Latest survey tallies more than 100 milion dead trees
California’s long-term drought has claimed another 36 million trees, the U.S. Forest Service said this week, announcing the results of a new aerial survey. Since 2010, more than 100 million trees have died across 7.7 million acres, the agency said.
The die-off intensified in 2016, after four years of drought, with mortality increasing 100 percent. Millions of additional trees are weakened and expected to die in the coming months and years. Forest Service leaders once again emphasized that their ability to address safety issues linked with dead trees has been severely hampered by climate change and limited resources.
Study suggests carbon uptake by forests has doubled since the 1950s
Scientists say they’ve place yet another piece in the complex global plant-carbon cycle, with a new study suggested that atmospheric CO2 levels have plateaued in recent years because forests and grasslands are removing more of the heat-trapping gas. The research was led by a scientist with the Department of Energy’s Lawrence Berkeley National Laboratory .
All mountain ranges have to end somewhere, and for the Alps, the eastern terminus is the Wienerwald, a chain of rolling, low-slung hills on the outskirts of Vienna that drop down to the Danube Basin along a tectonic escarpment marked by a series of hot- and cold-water springs. It’s a geological and biological transition zone, where the rather moist and cool climate of northwestern Europe gives way to the drier regime of the Pannonian Basin to the southeast, including the Hungarian Puszta. Continue reading “Sunday set: Wienerwald”→
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?”→
Danube Pano from Aggstein Castle looking across at Willendorf.
Most travelers have heard of the Wachau region. The fertile hillsides along the Danube River have long been designated as a World Heritage region for its cultural and natural landscapes. But just across the river is another slice of forest, the Dunkelsteinerwald, that’s not quite as famous but just as beautiful. On a mid-October weekend, we hiked from the pilgrimage town of Maria Langegg up the restored Aggstein Castle, which was built in the 12th century. Like many others along the Danube, the castle was an outpost for charging toll to passing ships, a payment made in exchange for maintaining the paths along the shore that were used to tow ships upstream. But the area was inhabited long before that, with signs of civilization dating back to the Celtic era — and long before. Just across the river, construction workers in 1908 unearthed the famed Venus of Willendorf, a prehistoric fertility figurine dating back to about 25,000 BC.
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”→