Heatwave leaves Swiss trees and wildlife struggling with drought
Sunday 4th October 2026 on 19:01 in
Switzerland
Measurements show that forests across Switzerland remain short of water after the hot summer, with trees and wildlife affected by the drought, SRF reports. The Swiss Federal Institute for Forest, Snow and Landscape Research, together with other organisations, monitors 700 trees. Its measuring stations recorded a water deficit everywhere except Stillberg near Davos.
Even in Birmenstorf, where the forest still looks green, trees are too dry, says forest ecologist Frank Krumm. Repeated thunderstorms limited damage compared with other forests, but tree growth was half what it had been in previous years.
In a forest near Bremgarten, signs of the heat are visible in fallen leaves and damaged trees. A silver fir has nearly died, while a birch has few leaves left and those remaining are brown and wilted. Experts estimate that one in two trees along the southern foothills of the Jura has been damaged.
Species expected to withstand summer heat, including conifers and birches, have also suffered. The leaves of the Norway maple, considered a promising broadleaf species, show heat damage, Krumm says.
In a forest near Aarau, Aargau cantonal hunting official Erwin Osterwalder found the soil very dry. Earthworms have retreated deeper underground, leaving birds unable to reach them for food. Roe deer fawns are smaller and lighter than usual, and wildlife is moving to places with more water. Wild boars, for example, are being seen more often near larger rivers.
Osterwalder said there was no sign that more animals than usual had died in Aargau, though drought could pose an existential problem for individual animals.
The experts said they could not yet assess the long-term effects of drought and higher temperatures on plants and wildlife. The research institute is studying which tree species can cope with water shortages and warming. Krumm said the work may point to a need for different species, such as black locust, an invasive tree originally from North America that appears to tolerate dry conditions better than native trees.