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 “Aerial forest surveys track continued spread of spruce beetles across Colorado forests”→
Scientists report success in treating seedlings with mushroom spores
By Bob Berwyn
FRISCO — High-elevation whitebark pines are under the gun in the northern Rockies. White pine blister rust, an invasive fungus, and pine beetles have combined to drive the species toward extinction.
But scientists trying to recover the species say that a humble mushroom could help their efforts. A three-year experiment shows a 10 to 15 percent increase in the survival rate of whitebark pine seedlings when Siberian slippery jack spores are injected into the soil around them. The injection takes place in nurseries before the seedlings are transplanted in the mountains. Continue reading “Humble fungi may aid whitebark pine recovery”→
Study shows no clear link between beetle-kill and ecological severity of western wildfires
FRISCO — For all their frenzied tree-killing during the past 10 years, mountain pine beetles haven’t been a big factor in the ecological severity of wildfires in the West, a team of university scientists said this week.
Weather and topography are the main factors in determining how much damage a wildfire does to forest ecosystems, according to the researchers with the University of Wisconsin-Madison and the Washington State Department of Natural Resources.
Science sometimes missing from forest management policies
By Bob Berwyn
FRISCO — While politicians and policy makers continue to conflate a number of complex forest health and wildfire issues, a new study suggests there’s little evidence supporting the idea that logging helps to control or contain the spread of tree-killing pine beetles.
Nobody disputes the need to clear trees, brush and other fuels from around homes in fire-prone forest areas, but some lawmakers who should know better have been pushing for more logging under the guise of restoring forest health and as an antidote to insect infestations.
The idea that speedy approval of logging projects could help restore forest health was also used as a basis for short-cutting environmental reviews for logging projects, possibly resulting in negative long-term environmental impacts in forests.
Spruce beetle infestation grows in southwestern mountains
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.
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 “Pointing the way to pine beetle control, but at what cost?”→