Study: Western pine beetle outbreak may have weakened next generation of trees by wiping out key fungi

Hawk's wing Colorado mushrooms

Important mushroom species that help trees grow were wiped out by the mountain pine beetle epidemic, potentially leaving future forests more susceptible to renewed insect attacks. @bberwyn photo.

Widespread mushroom die-off dramatically lowers seedling survival rate

Staff Report

FRISCO — The recent pine beetle outbreak in western forests may have left the next generation of trees more vulnerable to future pests, Canadian researchers concluded in a new study that examined how the wave of tree deaths affected fungi that grow together with lodgepole pines.

Many trees, including lodgepoles, are partly dependent on certain fungi that enable a nutrient exchange at the cellular level. But the pine beetle outbreak was so widespread that many of the beneficial fungi disappeared. Continue reading

New bug outbreak hitting Colorado trees

State foresters say pine needle scale infestation may be linked with heavy use of pesticides in war against pine beetles

Pine needle scale is weakening and killing conifer trees in the Colorado mountains.

Pine needle scale is weakening and killing conifer trees in the Colorado mountains, possibly as a result of the earlier heavy application of pesticides used to try and kill mountain pine beetles. @bberwyn photo.

By Bob Berwyn

FRISCO — Colorado forest experts are documenting an unprecedented outbreak of pine needle scale on conifer trees in Grand, Summit and Eagle counties that may be linked with the widespread application of pesticides used several years ago to try and kill mountain pine beetles.

The intensive use of those pesticides may have wiped out beneficial insects like predatory wasps and beetles that keep pine needle scale in check, said Granby-based Ron Cousineau, district forester for the Colorado State Forest Service.

“Most of the concentrated spray for mountain pine beetle ended about three, four or five years ago. That’s when we started seeing the buildup of pine needle scale,” Cousineau said. Continue reading

Global warming drives huge Alaska forest shift

dfg

Study tracks shift in boreal forest.

‘This is not a scenario model, or a might, or a maybe …’

Staff Report

FRISCO — There’s little doubt that global warming will drive massive shifts in plant communities around the globe, and in Alaska, researchers have already been able to document those changes at the forest scale.

White spruce tree growth in interior of the state has declined to record low levels, while the same species in Western Alaska is growing better than ever measured before.

“For the first time across a major forest region, we have real data showing that biome shift has started,” said University of Alaska Fairbanks School of Natural Resources and Extension researcher Glenn Juday.

“This is not a scenario model, or a might, or a maybe. The boreal forest in Interior Alaska is very near dying from unsuitably warm temperatures. The area in Western Alaska where the forest transitions to tundra is now the productive heart of the boreal forest,” Juday said. Continue reading

Warming temps not the only factor in beetle outbreaks

Study shows regional variations in forest health equation

Annual aerial survey enable resource managers to map the spread of tree-killing bugs.

Annual aerial survey enable resource managers to map the spread of tree-killing bugs.

Staff Report

FRISCO — Warming winters across the western U.S. have had a nuanced effect on the severity of mountain pine beetle outbreaks, researchers said last week.

The absence of lengthy bug-killing cold snaps in some areas has helped fuel the growth of insect populations,, but milder winters can’t be blamed for the full extent of recent outbreaks in the region, according to a study by Dartmouth College and U.S. Forest Service. Continue reading

One more time: Beetle-killed forests are NOT more likely to burn, according to new CU-Boulder study

asdf

Beetle-killed lodgepole pines in Colorado. bberwyn photo.

New CU-Boulder study has implications for forest managers and Red Zone communities

Staff Report

*More Summit Voice stories on beetle-kill and forests here.

FRISCO — Communities and resource managers looking to address the threat of wildfires should focus less on tree-killing beetles and more on the underlying forces driving the trend toward larger fires.

Warmer temperatures and increased drought are the key factors, said Colorado-based researchers who took a close look at patterns of beetle-kill and wildfires in recent years.

Their study found that western forests killed by mountain pine beetles are no more at risk to burn than healthy forests. Those findings  fly in the face of both public perception and policy, the scientists acknowledged.

“What we are seeing in this study is that at broad scales, fire does not necessarily follow mountain pine beetles,” said CU-Boulder Research Scientist Tania Schoennagel, of the Institute of Arctic and Alpine Research. “It’s well known, however, that fire does follow drought.” Continue reading

Aerial survey shows pine beetles waning, but spruce beetles continue to spread across Colorado forests

Aerial surveys help track forest changes over time

sdfg

Nearly every mature spruce has been killed by spruce beetle in this drainage on the Rio Grande National Forest.Photo: Brian Howell.

Spruce beetles are spreading quickly in southwestern Colorado.

Spruce beetles are spreading quickly in southwestern Colorado. Graph courtesy USFS.

By Bob Berwyn

FRISCO — There’s good news and bad news from Colorado’s forests. Mountain pine beetle activity has faded to the lowest level since 1996, but spruce beetles continue to spread in the San Juans and in northwestern Colorado.

The spruce beetle outbreak was detected on 485,000 acres in 2014, compared to 398,000 acres across the state in 2013, according to the U.S. Forest Service and the Colorado State Forest Service. The annual aerial survey by the two agencies shows that the spruce beetle outbreak expanded to 253,000 new acres. Continue reading

Study: Small trees key to long-term forest survival

sdfg

Forest treatments that focus on removing smaller trees may not be the best tool for western dry forests, according to new research by University of Wyoming scientists.

Study shows many treatments in western dry forests are misguided

By Bob Berwyn

FRISCO — Mid-elevation forests in the western U.S. have survived centuries of drought, wildfires and insect onslaughts by hedging their bets with a diversity of tree sizes, Wyoming researchers said after studying forest plots from the Pacific Northwest down to Arizona and New Mexico.

The research showed that the biggest threat to those forests is from insects and not wildfires. Historically abundant small trees enable those forests to rebound after tree-killing bugs move through. Continue reading

Follow

Get every new post delivered to your Inbox.

Join 8,770 other followers