Aerial forest surveys track continued spread of spruce beetles across Colorado forests

State, federal scientists track forest health

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Aerial survey results show how spruce beetles are taking a toll across Colorado’s forests, with new areas of infestation in the Sange de Cristo, the West Elks and even the northern mountains.

Spruce beetle populations are surging in the southern Rocky Mountains. bberwyn photo.

Spruce beetles are still spreading in the southern Rocky Mountains. @bberwyn photo.

By Bob Berwyn

The latest results from aerial surveys of Colorado forests shows that spruce beetles are doing the most damage, with infestations detected on 409,000 acres across the state, expanding onto 182,000 acres of previously unaffected forests. Since 1996, spruce beetle outbreaks have caused varying degrees of tree mortality on more than 1.5 million acres in Colorado.

The mapping shows spruce beetles spreading outward from the San Juans to the West Elk Mountains, the Sangre de Cristo Mountains and into the northern part of the state around Rocky Mountain National Park. See the full report here: http://www.fs.usda.gov/goto/USFSR2ForestHealth.

State forest experts said it was the fourth year in a row that spruce beetle outbreaks caused widespread tree mortality. As populations of spruce beetles expand, they are starting to affect higher-elevation stands of Engelmann spruce. The report says blowdown events, combined with long-term drought stress, warmer temperatures and extensive amounts of older, dense spruce, have all contributed to the ongoing spruce beetle outbreak. Continue reading

California drought has damaged millions of trees

Mighty redwoods.

Redwood trees in California. @bberwyn photo.

Large swaths of forest now seen as more vulnerable to future droughts

Staff Report

California’s extended drought may take a long-term toll on the state’s forests, scientists reported last month after studying severe water loss from tree canopies since 2011.

The study, published in the Proceedings of the National Academy of Sciences, says that up to 58 million large trees in California showed signs of being drought stressed, with persistently low rainfall, high temperatures and outbreaks of the destructive bark beetle combining to increase forest mortality risk. Continue reading

Environment: More maple tree woes

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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

Can California’s redwood trees survive global warming?

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Some research suggests redwood trees may start to thrive in Oregon as the climate warms along the West Coast. @bberwyn photo.

Latest study suggests giant trees can persist along central coast, at least for a while

Staff Report

Redwood trees in California face an uncertain climate future, but some of the latest research suggests they’ll be able to persist in the coastal mountains south of San Francisco. And suitable climate conditions for the giant trees may expand northward in to Oregon, according to a new study published in Global Change Biology.

The research focused on the central California coast, where Redwoods are protected in a series of 14 parks, including the Santa Cruz Mountains, Julia Pfeiffer Burns State Park south of Carmel, and Garrapata State Park between Carmel and Big Sur on the Monterey coast. Continue reading

Forests and CO2 — It’s complicated!

One of the few lodgepole seedlings to survive the industrial clearcutting on the north shore of the Frisco Peninsula.

Climate models may be overestimating the carbon-capturing capacity of forests. @bberwyn photo.

Loss of nitrogen a key factor in forest equation

Staff Report

Forests may grow faster as atmospheric CO2 increases, but that doesn’t mean they’ll absorb more of the heat-trapping gas. Instead, a shortage of nitrogen means plants won’t be able to fix as much carbon as projected by some climate models.

“Forests take up carbon from the atmosphere, but in order for the plants to fix the carbon, it requires a certain amount of nitrogen,” said researchers Prasanth  who took a close look at the chemistry of secondary forests that are regrowing after deforestation, wood harvest and fires.

“If that ratio of carbon to nitrogen isn’t right, even if you add many times more carbon than it gets currently, the forests cannot absorb the extra carbon,” Meiyappan said. Continue reading

Global summit highlights crucial role of forests in climate change, economic development efforts

Slowing deforestation requires integration of forest planning with other sectors like water and agriculture

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Global forests are a key resource that require more attention, experts said at the UN’s forest congress in Durban, South Africa. @bberwyn photo.

Staff Report

Management of the world’s forests must be integrated with other land use planning efforts in order to address the root causes of deforestation, and forests should be recognized as “more than trees,” experts concluded at last week’s World Forestry Congress in Durban, South Africa.

With good management, forests have great potential to help end hunger, increasing wealth and improving livelihoods in developing countries, as well as in slowing climate change, the delegates from around the world said in the session-ending Durban Declaration.

Continue reading

Wet spring and summer may dampen fall colors

Some aspens and cottonwoods have been hit by leaf blight

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An aspen stand in the Lower Blue Valley, north of Silverthorne, Colorado.

Staff Report

FRISCO — Colorado’s wet spring and summer dampened the fire danger and kept the state nearly drought-free, but there may be a down side. Some of the state’s aspens and cottonwoods may not be at their most brilliant this autumn, after leaf-spot diseases afflicted some stands in northern Colorado and along the Front Range.

The Colorado State Forest Service says tree experts have been seeing an unusually high degree of leaf blight spreading as far south as Aspen, the Collegiate Peaks and Colorado Springs.

At least two fungal diseases are to blame for the leaves now showing significant spotting or dark splotches. Marssonina leaf spot is caused by the Marssonina fungus and is the most common leaf disease of aspen and cottonwoods in Colorado. The disease can be identified by the presence of dark brown spots or flecks on leaves, which can then fuse into large, black splotches on severely infected leaves. Continue reading

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