Beetles Turn Germany’s Climate-Stressed Forests Into Ecological Graveyard

WELZOW: Germany’s forests have long been treasured by its people, so the country has reacted with alarm and dismay as a beetle infestation has turned climate-stressed woodlands into brown ecological graveyards.
After two unusually hot summers in a row, vast patches of the forests mythologised by medieval fairytales, Goethe’s writings and Romantic painters have turned into tinder-dry dead zones.

Given the scale of the threat to the one third of German territory covered by trees, Chancellor Angela Merkel’s government convened a “national forest summit” on Wednesday.

There Agriculture Minister Julia Kloeckner pledged 800 million euros (about $880 million) in federal and state funds over four years to restore the 180,000 hectares of forest destroyed by drought and pests as well as storms and fires — the equivalent of 250,000 football pitches.

The chief culprit has been the tiny bark beetle, which has gone on a rampage as trees in water-starved habitats have lost their natural defences.

In vast parts of Germany, like Welzow forest 100 kilometres (60 miles) south of Berlin, once healthy trees have become defoliated skeletons, their trunks marked by tell-tale networks of tiny tunnels.

“The insect eats the bark and lays eggs inside,” said forest ranger Arne Barkhausen. “The larvae then start to eat the trunk and block the nutrient pathways of the tree, which dies in about four weeks.”

Source: Beetles Turn Germany’s Climate-Stressed Forests Into Ecological Graveyard – NDTV,2019-09-27

Variable tree growth after fire protects forests from future bark beetle outbreaks

Do severe wildfires make forests in the western United States more susceptible to future bark beetle outbreaks?

The answer, in a study published Monday (Nov. 7, 2016) in the Proceedings of the National Academy of Sciences, is no. By leading to variability in the density and size of trees that grow during recovery, large fires reduce the future vulnerability of forests to bark beetle attacks and broad-scale outbreaks.
“Fire creates a very heterogeneous landscape,” says study co-author Kenneth Raffa, professor of entomology at the University of Wisconsin-Madison. “Beetles can only reproduce in an individual tree once, so they take advantage of this patch of trees and that patch of trees as they become available, but when the number and size of trees vary a lot, it’s hard for a large outbreak to develop.”

Read more at: http://phys.org/news/2016-11-variable-tree-growth-forests-future.html#jCp

Source: Variable tree growth after fire protects forests from future bark beetle outbreaks

How bark beetles use mob mentality to kill millions of California trees

There are killing machines on the loose in California and the entire Western region.

They’re found in packs and look for the weak but they’re not the scary predator you’d imagine. In fact, they’re about the size of a rice grain.

They’re called bark beetles.

A June 2016 Cal Fire report stated the ongoing drought in combination with the tiny insects are responsible for killing about 66 million trees in California since 2010. That’s up from 29 million trees in 2015 and 3.3 million in 2014, according to the report.

Source: How bark beetles use mob mentality to kill millions of California trees | ABC10.com

Dead trees are fueling California wildfires, but what’s killing the trees?

California has suffered more than 5,000 wildfires this year, and we’ve only reached the beginning of the season. Just last week, more than 10,000 firefighters were battling blazes throughout the state – fires largely fueled by already-dead, dry trees.

But many of those trees aren’t dying of old age. They were killed by one tiny culprit: the bark beetle.

Source: Dead trees are fueling California wildfires, but what’s killing the trees? | KALW