Study Finds the Southern Pine Beetle May be Chewing North

One of the world's most aggressive tree-killing insects could soon be heading north, due to warmer winters. A new study by the journal Nature Climate Change, warns that by 2020, the southern pine beetle could move deeper into the New York Metro area - and as far north as Nova Scotia.

Co-author Radley Horton, a researcher at Columbia University’s Lamont-Doherty Earth Observatory, says New Jersey will be a battleground for the tiny pine beetle, which is about 2-4 millimeters in length.

"It's been established for a very long time in the southeast U.S.," he explained. "But around the turn of the century, around the year 2000, we started to see it emerging in New Jersey and in the last 15 years it's been moving further and further north in the state."

Researchers made New Jersey a test case to see how the beetle moves north and to model its future path with climate predictions. The northernmost sightings were highly correlated with latitudes at which winter bark temperatures didn't plunge below 14 degrees Fahrenheit (the beetles feed on the bark). 

Southern pine beetles have eaten trees in Long Island and Connecticut in recent years but scientists didn't know if they were just summer visitors or if they were capable of longer infestations. With climate mapping, Horton said, researchers determined the insect could survive the winter as far north as Nova Scotia and then deeper into Canada by 2020. 

They also predict that by 2050, 78 percent of the 48,000 square miles now occupied by pitch pine forests from southern Maine to eastern Ohio will have climates newly suitable to the beetles. However, there are several uncertainties such as changes in the jet stream and snow cover, which were not modeled in the study.

The study points to “huge vulnerability across a vast ecosystem,” said lead author Corey Lesk, a graduate student at Columbia University’s Department of Earth and Environmental Sciences. “We could see loss of biodiversity and iconic regional forests. There would be damage to tourism and forestry industries in already struggling rural areas.”  

Horton said forest managers will need to prepare for the insects' arrival by thinning trees and quickly removing any that become infected.

The study said pine beetle infestations in the southeastern United States cost an estimated $100 million a year in timber losses from 1990 through 2004 alone, according to the U.S. Forest Service.