Global warming likely to slow forest regrowth after fires

Warming climate increases moisture stress, making it tougher for seedlings to take hold and grow

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Global warming is likely to be a factor in forest regeneration after wildfires. This is the East Peak Fire, burning in June, 2013, on the east slopes of the Spanish Peaks above Walsenburg, Colorado. Photo courtesy Don Degman/Inciweb.

By Summit Voice

FRISCO — A warming climate in the West may slow or, or even stop, conifer forest regeneration in drier, low-elevation areas after big forest fires. In some cases, they may never grow back, instead converting to shrub and grasslands, according a new Oregon State University study.

The researchers concluded that moisture stress is a key limitation for conifer regeneration following stand-replacing wildfire. Both wildfires and more dryness are projected for big parts of the West by most climate models. This will make post-fire recovery on dry sites slow and uncertain. If forests are desired in these locations, more aggressive attempts at reforestation may be needed, they said. Continue reading

Opinion: Letter from western governors a misguided, muddled attempt to hijack national forest management

Let science, not politics, guide forest management

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One man’s healthy forest is another man’s tree farm. Bob Berwyn photo.

By Bob Berwyn

SUMMIT COUNTY — Flying in the face of science, the Western Governors’ Association last week called on the U.S. Forest Service to do more logging in an effort to promote forest health.

The letter, signed by Colorado Gov. John Hickenlooper and Utah Gov. Gary. R. Herbert, also seems to suggest that privatizing some activities on publicly owned national forest lands could help address what they called a forest health crisis — without a single mention of global warming or the crucial restorative role of wildfires in forest ecosystems. Continue reading

Environment: Can forest health be legislated?

Proposed Senate bill would require widespread national forest logging

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Healthy undergrowth and lodgepole regeneration in an unlogged stand of beetle-killed lodgepole pines near Frisco, Colorado. Bob Berwyn photo.

Salvage logging in a stand of beetle-killed lodgepole pines in Frisco, Colorado. Bob Berwyn photo.

Salvage logging in a stand of beetle-killed lodgepole pines in Frisco, Colorado. Bob Berwyn photo.

*This story has been corrected to include Sen. Michael Bennet as the primary author of the proposed bill. That information was left out of the previous version due to an editing error.

By Summit Voice

SUMMIT COUNTY — Federal land managers could get wider authority for more backcountry logging under a new bill proposed in the U.S. Senate by Michael Bennet (D-CO), along with co-sponsors Mark Udall (D-CO), Ron Wyden (D-OR), and Max Baucus (D-MT).

The National Forest Insect and Disease Treatment Act is being pitched as a way to   help Forest Service treat insect and disease epidemics and promote overall forest health. As drafted, it directs the agency to treat threatened watersheds while prioritizing preservation of old-growth and large trees when possible. Continue reading

Forests: Canadian scientists decode pine beetle genome

Mountain Pine Beetle. Photo by: Ward Strong, B.C. Ministry of Forests, Lands, and Natural Resource Operations

Mountain Pine Beetle. Photo courtesy Ward Strong, B.C. Ministry of Forests, Lands, and Natural Resource Operations.

Findings may help forest managers control outbreaks

By Summit Voice

SUMMIT COUNTY — Scientists who recently completed decoding the pine beetle genome say their findings could help forest managers develop ways to manage the epidemic in the future.

“We know a lot about what the beetles do,” said Christopher Keeling, a research associate at Canada’s Michael Smith Laboratories. “But without the genome, we don’t know exactly how they do it.” Continue reading

Colorado gets new state forester

Mike Lester says Colorado forests face ‘extraordinary changes’

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Colorado’s aspen forests may see more die-offs as a result of last summer’s drought.

By Summit Voice

SUMMIT COUNTY — Colorado’s new state forester and director of the Colorado State Forest Service may be moving here from Pennsylvania, but his forestry roots are pure Colorado.

Mike Lester is a CSU alumnus and spent time with the Rocky Mountain Forest and Range Experiment Station. He currently serves as assistant state forester for the Pennsylvania Bureau of Forestry, a position in which he is responsible for more than 300 staff, manages 2 million acres of state forest land, oversees the Pennsylvania State nursery manager, and manages a silviculture program that yields $25 million in annual revenues.

As Colorado  state forester, Lester is responsible for the protection of Colorado’s forest resources; ensuring forestry education, outreach and technical assistance to private landowners; and carrying out the duties of the Division of Forestry within the Colorado Department of Natural Resources. Continue reading

Study: Global warming reduces piñon pine seed formation

Absence of late-summer cold snaps may be the key factor

Piñon pines growing in the badlands of southeastern Colorado. Bob Berwyn photo.

Piñon pines growing in the badlands of southeastern Colorado. Bob Berwyn photo.

By Summit Voice

SUMMIT COUNTY — Piñon pines, a key food source for wildlife in Southwest ecosystems, are producing 40 percent fewer pine cones than just a few decades ago, and global warming may be the culprit, according to CU-Boulder researchers who tracked seed production at nine study sites in New Mexico and northwestern Oklahoma.

The decline in seed production could have profound implications for regional ecosystems, said CU-Boulder doctoral student Miranda Redmond, who led the study. The biggest declines in pinyon pine seed cone reproduction were at the higher elevation research sites, which are experiencing more dramatic warming relative to lower elevations, Redmond said.

“We are finding significant declines in pinyon pine cone production at many of our study sites,” said Redmond. “The biggest declines in cone production we measured were in areas with greater increases in temperatures over the past several decades during the March to October growing season.” Continue reading

Climate, not beetle-kill, the biggest factor in wildfire equation

New research could help inform forest management

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Clear-cutting beetle-killed lodgepole stands has left remaining trees susceptible to blow-down.

By Bob Berwyn

SUMMIT COUNTY — While many forest managers and politicians are still broad-brushing the wildfire danger associated with beetle-killed forests, a new report once again suggests that the fire hazard linked with beetle-kill has been overstated.

After reviewing some of the latest research, the authors of the paper concluded that, “To date, the majority of studies have found no increase in fire occurrence, extent, or severity following outbreaks of spruce beetle … and mountain pine beetle … in Colorado, Wyoming, and other areas.”

Instead, there’s more and more evidence that climate — specifically global warming — is the main factor.

“The main message is that, if we want to understand fire dynamics, we need to understand the ultimate cause and effect,” said CSU professor Barry Noon, one of the coauthors. “The real drivers are drought conditions, temperatures and precipitation. That highlights the human factor in the equation,” Noon said, referring to global warming driven by greenhouse gas emissions. “That may make us uncomfortable, but the evidence just keeps accumulating all the time,” he said. Continue reading

Pointing the way to pine beetle control, but at what cost?

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Pine beetle-killed trees in Summit County, Colorado.

Dartmouth scientists study pine beetle population dynamics

By Summit Voice

SUMMIT COUNTY — Dartmouth scientists say they may have found a pathway to keeping pine beetles in check, showing that their populations fluctuate between extremes, with no middle ground.

“That is different from most species, such as deer, warblers and swallowtail butterflies, whose populations tend to be regular around some average abundance based on food, weather, and other external factors,” said Matt Ayres, a professor in the Department of Biological Sciences at Dartmouth and senior author on the paper. “They don’t appear and disappear in cycles. Rather, they exist in two stable equilibrium states—one of high abundance and the other of scarcity.”

Once the population pendulum swings toward the high end, it won’t quickly or easily swing back, Ayres explained.

According to the new study, forest managers might be able to keep pine beetle populations at the low end of the scale by boosting competitor and predator beetle populations — but they don’t address how that could affect the overall equilibrium of forest ecosystems, especially those where older trees need a change agent like bark beetles to spur regeneration. Continue reading

Colorado: Governor requests spending increases for education, wildfire mitigation and fracking studies

Colorado Gov. John Hickenlooper.

Colorado Gov. John Hickenlooper.

State ranks near the bottom for per-pupil funding

By Summit Voice

SUMMIT COUNTY — As Colorado’s budget picture continues to brighten, Gov. John Hickenlooper this week requested budget amendments that would boost spending on education and allocate funds to study environmental impacts of energy development and for forest health work.

The 2013-2014 budget will be the first in several years that includes more spending on education and without any big cuts. Overall, the state’s general fund is expected grow by about $.5 billion, from 7.6 billion to $8.1 billion.

State budget officials said Hickenlooper’s request fulfills his intent to spend increased revenue on education, public health, safety and infrastructure. Specifically, spending on k-12 education would increase by $12.8 million, boosting per-student funding to $6,607 dollars, up $228 from last year.

Only a handful of states spend less per pupil than Colorado, including Arizona, Nevada, Tennessee, Texas, Utah, North Carolina. See the rankings here. Top-ranked states like New York, Vermont and Connecticut spend about twice as much per student. Continue reading

Tree die-offs altering chemistry of forest ecosystems

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Eastern hemlock, courtesy Amherst University. Click on the image to learn more about the woolly adelgid.

Spread of tree pests linked with global warming

By Summit Voice

FRISCO — In research that could have implications for Colorado’s beetle-killed forests, scientists studying the die-off of hemlock trees documented how the loss of some species can lead to widespread ecosystem changes — sometimes to the benefit of other species.

“Our findings were unexpected,” said University of Illinois landscape and ecosystem ecologist Jennifer Fraterrigo. “We hypothesized that in this area of the southern Appalachians, where there is a lot of nitrogen available due to high rates of atmospheric nitrogen deposition, hemlock mortality would increase nitrogen leaching from the soil because the trees were no longer taking up that nitrogen, but we found the opposite. We found less nitrogen leaching from the soil because hardwood trees had compensated by increasing their productivity.”

The research is part of an effort to understand the impacts of exotic pests and pathogens, which are eliminating tree species one by one from forest ecosystems. In some cases, scientists can observe immediately how their loss affects the environment, whereas in other cases, creative puzzle solving and analysis reveal unexpected repercussions.

Throughout much of the eastern United States, a pest called the hemlock woolly adelgid has decimated hemlock tree populations. While researching how hemlock mortality affects nitrogen retention in the soil and vegetation, Fraterrigo noticed that other components of the ecosystem were changing.

“The hardwood trees were able to grow because, when the hemlock trees died, phosphorus was released and became available to the hardwood species in the area. The increase in available phosphorus stimulated the growth of existing hardwood trees, which then increased tree demand for nitrogen. As a result, we saw less nitrogen being leached from the soil. Without hemlock mortality, the hardwood trees could not take up the excess nitrogen in the soil because their growth was limited by a lack of phosphorus, Fraterrigo said.

“We believe chronically high nitrogen availability is actually driving the accumulation of phosphorus in vegetation and soil organic matter in this area. Without disturbance, however, the phosphorus stays locked up in these pools and is unavailable to support new growth,” Fraterrigo said.

Fraterrigo explained how the balance of nutrients operates in the environment.

“Nitrogen and phosphorus are among the most important elements for growth and carbon storage,” she said. “Plants fix carbon in the atmosphere, but if they don’t have enough of either of these elements, they’re limited as to how much carbon they can actually fix. It is the relative, not the absolute, amounts of nitrogen and phosphorus that limit growth and carbon storage.”

Although this would seem to be beneficial, at least for the hardwood industry, Fraterrigo said it’s important to look at the entire ecosystem and the ramifications of losing a species such as hemlock. Fraterrigo said hemlock is significant ecologically. “It’s a foundation species in this ecosystem. It provides structure because it’s an evergreen so wildlife depends on it year round for shelter. It also influences many biophysical processes, including those that affect ecosystem hydrology. Losing a species such as hemlock that is biologically active all year can alter stream flow, which could affect aquatic organisms,” she said.

Fraterrigo said that disturbances created by exotic pathogens and pests such as the hemlock woolly adelgid are increasing. “An introduced fungus is decimating oak populations in the West, and there’s the emerald ash borer in the Midwest. We need to study how the loss of tree species is affecting forest ecosystems,” she said.

The only places that hemlock stands can still be found in the Southeast are where an insecticide called Imidacloprid has been sprayed, Fraterrigo said. “But that’s just a temporary solution. You’d have to continue to apply it again and again in order to deter the hemlock woolly adelgid.”

The hemlock woolly adelgid is host specific, meaning it only infests hemlock trees. The aphid-like insect attaches itself to a needle, sucks the sap from it, and the tree dies.

“Although the hemlock woolly adelgid doesn’t do well in cooler climates, it is clearly affecting hemlock populations in the Northeast as well. It’s just taking longer to see the impact,” Fraterrigo said. “We’re seeing warmer temperatures at night across the nation and warmer winter temperatures in some places. Those two factors together could allow the insect to move slowly farther north.

“It’s difficult to anticipate how species loss will affect forest ecosystems,” she said. “Our research demonstrates that it is important to consider other drivers of global change, such as air pollution, to reveal ecosystem-level changes.”

Fraterrigo said she’d like to continue the work in the Great Smoky Mountain National Park, which has also lost hemlock and has even higher rates of atmospheric nitrogen deposition. “We’re curious if we’ll see similar changes in hardwood productivity and ecosystem nitrogen retention,” she said.

“Interactive effects of disturbance and nitrogen availability on phosphorus dynamics of southern Appalachian forests” was published in a 2012 issue of Biogeochemistry.

Impacts of hemlock loss on nitrogen retention vary with soil nitrogen availability in the southern Appalachian Mountains was published in a 2012 issue of Ecosystems. Other authors were Corinne Block, Jennifer Knoepp, and Katherine Elliott. Partial funding was provided by federal Hatch, the USDA Forest Service, and the National Science Foundation Long-Term Ecological Research Program.

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