Featured Research

from universities, journals, and other organizations

Western U.S. Forests At Risk: Complex Dynamics Underlie Bark Beetle Eruptions

Date:
June 6, 2008
Source:
American Institute of Biological Sciences
Summary:
Biological interactions involving fungi as well as trees and competing insects drive bark beetle outbreaks. The processes are sensitive to a forest's condition and the local climate, but prediction is difficult because the processes turn on multiple critical thresholds. Nonetheless, human activities are making outbreaks more extensive and frequent. Climate change and biological processes at large and small scales drive outbreaks now killing forests in the American West.

Examination of trees with bark beetles, such as the mountain pine beetle, usually reveals the presence of pitch tubes. Pitch tubes are made when female beetles bore into the tree.
Credit: U.S. Forest Service

Biological interactions involving fungi as well as trees and competing insects drive bark beetle outbreaks. The processes are sensitive to a forest's condition and the local climate, but prediction is difficult because the processes turn on multiple critical thresholds.

Related Articles


Nonetheless, human activities are making outbreaks more extensive and frequent. Climate change and biological processes at large and small scales drive outbreaks now killing forests in the American West.

Forest management that favors single tree species and climate change are just two of the critical factors making forests throughout western North America more susceptible to infestation by bark beetles, according to an article published in the June 2008 BioScience.

Bark beetle epidemics have become more extensive and frequent in recent years as winter temperatures have risen, and an eruption of mountain pine beetles is currently devastating lodgepole pines throughout the mountainous West.

The article, by Kenneth F. Raffa of the University of Wisconsin at Madison and colleagues at Colorado State University, the University of Idaho, and the US and Canadian Forest Services, stresses the complexity of the biological processes that determine when a bark beetle eruption will occur. When beetles bore through a tree's bark, they release pheromones that summon other beetles to join the offensive.

Trees counter attacks by exuding resin that can kill the invaders, but if too many beetles attack a weak tree, its defenses fail. The beetles then reproduce within its living tissues, with the help of colonizing fungi, and the tree is doomed. The condition and spacing of nearby trees and the local climate affect whether the beetle progeny released after a successful attack sustain an epidemic--which can kill a high proportion of the trees in an area and so alter the landscape for decades.

Because many of the processes in an epidemic operate at different scales and turn on critical thresholds, prediction is a challenge. It is nonetheless clear that human activities can exacerbate bark beetle eruptions, which cause major economic losses and reduce forests' ability to absorb carbon from the atmosphere.


Story Source:

The above story is based on materials provided by American Institute of Biological Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. Raffa et al. Cross-scale Drivers of Natural Disturbances Prone to Anthropogenic Amplification: The Dynamics of Bark Beetle Eruptions. BioScience, 2008; 58 (6): 501 DOI: 10.1641/B580607

Cite This Page:

American Institute of Biological Sciences. "Western U.S. Forests At Risk: Complex Dynamics Underlie Bark Beetle Eruptions." ScienceDaily. ScienceDaily, 6 June 2008. <www.sciencedaily.com/releases/2008/06/080602075818.htm>.
American Institute of Biological Sciences. (2008, June 6). Western U.S. Forests At Risk: Complex Dynamics Underlie Bark Beetle Eruptions. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2008/06/080602075818.htm
American Institute of Biological Sciences. "Western U.S. Forests At Risk: Complex Dynamics Underlie Bark Beetle Eruptions." ScienceDaily. www.sciencedaily.com/releases/2008/06/080602075818.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Antarctic Sea Ice Mystery Thickens... Literally

Antarctic Sea Ice Mystery Thickens... Literally

Newsy (Nov. 25, 2014) — Antarctic sea ice isn't only expanding, it's thicker than previously thought, and scientists aren't sure exactly why. Video provided by Newsy
Powered by NewsLook.com
3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) — A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) — A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Yellow-Spotted Turtles Rescued from Trafficking

Yellow-Spotted Turtles Rescued from Trafficking

Reuters - Light News Video Online (Nov. 24, 2014) — Hundreds of Amazon River turtles released into the wild in Peru. Sharon Reich reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins