Climate to Push Forest-eating Beetles to Northern US, Canada, Scientists Predict

Forests in the northeastern United States and southern Canada could be ravaged by tree-killing beetles in coming decades as a warming climate expands the pest’s habitat, a study has found.

Over the next 60 years, southern pine beetles could infest forests in new areas of the United States and Canada, disrupting industries and ecosystems alike, it said.

Warmer winter nights allow spread

The red-brown insects, the size of a grain of rice, known to feast on pine-tree bark, has typically only thrived in the hotter climate of Central America and the southeastern United States.

But in recent years warmer than usual winter nights have allowed it to survive the cold months and spread as far north as the U.S. state of New York. The coldest winter night has warmed by 6 to 7 degrees Fahrenheit (3 to 4 degrees Celsius) over the past 50 years in various parts of the United States, the study’s authors said.

Using computer-based climate models, they predicted the beetles should gradually march north along the Atlantic coast, infesting forests including in the U.S. states of Maine and Ohio all the way to Canada’s Nova Scotia.

Pest moves fast

By 2080, the pest should proliferate to red — and jack-pine forests in a 270,000 square miles (700,000 square km) area of the United States and Canada — roughly the size of Afghanistan, the researchers wrote in Nature Climate Change.

That would not only upend ecosystems, but also disrupt several key industries “in already struggling rural areas,” said lead author Corey Lesk, a researcher at Columbia University in New York.

“Residents of these regions could see a direct hit to their pocketbooks,” he told the Thomson Reuters Foundation on Tuesday in a phone interview.

Infestations costly to timber industry

Where the southern pine beetle has struck in the past, timber industries have been hard hit.

Infestations of pine beetles have cost an estimated $100 million a year in timber losses from 1990 to 2004 in the southeastern United States, according to the U.S. Forest Service.

Thousands of adult beetles can kill a tree in two to four months as the insects carve S-shaped tunnels under the bark, depriving their host of needed nutrients.

The tourism industry would also likely suffer, said Lesk, with the potential destruction of iconic forests including the Pine Barrens of New Jersey and Long Island.

Europe faces same problem

In Europe, previous research has shown that bark beetles have similarly been chewing through pine and spruce trees in forests from the Swiss Alps to Belarus alongside temperature increases.

Land managers have found the best way to fight off bark beetles has been thinning high-density forests and cutting out infested trees, though with limited success, the researchers said.

“The key question is whether those strategies would be able to keep up with rapid advance of the pest into regions with little or no experience managing it,” Lesk said.


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