By Dylan J. Darling • The Bulletin

Blending satellite images, human-drawn maps and on-the-ground inventories gives forest managers a better handle on two of the most common insect outbreaks around the West, according to recent research released by Oregon State University.

The new method results in detailed maps showing where the mountain pine beetle and western spruce budworm have been and where they are spreading, said Robert Kennedy, an assistant professor in OSU’s College of Earth, Ocean and Atmospheric Sciences.

“Knowing where things are happening allows people to do management better,” Kennedy said.

Since the late 1940s, forest managers have relied upon aerial surveys, during which people would draw maps of insect outbreaks from the air, to determine where the insects were having an impact. These maps were an estimate of the outbreaks, and Kennedy said adding satellite images, old and new, and data gathered in the woods give a clearer picture of an outbreak.

Both insects experience cyclical outbreaks, which, year to year, can affect millions of acres of forest.

The beetle and the budworm have a taste for different trees. The mountain pine beetle mainly attacks lodgepole and ponderosa pines, while the western spruce budworm defoliates, or takes the needles off, spruce, Douglas fir and true firs.

“Mortality from bark beetles is only the beginning of long-term change,” Helen Maffei, a pathologist with the Deschutes National Forest in Bend, said in a news release about the research. “Dead trees fall and decay, and forest regrowth begins and continues over many decades. This new technique can help us understand not only how insect outbreaks are initiated and spread but also address … ‘What comes next?’ It can help us better understand the process of recovery.”

The last big mountain pine beetle outbreaks in the Northwest were in the 1980s and 2000s, said Garrett Meigs, whose graduate studies focused on the new mapping method while he was at OSU. Meigs is now a post-doctoral researcher at the University of Vermont. The last big spruce budworm outbreaks in the eastern Cascades were in the 1980s and early 1990s.

Dual outbreaks of the insects hit Santiam Pass decades ago, leaving large swathes of dead trees, he said.

The new mapping method — which Kennedy and Meigs detailed earlier this month in an article for Forest Ecology and Management — would not only allow forest managers to better understand the extent of past outbreaks but also anticipate future outbreaks.

“Until this point, aerial surveys have been the go-to,” he said.

Building on a partnership between OSU and Google, Kennedy is working with the company to possibly make satellite data about the insects available on Google Earth Engine, a cloud computing platform for processing images captured by satellites and data collected on Earth.

— Reporter: 541-617-7812, ddarling@bendbulletin.com

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