As the Intermountain spring gains momentum and outdoor enthusiasts head for the region’s national forests, they’ll encounter shriveled, rust-colored sentinels in the wake of continued ravages by tiny insects.

“Residents of Utah and other western states are noticing more and more dead trees in local forests and wondering, ‘What’s going on?’” says Barbara Bentz, research entomologist with Logan’s U.S. Forest Service Rocky Mountain Research Station.

 

Bentz, who serves as an adjunct associate professor in Utah State University’s Department of Wildland Resources, helped to organize a 2005 symposium of scientists from throughout North America to explore the increasing frequency of bark beetle outbreaks in western forests. With writer Hannah Nordhaus, she compiled the group’s observations into a concise, easy-to-read text aimed at non-scientific audiences. The 44-page booklet, Bark Beetle Outbreaks in North America: Causes and Consequences, was recently released by University of Utah Press.   

 

“Our aim with the book was to present scientific information in a form that lay people could understand,” Bentz says.

 

Featuring color photos and graphs, the book details varied species of bark beetles causing the infestations, along with descriptions of climate change, forestry management practices, human influences and disturbances that could be accelerating the outbreaks.

 

“We believe that two major factors are responsible for increased beetle infestations,” Bentz says. “One is climate change with associated shifts in precipitation and temperature that influence both the beetles and their host trees. The other is a legacy of forestry management practices during the past 100 years that have created forest landscapes throughout western North America that are highly susceptible to bark beetle outbreaks.”

 

Bark beetles are native insects of western North America and Bentz cautions that little is known about their impact on regional forests prior to the close of the 19th century. 

 

“We ask, ‘Are the current outbreaks unprecedented?’ and, because we don’t have a long history of recorded data, that’s hard to answer,” she says. “But based on the information we do have, it appears today’s outbreaks are longer in duration and intensity and occurring on a larger geographic scale than those of the past 150 years.”

 

USU scientists who contributed to the book include Trustee Professor Jim MacMahon, director of the USU Ecology Center; Jim Powell, professor in the Department of Mathematics and Statistics; Mike White, associate professor in the Department of Watershed Sciences and Jesse Logan, former USFS research entomologist, now retired, who served as an adjunct faculty member in the Department of Wildland Resources.

 

The publication, funded by the USDA Forest Service Rapid Science Assessment Team, is available for purchase on-line from University of Utah Press.

 

 

Contact: Barbara Bentz, (435) 755-3577, bbentz@fs.ed.us
Writer: Mary-Ann Muffoletto, (435) 797-3517, maryann.muffoletto@usu.edu

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