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Graphic: Klara MrakClimate change causes rising temperatures, precipitation deficits, and increasingly frequent extreme weather events. These stress factors compromise the vitality of forest stands and promote large-scale bark beetle infestations, particularly in young spruce monocultures, resulting in widespread tree dieback across Germany. The common practice of removing deadwood from such sites causes substantial nutrient losses and can impede natural forest regeneration. At the same time, societal and political expectations regarding forest ecosystem services are rising. The PoToMa project aims to compare different strategies of deadwood management in commercial spruce forests at mid-elevation sites.
The project's central question is whether the retention of standing or lying deadwood creates favorable microsites for seed germination and the establishment of pioneer and target tree species, and how deadwood influences the ecosystem's nutrient dynamics and exports. The objective is to assess whether the retention of dead wood—compared to conventional salvage harvesting practices—promotes sufficient natural forest regeneration while simultaneously providing ecological and economic services, thereby enabling the sustainable development of climate-resilient and economically viable forest stands in calamity areas.
Funding program “Sustainable Renewable Resources” (FPNR)External link of the Agency for Renewable Resources (FNR), funded by the Federal Ministry of Agriculture, Food and Regional Identity (BMLEH)External link.
Works in spring 2026 included modifications of the deadwood manipulations, soil sampling, retrieval of litterbags, and installation of sensors.
Image: Fabian Löber
The plot‑wise treatments “cleared plot” and “lying deadwood” (in the background) were created using a harvester.
Image: Klara Mrak
Landscape shaped by the disturbance events of recent years (drought and bark beetle infestation); example from Thuringia.
Image: Alexander Tischer
High stand on the “Standing Deadwood” plot.
Image: Klara Mrak
Klara Mrak and Dorothea Peter (Soil Science, FSU Jena) mapping humus forms..
Image: Sascha Spaleck
Intact spruce stand
Image: Klara Mrak
The spruce trees on the “Intact Spruce” plots form a relatively closed canopy.
Image: Klara Mrak
The plot‑wise treatment “Lying Deadwood” was created using a harvester.
Image: Klara Mrak
Litterbags will be retrieved by M.Sc. student Annika Weigel to investigate soil faunal activity and its effect on decomposition.
Image: Klara Mrak
M.Sc. students Aina Vorberger and Annika Weigel (FSU Jena) on the “Standing Deadwood” plot.
Image: Klara Mrak
M.Sc. students Johannes Baumeister and Alex Borrmann installing the soil sensor network in March 2026.
Image: Klara Mrak
Organic layer at the plot "Standing Deadwood"
Image: Klara Mrak
