Bark beetles take bite out of air quality, study says
It appears that bark beetles are attacking more than just the trees.
Research conducted outside Steamboat Springs has found that the beetles that have decimated pine and spruce forests throughout the western United States have also inadvertently contributed to the air quality problems that plague much of the region.
Lodgepole pines infested with bark beetles can release 5 to 20 times the amount of gases that can contribute to haze and airborne particulate matter than non-infested trees, according to a study published last week in the journal Environmental Science & Technology.
“When thinking about bark beetle infestations maybe we need to think about not just the forest but what is it going to do to air quality and climate change,” said Kara Huff Hartz, one of the study’s authors, from Southern Illinois University Carbondale, where she is an assistant professor.
The gases released by the infested trees, called volatile organic compounds, can contribute to the formation of particulate matter air pollution, which can cause human health problems and affect climate change.
Why exactly the infestations result in higher emissions of these volatile organic compounds is still not clear, said Huff Hartz.
One of several possibilities is that when the beetles bore into the bark they are creating a sort of pipeline for the compounds in the tree’s resin to escape into the atmosphere, she said.
Once those compounds are out, a complicated chain of chemical reactions follows that eventually results in the haze- and pollution-causing particles.
To reach this conclusion, researchers at the Storm Peak Laboratory above Steamboat Springs’ ski slopes collected air samples from both beetle-infested and healthy trees in the area, before sending them to Huff Hartz for analysis.
The study is the first to examine the relationship between air quality and mountain pine beetle infestations, according to Gannet Hallar, director of the Steamboat lab, who also worked on the study.
She says they now hope to incorporate their data into a model that would look at the relationship between bark beetle infestations and air quality for the whole western region.
“We showed the impacts at the individual tree level. Now, we will look at the region,” she said.
Researchers have also examined the relationship between bark beetles that target spruce trees and air quality. Huff Hartz said that research also turned up an increase in emissions of volatile organic compounds, though of a different variety and not as severe. That research has not been published yet.