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

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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

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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

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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

What drives extreme fires? It’s mostly the weather

Forest Service scientists study aftermath of Rim Fire to assess effectiveness of forest health treatments

A NASA Earth Observatory image shows smoke plumes from the Rim Fire in August, 2013. NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response.

A NASA Earth Observatory image shows smoke plumes from the Rim Fire in August, 2013. NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response.

Staff Report

FRISCO — A detailed new study of fire behavior of the 2013 Rim Fire in Yosemite provides a nuanced view of the effectiveness of forest health treatments.

The Rim Fire was the largest recorded fire in the Sierra Nevada region, and U.S. Forest Service researchers said in their study that the fire burned with moderate to high intensity on days the Rim Fire was dominated by a large pyro-convective plume, a powerful column of smoke, gases, ash, and other debris — regardless of the number of prior fires, topography, or forest conditions. Continue reading

Humble fungi may aid whitebark pine recovery

PHOTO COURTESY USFS/RICHARD SNIEZKO

Can mushrooms help save whitebark pines? Photo courtesy U.S. Forest Service.

Scientists report success in treating seedlings with mushroom spores

Staff Report

FRISCO — High-elevation whitebark pines are under the gun in the northern Rockies. White pine blister rust, an invasive fungus, and pine beetles have combined to drive the species toward extinction.

But scientists trying to recover the species say that a humble mushroom could help their efforts. A three-year experiment shows a 10 to 15 percent increase in the survival rate of whitebark pine seedlings when Siberian slippery jack spores are injected into the soil around them. The injection takes place in nurseries before the seedlings are transplanted in the mountains. Continue reading

Climate: Logging leads to long-term release of carbon from soils in Northeastern hardwood forests

Findings challenge carbon-balance assumptions of woody biomass energy boosters

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A forest health logging site on Swan Mountain near Dillon, Colorado. bberwyn photo.

Staff Report

FRISCO — Logging forests may have a more significant impact on carbon storage in soils than previously believed, Dartmouth College researchers found after taking a close look at at how timber harvesting affects mineral soil carbon over 100 years.

The study found that, while logging  doesn’t immediately release carbon stored in a forest’s mineral soils into the atmosphere, it triggers a gradual release that may contribute to climate change over decades. Continue reading

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