‘We are seeing the initiation of a retreat of forests to higher elevations’
Global warming is likely one of the main factors that’s preventing some Colorado forests from regenerating after wildfires.
When they started studying eight wildfire sites that burned across 162,000 acres of low-elevation forests along the Front Range, University of Colorado Boulder researchers said they expected to see young trees popping up all over the place, but that’s not what they found.
There were no seedlings at all in 59 percent of the study plots and 83 percent showed a very low density of seedlings. Future warming and associated drought may hinder significant further recovery, the researchers concluded. Only 2 to 38 percent of plots surveyed, depending on the fire site, were considered stocked, or on their way to recovery. Continue reading “Global warming hampers post-fire forest regrowth in Colorado”→
Spruce beetles continued to expand in Colorado in 2016, at least in part due to global warming and drought, as well as the density of old-growth spruce forests.
In all, spruce beetles were active across 350,000 acres of higher-elevation stands of Engelmann spruce statewide, including about 136,000 acres of new activity, causing widespread tree mortality, according to the results of the latest aerial surveys conducted by the U.S. Forest Service and the Colorado State Forest Service. Since 1996, spruce beetle outbreaks have caused tree mortality on more than 1.7 million acres in Colorado. Continue reading “Spruce beetles still on the march in Colorado”→
New satellite data helps track photosynthesis in evergreens
Despite the huge importance of forests in the global carbon cycle, researchers still aren’t exactly certain how they will respond to climate change. But that could soon change thanks to satellite sensors that can track photosynthesis in evergreen forests by monitoring slight color shifts.
The new information could help assess the health of northern forests over time, showing how they are responding to global warming. Photosynthesis is easy to track in deciduous trees — when leaves bud or turn yellow and fall off. But until recently, it had been impossible to detect in evergreen conifers on a large scale. Continue reading “How will boreal forests respond to global warming?”→
Commercially valuable tree stands take hit in Pacific Northwest
Global warming may be a factor in the spread of a fungus affecting valuable Douglas fir forests in the Pacific Northwest. Needle cast disease has recently spread across 590,000 acres in Oregon, quadrupling since the start of surveys in 1996. The annual economic loss has been estimated at $128 million.
“The correlation between disease severity and climate factors, such as spring moisture and warm winter temperatures, raises the question of a link between disease expansion and climate change,” said researcher Gabriela Ritokova. “Those factors, in combination with lots of Douglas fir and with large springtime fungal spore production, have us where we are now.” Continue reading “Climate change may be factor in spread of tree fungus”→
Study says disastrous tipping points could be reached by 2050
Forests of the future may not be able to remove heat-trapping CO2 from the atmosphere as effectively as previously thought, scientists said in a new study that’s based on an extensive analysis of tree ring data from the past.
“We utilized a network of more than two million tree-ring observations spanning North America. Tree-rings provide a record into how trees that grow in different climates respond to changes in temperature and rainfall,” said Brian Enquist, a professor in the UA’s Department of Ecology and Evolutionary Biology and a fellow of the Aspen Center for Environmental Studies in Aspen, Colorado.
The research challenges assumptions about how forests will respond to warmer average temperatures, increased greenhouse gas emissions, and shifting rainfall patterns. It also suggests that the warming climate already is rapidly pushing many forests towards an ecological tipping point, which may be reached as early as 2050, Exposure to unprecedented temperatures hampers tree growth and makes them susceptible to other stress factors. Continue reading “Forests may not benefit from rising CO2 levels”→
Climate change is wiping out forests on a staggering scale
California’s multiyear drought killed even more trees than previously thought, the U.S. Forest Service announced this week. Aerial and ground surveys show that 26 million trees across six counties in Southern California died, in addition to the 40 million trees that died statewide from 2010 to October 2015. Four years of drought, high temperatures and an outbreak of tree-killing bark beetles all contributed the historic levels of tree die-off, the agency said.
Around the same time, pine beetles started spreading across northern Colorado, parts of Wyoming and North Dakota, ultimately killing millions of acres of forest. And just as the pine beetle infestation waned, a spruce beetle outbreak in southern Colorado started to spread. Since 1996, spruce beetles have killed trees across about 1.5 million acres of forest.
New study focuses on drought-stricken California forests
A rising tide of insect infestations, tree mortality and wildfires — all caused by global warming — has resulted in political pressure for more logging in U.S. Forests, but there’s plenty of research showing that cutting down trees doesn’t do much good and can even increase the fire danger.