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Forests: Spruce beetles spreading fast in southern Rockies

State report details status of insect activities

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Spruce beetles are widely active across the mountains of southern Colorado.

Staff Report

FRISCO — Windstorms, mild winters and drought are the key factors in the continued spread of spruce beetles, which have become the dominant change agent in Colorado forests the past few years.

According to the latest annual forest health report compiled by state forest experts, spruce beetles were active across 398,000 acres in 2013, affected more than triple the amount of acreage than mountain pine beetles. Continue reading

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Good news, bad news for Colorado forests

Pine beetle infestation slows, but spruce beetles continue to spread

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Healthy spruce-fir forest at Vail Pass. bberwyn photo.

By Summit Voice

FRISCO — There’s good news and bad news for Colorado forests, according to state and federal officials, who said last week that the mountain pine beetle epidemic slowed dramatically in 2013, while spruce beetles continued to spread.

Statewide, mountain pine beetles were active on 97,000 acres in 2013, the lowest acreage of active infestation in 15 years. Since 1996, mountain pine beetles have killed trees across 3.4 million acres.

Spruce beetle were active on 398,000 acres, expanding by 216,000 new acres in 2013, compared to 183,000 new acres in 2012. The total area affected by this beetle since 1996 has reached more than 1.1 million acres. Continue reading

Study: Drought the prime driver of spruce beetle outbreak

Long-term climate shifts linked with historic spruce beetle episodes in Colorado

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A Colorado spruce forest near Shrine Pass, Colorado.

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Spruce beetles are spreading rapidly and killing trees in the southern Rockies.

By Summit Voice

FRISCO — The current spruce beetle outbreak in Colorado’s high country has the potential to grow larger in scope than the recent mountain pine beetle epidemic that killed mature lodgepole pines across millions of acres.

And the trigger of for the spruce beetles is drought that’s linked with long-term changes in sea-surface temperatures in the Northern Atlantic Ocean, a trend that is expected to continue for decades, according to a new study by scientists with the University of Colorado, Boulder.

The new study is important because it shows that drought is a better predictor of spruce beetle outbreaks in northern Colorado than temperature alone, said Sarah Hart, a CU-Boulder doctoral student in geography. Continue reading

Environment: Are Colorado’s majestic high country spruce forests next on the bark beetle hit list?

Global warming is likely to increase insect populations and make trees more susceptible to attacks

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So far, high-elevation spruce-fir forests in Summit County have been relatively free of spruce beetles, with the exception of a hotspot in the Baylor Park area, near Ski Sunlight. Spruce beetle activity south of Breckenridge has slowed down. Bob Berwyn photo.

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Spruce beetles are spreading quickly in the San Juans.

By Bob Berwyn

SUMMIT COUNTY — The mountain pine beetle epidemic has run its course in the Colorado high country, but there’s a new bug on the rise.

Spruce beetles have killed huge swaths of mature spruce beetles in southwestern Colorado, especially on the Rio Grande National Forest — and they appear to be moving north.

Researchers and resource managers are trying to get ahead of the curve to anticipate how far the outbreak will spread in Colorado’s 4.7 million acres of spruce-fir forest, and how the bugs  may affect wildfire behavior and ecosystem services in a zone where large fires are rare. Continue reading

Colorado: Pine beetle epidemic wanes

Spruce beetle infestation grows in southwestern mountains

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Aerial surveys show that spruce beetles are spreading in SW Colorado, while pine beetles slow their attack in the northern and central part of the state.

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The spread of mountain pine beetles slowed to levels last seen in 2003.

By Summit Voice

SUMMIT COUNTY — Mountain pine beetle activity in Colorado dropped dramatically in 2012, to the lowest level in 10 years, according to state and federal officials who this week released the the results of their latest aerial surveys.

Mountain pine beetles are still spreading across parts of the mountains between Estes Park and Leadville, but new activity was reported on just 31,000 acres, down from 141,000 acres in 2011. Since the outbreak started in 1996, beetles killed trees across more than 3.4 million acres, but it’s important to remember that not every single tree died.

In the aftermath of the infestation, foresters are finding that pockets of younger trees survived the wave of beetles, even in the hardest-hit areas. Continue reading

Forest mortality declines across the U.S.

Pine beetles running out of food, spruce beetle infestation growing

Mountain pine beetle mortality is on the decline across the western U.S.

Spruce and fir mortality is on the increase in Colorado.

By Bob Berwyn

SUMMIT COUNTY — Tree mortality from insects and diseases has dropped dramatically in the past few years, mainly because mountain pine beetles are running out of food, according to a new report from the U.S. Forest Service.

But the next significant cycle of insect infestation has already reached epidemic proportions in the south-central Rockies, where spruce beetles are devastating stands of mature spruce trees. The spruce beetle outbreak has been especially intense in the San Juans, where the bugs have killed almost every single mature tree from the creek bottoms all the way up to high-elevation krummholz.

It will be interesting to see if the numbers go back up after this summer’s drought weakened trees across the region.

Continue reading

Climate: Bark beetles on the rise in Europe

Norway Spruce.

Attacks increase when temperatures climb and precipitation dwindles

By Summit Voice

SUMMIT COUNTY — Forests in the American West aren’t the only ones facing an increasing threat from tree-killing beetles. A European researcher recently studied the pattern and impact of outbreaks by the bark beetle in the southern Alps, measuring  the size and distribution of the infested areas occurring along steep temperature gradients  between 1994 and 2009 and matched the observations with climatic changes.

The results, published online in Springer’s Climatic Change, shows that there were more attacks by the spruce bark beetle on European Alpine spruce forests over a 16 year period, as temperatures rose and rainfall dropped, according to Lorenzo Marini, of the University of Padova in Italy. Continue reading

Tree-killing bugs to spread faster in a warming world

New Forest Service research supports foregone conclusion about bark beetles

Pine beetle mortality is evident nearly everywhere in Summit County from this vantage point on Swan Mountain. A Forest Service study says outbreaks could become more frequent as temperatures get warmer.

By Summit Voice

SUMMIT COUNTY — Forest Service and university researchers are starting to put together some empirical evidence showing what we’ve known intuitively for a long time — global warming will increase the potential for tree-killing insect outbreaks dramatically during the coming decades.

Specifically, the researchers said spruce beetles are likely to start reproducing annually, instead of every two years.  Annual reproduction of the beetle can contribute significantly to population growth and the occurrence of outbreaks.

“Native bark beetles are responsible for the death of billions of coniferous trees across millions of acres of forests ranging from Mexico to Alaska,” said Barbara Bentz, research entomologist with the Forest Service’s Rocky Mountain Research Station and lead author of the study. “Our study begins to explain how their populations respond to the climatic changes being projected by the Intergovernmental Panel on Climate Change.” Here’s a link to an abstract of the report. Continue reading

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