People in many places are struggling under the summer heat. Trees are suffering too, especially when rainfall is also absent. Once again, the weather is becoming a defining factor for forest health in Austria. High temperatures and solar radiation are intensifying the water shortage, as evaporation increases.

The first half of this year was once again very warm and very dry in Austria. Across the national area average, temperatures were +1.8 °C above the 1981–2010 mean. Nationwide, rainfall was 30% below the long-term average. In some regions, such as around Vienna, in the Bregenzerwald, or in the Innviertel, precipitation deficits were as high as 50–70%, as ZAMG reports. The drought in July is particularly dramatic. Affected areas include the north-east, east and south of Austria, western Upper Austria, the Salzburger Flachgau, and Vorarlberg. Rainfall for Bregenz, for example, amounted to just 90 mm.

"This weather situation is not without consequences for tree vegetation. Leaves are already changing colour earlier. In maples and linden trees, for instance, you can see typical brown necrosis on the leaf margins, and in linden trees there are also some yellow leaves," says Gernot Hoch, forest protection expert at the Federal Research Centre for Forests (BFW). Also noticeable since the end of July are the beech trees, whose brown-coloured crowns are already visible from a distance even in forested areas.

How does drought affect trees?

Read the full article at bfw.gv.at