Forests: Study says spruce beetle not a big factor in recent southwest Colorado wildfires


A major spruce beetle outbreak has been spreading across forests of southwest Colorado, but that hasn’t been a big factor in recent wildfires in the region, according to CU-Boulder research.

Climate, topography likely more significant, researchers say

Staff Report

Colorado researchers have added another chapter to the long-running debate over beetle-kill and wildfires, finding that spruce beetle infestations haven’t increased the severity of wildfires in southwestern Colorado.

Spruce bark beetles have affected roughly half a million acres of Engelmann spruce and subalpine fir forests across the state in recent years, with infestations documented across an additional 87,000 acres in 2014. Continue reading

Environment: More maple tree woes


What’s up with maple trees?

Study documents widespread growth slowdown

Staff Report

An extensive tree-ring study in the Northeast suggests a widespread and steady decline in the health of sugar maples, one of most economically and ecologically important trees in the eastern United States and Canada.

The decline started showing up in the 1970s a decline in the growth rate of of sugar maple trees, but the reasons are still unclear, according to the State University of New York researchers who recently published their findings in the open-access journal “Ecosphere.” Continue reading

Study says some forests may not recover from mega-disturbances in the global warming era

Colorado aspens

There have been significant die-backs in Colorado aspen forests during recent hot droughts and the stands may never regenerate in some areas because of global warming. @bberwyn photo.

Giant fires, insect outbreaks could be ‘game-changer’ for some forests

Staff Report

FRISCO —Forest Service researchers say “mega-disturbances” like giant wildfires and insect outbreaks are likely to hasten the slow demise of temperate forest ecosystems in the coming decades.

Even without those large-scale events, some forests appear to be transitioning to shrublands and steppe, and big disturbances could speed that process, according to a new study published this month in Science. Continue reading

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


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’


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


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