of "Firerisk" is the investigation of the phenomenon of unconsolidated sandstone rocks found in the Elbe Sandstone Mountains. Put simply, these are rocks with a solid sandstone shell and loose sand inside. So far, little is known about the structure of these rocks and their spatial distribution. In order to gain more knowledge about this, non-destructive methods that have already been tested, such as geophysical measurements and methods of analysing aerial images, are to be further developed.
In order to determine the material properties of the sandstone before and after fires, large-scale fire tests will be carried out at different temperatures and durations. The results are crucial for the planned geotechnical fire models, which the Czech and German scientists will use to calculate the stability and behaviour of rocks and debris corridors in different fire scenarios.
Models for national park administration and population
All spatial data will be incorporated into a bilingual GIS, which will also be made available to the general public as a WebGIS via the project website.
The topic of forest fires also raises the question of concepts for the forest stand from a nature conservation perspective. For this reason, the national park administrations of Saxon and Bohemian Switzerland are also acting as partners in the "Firerisk" project.
In addition, the city of Děčín will set up a "rock group" that deals with the potential risk of rockfalls or landslides in its area of responsibility. The project will also be presented at Czech and German schools. Practical investigations and small school projects will enable pupils to learn about scientific relationships. The aim is to introduce young people to scientific work and awaken their interest in STEM subjects.
