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Forest under pressure: Diseases, pests and disturbances

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Forests are exposed to a wide range of disturbances, including damage caused by insects, pathogenic agents and storms. Non-native organisms also alter various ecosystems. We investigate how illnesses affect trees and forests, how they can withstand such disturbances and how well they recover afterwards.


Fungi and – in rarer cases – bacteria, nematodes, phytoplasms or viruses along with a huge variety of insects infest and cause harm to trees. Disease can cause symptoms in all parts of the tree, such as the roots (e.g. phytophthora), the bark (as is the case for bark beetles) or in the crown (ash dieback).

Trees weakened as a result of dryness, frost, poor light or nutrients are more susceptible to pests and diseases. Climate change is expected to increase infestation by harmful organisms. A warmer climate will also favour the survival of non-native pests, which trees are less well-equipped to combat than native pests.


Monitoring forest health

In the group forest entomology we are also investigating the impact of climate change on bark beetle infestation. The bark beetle is a native pest, but has the potential to cause major damage.

We manage the 'Swiss Forest Protection' centre, which monitors pest and disease infestation in the forest as well as other damage such as browsing by game or environmental influences. We diagnose forest pests, advise forestry practitioners and authorities, survey forestry commission offices about forest damage, and hold training courses.

The group phytopathology conducts research into plant diseases. We use genetic and epidemiological methods to determine the causative organisms and investigate how they spread and infest their hosts. We also look for potential organic strategies to combat these organisms. Our research helps with risk analysis, diagnostics and controlling pathogenic agents

Our research focuses primarily on quarantine organisms, i.e., particularly dangerous organisms whose proliferation in Switzerland must be prevented at all costs. We are able to examine their behaviour and disease patterns under highly secure conditions in our plant protection laboratory. We also support the Swiss Federal Plant Protection Service.


Storms, forest fire, avalanches

Extreme events such as storms, forest fires, droughts or avalanches can cause damage to larger forest areas. We investigate the significance of these events on forest development. We perform a range of experiments, e.g. to test how resistant certain types of trees are to arid conditions and how long repopulation takes after a forest fire. More extreme events of this kind are expected as climate change continues its rapid advance. In the light of rising demand for wood, the significance of such disturbances will increase.



Swiss forest protection

We diagnose forest diseases and inform the authorities, pracitioners and the public about forest protection.

Forest diseases

Various agents trigger diseases in forest trees. We diagnose and monitor these agents in order to find methods of controlling them.

Forest pests

All kinds of animals attack forest trees. In protection and commercial forests, this natural process is usually undesirable and measures are taken to...


We study natural enemies of forest pests in order to identify ecologically safe control measures.

Storms and windfall

Storms Vivian (1990) and Lothar (1999) affected large forest areas in Switzerland. We studied their consequences over a long period of time.

The consequences of forest fires

Forest fires destroy habitats and compromise the protective function of the forest, but species diversity is astonishingly high after a forest fire. ...


Further information