Swiss forests need intervention to survive future climate

A key impact of climate change on forests will be the shifting of vegetation zones to higher altitudes. Keystone

Forests in Switzerland can adapt to a certain extent to climate change but will need forward-thinking management to remain productive and provide ecological services, say experts.

The Swiss environment ministry and the Swiss Federal Institute for Forest, Snow and Landscape Research  (WSL) have presented key recommendations based on a seven-year research programme dedicated to understanding how best to help Swiss forests weather climate change.

At a press conference in Birmensdorf, Zurich on Monday, the study leaders said that the results provide a first comprehensive view for central Europe of the impacts of climate change on forest species, and the multiple services that forests provide.

They said that climate change will have a profound impact on Swiss forests, resulting notably in the shifting of vegetation zones some 500-700 metres (1,640-2,297 feet) higher in altitude, as well as more frequent periods of drought, forest fires and pest infestations.

Trees that germinate and begin growing in Switzerland today will already experience a marked change in climate during their lifetime, the researchers said. They emphasised that adapting our forest management practices will be essential to helping Swiss forests survive climate change, and continue to provide the key services humans rely on, such as wood production and shelter from natural hazards.

A warmer Switzerland

The average temperature in Switzerland has already increased about 1.9 degrees Celsius since the beginning of  industrialisation. If, as the COP21 Paris AgreementExternal link stipulates, world warming is limited to 1.5 or 2 degrees Celsius by the end of the century, we should still expect an additional rise of 1-2 degrees Celsius.

Warmer temperatures mean that broad-leaved trees will replace the conifers (cone-bearing trees like spruces or pines) that we commonly see in low-altitude mountain forests today. In addition, the temperature increase and greater frequency and intensity of drought during plant growing seasons will create stress for trees, exacerbating the risk of forest fires and pest infestations.

No choice but to adapt

Foresters and forest owners should take this information into account now and adapt their management practices accordingly, the researchers said.

A key outcome of their research was a series high-resolution maps, which show fine variations in growth conditions including soil depth, water supply and slope exposure, to aid in forest planning.

The researchers are also currently working on specific tree species recommendations in a series of tests carried out in collaboration with cantonal forestry offices and associations of forest owners, wood industry representatives and environmental protection advocates.

Launched in 2009, the research programme included 42 projects by a number of Swiss research institutions, notably the University of Basel and the Swiss Federal Institute of Technology ETH Zurich.

The full 500-page version of the researchers’ report, “Forests and Climate Change”, will be made available by the WSL at an official presentation at their “Knowledge Forum” conference on November 29.