Shannon Sawyer

September 29, 2008

In recent years, the Rocky Mountain region of North America has been faced with an increasingly frustrating infestation of mountain pine beetles. The beetle has been decimating lodgepole pine populations, leaving millions of acres of dead trees in its wake throughout the west. According to experts, every large, mature lodgepole pine forest in Colorado and southern Wyoming will be dead within three to five years.

Perhaps most at stake are the state's water supplies. A lack of soil cover and the potential for forest fires as the dying trees dry out could leave reservoirs and rivers clogged with sediment more likely to pour off the landscape. Recreation, too, is jeopardized, as campers and skiers are faced with spending their vacation time amid red-needled trees, or those with no needles at all. Backcountry hikers will need to be more cautious about falling trees and mountain town economies could also be hurt by a browning backdrop less alluring to visitors.

Although the main concerns over the dead and dying forests include disruption of the timber industry, an increased risk of wildfires, and impacts on tourism, a new concern has recently emerged. Researchers are predicting that the infestation may adversely affect weather patterns and affect the air quality in areas that are particularly hard-hit.

Researchers are not yet able to determine whether the changes to western forests will result in an increase or decrease of particles of ozone. They are also unsure exactly how the changes will affect the weather. Scientists do know that when beetles first attack a tree, the tree emits large concentrations of volatile organic compounds, so particle and ozone concentrations may rise initially. These particles can form the nucleus for raindrops and smog. In addition to affecting the weather, elevated concentrations of small particles can also increase incidence of respiratory and heart problems.

The particles emitted by the dying trees are not the only concern. The destruction of large swaths of forest affects the amount of sunlight that reaches the forest floor, drying out the understory and decreasing the cooling effect provided by the release of water from vegetation. The loss of vegetation can also affect local weather in that it can change the absorption and reflection of sunlight in some areas. Living forests soak up carbon dioxide, while dead ones release it, potentially contributing to warming.

Experts seem to agree that efforts to stop or even slow the infestation would be unsuccessful. Instead, local communities, landowners and the Forest Service can only target pockets where dead forests would pose a fire risk to homes, towns and water supplies. It is also thought that Forestry practices, such as thinning thick stands of pure species of trees, can also slow the spread in the future.

Sources:

Jessica Marshall, Beetle Invasion Seen Changing Weather, http://www.msnbc.msn.com/id/26872373/wid/18298287/ (last visited Sept. 25, 2008).

Todd Hartman, Deaths of Trees Catastrophic, Rocky Mountain News, Jan. 5, 2008, available at http://www.rockymountainnews.com/news/2008/jan/15/beetle-infestation-get-much-worse/ (last visited Sept. 25, 2008).

Randolph E. Schmid, Study Looks at Beetles' Effect on Weather, Seattle Post-Intelligencer, Sept. 24, 2008, available at http://seattlepi.nwsource.com/national/1501ap_sci_beetles_weather.html (last visited Sept. 25, 2008).

Howard Pankratz, Beetle Scourge Goes From Bad to Worse, Denver Post, Jan. 15, 2008, available at http://www.denverpost.com/ci_7972146 (last visited Sept. 25, 2008).