Storm of the century Storm "Lothar" has changed forest management

SDA

26.12.2024 - 05:31

Storm "Lothar" caused huge damage 25 years ago. (archive picture)
Storm "Lothar" caused huge damage 25 years ago. (archive picture)
Keystone

25 years after the storm "Lothar", the Swiss forest is better prepared for such a once-in-a-century event. According to the Swiss Federal Institute for Forest, Snow and Landscape Research, important lessons have been learned from the disaster.

Keystone-SDA

Hurricane "Lothar" swept across Switzerland on the morning of December 26, 199. 14 people died. The storm also threw 14 million cubic meters of wood to the ground. According to the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), "Lothar" was by far the most severe winter storm in Europe and Switzerland.

"Lothar showed us the damage that extreme events can cause," said Thomas Wohlgemuth from the WSL. On the Central Plateau, the extent was unprecedented, one would say "unbelievable today". According to the research institute, a further 17 forest owners lost their lives during the clean-up operation, as well as two people in public forestry operations.

Timber prices rose

In the years that followed, the Federal Office for the Environment (FOEN) put the total damage at CHF 1.35 billion, CHF 600 million for buildings and CHF 750 million for the forest. In total, two percent of the trees in Switzerland were knocked over or snapped.

The cantons of Bern, Fribourg, Lucerne and Nidwalden were the hardest hit by the hurricane, which moved from northern France across southern Germany and Switzerland to Austria with peak winds of up to 272 kilometers per hour (km/h).

The forestry and timber industry was hit hard as a result. Prices for round timber fell by around a third due to the oversupply in spring 2000.

The bark beetles followed

After the storm, and then especially after the hot year of 2003, mass propagations of bark beetles added almost two thirds as much damaged wood as the storm itself. When powerful storms overturn forests over large areas, a strong increase in bark beetles almost always follows in spruce-rich stands for several years, as the WSL explained.

This first affects the edge of the storm areas, and then also the adjacent, weakened stand. Particularly in low-lying areas, it is therefore important to clear damaged spruce trees, i.e. those trees that are preferred by bark beetles, as quickly as possible.

Spruce is not actually native to the Central Plateau. However, the forestry industry has planted large areas of spruce because it is well suited to timber production.

More robust forests

According to the WSL, spruce trees are now much rarer on the Central Plateau. This means that the forest is better prepared for a storm event of the century than it was in 1999.

According to the WSL, 10 to 20-metre-high trees are now standing again where the forest was on the ground 25 years ago. Many deciduous tree species that are considered climate-resistant, such as oak, cherry, sycamore and Norway maple, grew back on the storm areas.

As studies by the research institute show, many forests became more structurally diverse after the storm, creating new habitats for many animal and plant species. According to the WSL, insect diversity has virtually exploded as a result. A study by the Swiss Ornithological Institute also showed that woodpeckers were able to benefit from Lothar, as they feed on insects under the bark of trees or in rotten wood.

However, it can be assumed that sooner or later there will be major storms again, according to the research institute. Stronger storms than Lothar are difficult to imagine in Europe, but cannot be ruled out with climate change.

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