Pine trees one of biggest contributors to air pollution: pine gases chemically transformed by free radicals

Science Daily: Pine trees are one of the biggest contributors to air pollution. They give off gases that react with airborne chemicals -- many of which are produced by human activity -- creating tiny, invisible particles that muddy the air. New research from a team led by Carnegie Mellon University's Neil Donahue shows that the biogenic particles formed from pine tree emissions are much more chemically interesting and dynamic than previously thought. The study provides the first experimental evidence that such compounds are chemically transformed by free radicals, the same compounds that age our skin, after they are first formed in the atmosphere.

These findings, published in the Proceedings of the National Academy of Sciences, can help make climate and air quality prediction models more accurate, and enable regulatory agencies to make more effective decisions as they consider strategies for improving air quality.

"We have been able to show conclusively that biogenics are chemically transformed in the atmosphere. They're not just static. They keep going, they keep changing and they keep growing," said Donahue, professor of chemistry, chemical engineering, engineering and public policy, and director of Carnegie Mellon's Center for Atmospheric Particle Studies. "Quite a few atmospheric models, which are commonly used to inform research and policy, have been assuming that that doesn't happen. What we really need to have in the models is an accurate representation of what's really going on in the atmosphere, and that's what this lets us do."

The air that we breathe is chock-full of particles called aerosols. These tiny liquid or solid particles come from hundreds of sources including trees, volcanoes, cars, trucks and wood fires. The small particles influence cloud formation and rainfall, and affect climate and human health. In the United States each year, 50,000 premature deaths from heart and lung disease are attributable to excess concentrations of aerosols, especially particles less than 2.5 micrometers in diameter.

"There's a very, very strong body of data that establishes that fine particles in the air we breathe have a significant bad effect on people. What is less well understood is how the size and chemical composition of those particles influences that effect," Donahue said....

A pine near Lake Tahoe, shot by Brewbooks at Flickr, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Climate change killing the lodgepole pines of North America

Terra Daily: Lodgepole pine, a hardy tree species that can thrive in cold temperatures and plays a key role in many western ecosystems, is already shrinking in range as a result of climate change - and may almost disappear from most of the Pacific Northwest by 2080, a new study concludes. Including Canada, where it is actually projected to increase in some places, lodgepole pine is expected to be able to survive in only 17 percent of its current range in the western parts of North America.

The research, just published in the journal Climatic Change, was done by scientists from the College of Forestry at Oregon State University and the Department of Forest Resource Management at the University of British Columbia. It was based on an analysis of 12,600 sites across a broad geographic range.

Lodgepole pine ecosystems occupy large areas following major fires where extreme cold temperatures, poor soils and heavy, branch-breaking snows make it difficult for other tree species to compete. This includes large parts of higher elevation sites in Oregon, Washington, the Rocky Mountains and western Canada. Yellowstone National Park is dominated by this tree species.

However, warming temperatures, less winter precipitation, earlier loss of snowpack and more summer drought already appear to be affecting the range of lodgepole pine, at the same time increasing the infestations of bark beetles that attack this tree species….

Ten years after the 1988 Yellowstone fires, Lodgepole pine forests are firmly reestablished, image taken by Jim Peaco, September 1989, from the Yellowstone Digital Slide Files archives which are all in the public domain