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

Wildfire season starts slow for 2d year in a row

Continued Western drought, warmth set stage for significant wildfires later this summer

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After a dry and warm winter, southern Alaska will have a better than average chance of signficant wildfire activity this spring. Map via NIFC.

By Bob Berwyn

Western wildfires have always been shape-shifting beasts, roaring to life wherever there is hot and dry weather, wind and fuel. But last year’s relatively cool and wet summer brought relief to parts of the region — including Colorado — that had been especially hard the previous few years.

The 2015 wildfire season is starting similarly slow to last year, according to statistics from the National Interagency Fire Center showing that, since January 1, there have been about 6,200 fires that burned across a 100,000 acre footprint, just 30 percent of the average from the past 10 years. Continue reading

Genetic research helps forest scientists determine which trees can survive global warming

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Can forests evolve to survive global warming?

Research will inform forest planning efforts

Staff Report

FRISCO — Spanish scientists say they can use genetic data to help determine which pine trees are most vulnerable to climate change, and which trees might be able to thrive in a warmer world. Their findings, published in GENETICS, could help forestry managers decide where to focus reforestation efforts and guide the choice of tree stocks.

The study focused on maritime pines, which grows widely in southwestern Europe and parts of northern Africa. But the tree’s important economic value and ecological roles in the region may be at risk as the changing climate threatens the more vulnerable forests and the productivity of commercial plantations. Continue reading

Global warming: California’s majestic redwoods at risk

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Redwoods at risk. bberwyn photo.

New study pinpoints climate-change threats to Pacific Northwest rainforests

Staff Report

FRISCO — Huge reservoirs of biodiversity in the rainforests of the Pacific Northwest are at risk as global warming reshapes climate conditions in the region.

Suitable habitat for majestic coastal redwoods could shrink by 23 percent, and other species like Alaska’s yellow cedars are already dying back as temperatures warm.

“In the Pacific Northwest, the glass is half empty as the climate may no longer support rainforest communities like coast redwood,” said Dr. Dominick A. DellaSala, Chief Scientist of Geos Institute, announcing the results of a recent study that focused on the future distribution of eight rainforest conifers across a 2,200-mile stretch of coastal rainforests in the Pacific Northwest, British Columbia, and Alaska. 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

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