Heat saps Swiss forests

Switzerland's forests have wilted in the heat. WSL

The hot, dry summer has taken its toll on Switzerland’s forests.

The leaves on thousands of trees are already changing colour and dying, something which should not happen for another two months.

Forestry workers say the early autumn is the trees’ way of coping with lack of water, and might help them survive the unusual heat.

But the trees are left in a weakened condition, and more easily fall victim to parasites such as the bark beetle.

In the last comparably hot summer, in 1947, over 100,000 cubic metres of forest died because of the dryness and intense heat.

The Swiss Federal Institute for Forest, Snow and Landscape Research warns that while the trees will not die immediately, in the long term many thousands will not survive the damage they are suffering now.

Spruce and beech trees in particular are expected to be seriously depleted over the next two to three years, unless heavy rain falls in the next few weeks.

The worst affected regions of Switzerland are the Alps and pre-Alps, in particular the western part of the Bernese Oberland.

Root and branch

Forestry workers have noted greatly increased activity of bark beetles on the trees.

The parasites have taken advantage of the hot dry weather to breed in increased numbers. And forestry workers say types of bark beetle normally thought of as rare are being seen much more often.

Infestations of bark beetles usually cause such damage that the affected trees have to be cut down.

And while the bark beetle and the heat are affecting the trees’ leaves, diseases such as fungal infections, many of them untreatable, are threatening their roots.

The forestry office believes the weakened condition of the trees means there is a greatly increased risk of widespread disease.

Switzerland’s forests are still recovering from the catastrophic damage caused by Hurricane Lothar at the end of 1999.

swissinfo with agencies

In brief

Switzerland’s trees are dying and changing colour; the early autumn is a reaction to the intense heat.

The hot dry summer leaves the trees vulnerable to parasites such as the bark beetle, and to fungal infections.

Following the last comparably hot summer in 1947, over 100,000 cubic metres of trees died.

The full extent of the damage will not be seen for another two or three years.

Last week more than 400 firefighters and soldiers tackled the biggest forest fire in Switzerland for 30 years.

Hundreds of people were temporarily evacuated from their homes near the spa town of Leukerbad in canton Valais.