In mid-April, heavy and unexpected snow fell on valais. Under its weight, tens of thousands of trees collapsed.Today, the forests remain congested with trunks that the loggers try to evacuate as quickly as possible. Beyond visual damage, the challenges are environmental and health.

“This one is infested. There, we have a larva. If we do nothing, it will really give substrate to the pests who will be able to develop without any obstacle, and it is indeed not onyl going to touch the wood which was put on the ground by heavy snow, but also the woods which are healthy all around,” explains Friday in the 7:30 pm Michaël Roux, engineer in the Nature Landscape.

“We really want to prevent it from spreading and that it brings even more prejudice to the protection function on the forests,” he continues.

Risky Torrents and Major Work

The situation is not limited to lying trees. In Pratlong, for example, the fallen trunks clutter the torrent bed. A threat to infrastructure in the event of bad weather.

“In the event of large thunderstorms with surveyed water climbs or even torrential lavas, there is a risk of plugs with bridges, works, pipes, deterioration of banks and also a risk of overflow,” explains Olivier Bourdin, gardas and director of forestry sorting of Thyon.

The challenge is size: a hundred torrents must be uncluttered just in the town of heremence. Slow and challenging work. “It’s a hundred meters a day. After two and a half months,we have almost 60% of the work to be carried out. It is considerable,” admits Olivier Bourdin.

To optimize the intervention, a laser detection technology made it possible to establish a precise mapping of the damage in the Val d’Hérens. This overview facilitates work planning, which should still last several months in the most affected sectors.

Claudine Gaillard Torrent/ther