Too wet for the beetle

Created: 01/25/2022, 16:21

By: Dominik Goettler

Drilled into: A piece of spruce bark that was attacked by the bark beetle.

Significantly less damaged wood was produced last year.

© Lino Mirgeler/DPA

Breather for Bavaria's forests after the dry years: the bark beetle can't cope with the damp weather.

Munich – breathe easy in the state forest.

Last year, less wood was damaged by the bark beetle than it has been in six years.

This was announced by the Bavarian State Forests at the weekend.

At around 710,000 cubic meters, the amount of beetle wood was well below the value of previous years: compared to the hot year 2019, the number even fell by more than half.

The fact that the voracious beetle was not able to spread so much in Bavaria's forests last year is mainly due to the weather, as explained by Ludwig Straßer from the forest protection department of the State Institute for Forestry and Forestry.

"In 2021 it was significantly cooler than in previous years and it rained more," he says.

And the bark beetle doesn't like that at all.

Because its larvae are dependent on heat, they develop much more slowly when it is cooler.

"In high humidity, they are also at risk of fungal diseases," says Straßer.

After several years of drought, which acts like a breeding chamber for the beetle, the heavy rainfall has also made the stressed spruces more robust again.

The bark beetle prefers to attack them.

But if the trees can form enough resin, the beetle that bore in can be flushed out.

"Or the larvae drown in the Harz Mountains," explains Straßer.

However, this natural defense mechanism only works if the beetle masses do not become too large.

However, the all-clear does not apply to all of Bavaria. The state forests identified a clear north-south gradient. While the damage in Upper Bavaria was relatively low, the Franconian Forest remains one of Bavaria's bark beetle hotspots. And not only in the state forest, but also in private forests. "Actually, we were lucky with the weather last year," says Hans Ludwig Körner, Managing Director of the Bavarian Forest Owners' Association. “But in Franconia we have members whose entire forest has been destroyed. A life’s work simply goes under.” In the long term, the only thing that will help in the long term is the conversion to stable mixed forests, which has been going on for years and is being funded with a lot of money by the state government. Because even if there was a little breather last year:"The trend towards warmer and drier weather will continue," says Ludwig Straßer.

However, the number of bark beetles that forest owners can expect this year cannot really be foreseen.

"It's looking very good at the moment, we've had good rainfall in the past few weeks," says Straßer.

But he also knows: "It can quickly tip over."

The state forests are confident: "Due to the less damage and the planned continuous processing in the Bavarian state forests, we expect significantly lower damage figures in 2022 than in recent years - provided the weather cooperates," says spokesman Jan-Paul Schmidt.

With a view to the wood market, he also makes it clear that despite the lower amounts of damage in the Bavarian state forests, there is enough coniferous wood to be able to meet the continued high demand.