Climate: Scientists warn of boreal forest ‘tipping point’

Climate zones in boreal forests are shifting northward ten times faster than the trees’ ability to migrate

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More monitoring, adaptive management needed in crucial forest zones.

Staff Report

FRISCO — The world’s vast boreal forests, stretching around the globe at high latitudes, could reach a climate tipping during this century, according to a team of international researchers who said there needs to be more attention on climate mitigation and adaptation with respect to these forests.

Boreal forests make up about 30 percent of the planet’s total forest area and play a vital role in in the global climate system by capturing huge amounts of atmospheric carbon dioxide. Continue reading

New study details global warming impact to forests

‘We expect to see widespread declines in forest productivity’

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Red beetle-killed lodgepole pines in the White River National Forest near Frisco, Colorado. @bberwyn photo.

Staff Report

FRISCO — The vulnerability of the world’s forests to global warming has been widely underestimated, a group of scientists concluded after taking a hard look at all the scientific data on forest mortality.

“We expect to see widespread declines in forest productivity, changes in the species composition and dominance patterns of forest trees, a shift to smaller-sized trees, and reductions in forest extent in some regions,” said U.S. Geological Survey researcher Craig Allen, adding that, even forests in wetter parts of the world are going to be affected by rapidly warming global temperatures. Continue reading

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

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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

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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

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