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”→
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.
New analysis offers important forest health information
Colorful mushrooms that pop up in forests around the world are much more than decorative baubles. Much more than realized, fungi are key components of forest ecosystems, helping to regulate the carbon cycle and driving the nutrient exchange between soil and trees.
After taking a big-picture look at the water cycle, U.S. Forest Service researchers say global warming may decrease the amount of water produced by forests and grasslands across the country — even with increases in precipitation.
Global warming has killed half a billion trees across the U.S.
Scientists tracking massive forest die-offs say a new study may help forest managers learn how to predict which trees will succumb to global warming — and what the implications are for the global carbon balance.
“There are some common threads that we might be able to use to predict which species are going to be more vulnerable in the future,” said University of Utah biologist William Anderegg, explaining that recent tree-killing droughts in the western U.S. were marked more by elevated temperature than by a lack of rainfall.
“These widespread tree die-offs are a really early and visible sign of climate change already affecting our landscapes,” Anderegg said.
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”→
Large swaths of forest now seen as more vulnerable to future droughts
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 “California drought has damaged millions of trees”→