How bark beetles are destroying German forests more and more

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Dhe looks like a battlefield. Between sawn off branches, broken wood and bark, only tree stumps protrude from the earth. The ground under your feet crunches, with every step you can hear the cracking of dead branches. Until two months ago there was still thick spruce forest here, says Ralf Bördner, head of the Wiesbaden-Chausseehaus forestry office. “I don’t think the spruces will be standing next to it at the end of the year either,” he says, pointing to the trees on the edge of the bare surface.

If you look at the network of fine lines on the inside of the bark, it quickly becomes clear who is responsible for it: the ravenous bark beetle. In normal years, the spruce defends itself against the pest, which is only a few millimeters in size, by forming resin. If the tree suffers from a lack of water, this natural defense mechanism is disturbed. As in the past two years, it is too dry in large parts of Germany this summer. Although it rains more often in many regions, it is also not quite as hot in many places. But the amounts of rain are not enough to penetrate deeper layers of the soil. The floor is dusty, the undergrowth is parched. Pests are easy.

“The bark beetle dynamics are amazing,” explains Förster Bördner. “Since the end of 2018 we have basically been doing nothing more than chasing the beetles.” In order to limit the spread, the infected trees have to be quickly removed from the forest, because after six weeks new beetles hatch and pounce on the surrounding ones Trees. However, this is often easier said than done, in many cases there is a lack of machinery and labor to cut down the trees. And even if the wood can be removed quickly, it is not said that there is also a customer for it.

Supersaturated wood market

Currently, it usually takes several months for the wood to be transported from the forest to the sawmill, explains Bördner. “Many customers are over-saturated.” Due to the storms and pest infestation, the amount of wood removed from German forests rose by around a fifth in 2018 and 2019 compared to the long-term average. The proportion of damaged wood even climbed to more than 50 percent.

Destroyed forest: Because bark beetles infest the trees, the Wiesbaden foresters have to cut down areas again and again.

Due to the wood spoilage, the prices are now on the floor: If up to 95 euros per solid meter were called for the standard quality of spruce in early 2019, today it is not even 30 euros. At the same time, forest owners incur additional costs if they have to store the wood infested by beetles in the forest for a longer period of time. In order to prevent the bark beetle from multiplying under the bark, the stacked wood must either be sprayed with pesticides or – the Wiesbaden Forestry Office also relies on this – the bark must be removed with modern harvesting machines. In addition to the harvest costs of around 20 euros per cubic meter, 3 to 6 euros are added depending on the procedure.

Forester Ralf Bördner heads the Wiesbaden-Chausseehaus forestry office

Often there is no profit left – if the wood can be deposited at all, says Bördner and points to the numerous piles of tree trunks, so-called polters, that line the forest path. So it was understandable that forest owners were increasingly considering whether they should still harvest the wood and incur costs just so that it would lie on the edge of the forest.

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