From the hemlock woolly adelgid to the emerald ash borer to the mountain pine beetle, invasive insects are killing large swaths of our nation's forests.
According to a new report, extreme weather events linked to climate change - like droughts and flooding - are making the problem even worse.
Forester Jason Denham is fighting an invasion that's killing trees across the northeast. The hemlock woolly adelgid is hard to see with the naked eye, but the tiny invasive species of insect is having a gigantic impact from Georgia to Maine and is threatening delicate eco-systems that rely on the hemlock tree. According to Denham, the hemlock woolly adelgid is present in about half of New York State. He says trees stressed by climate change are more likely to succumb and die from an infestation, adding "eventually they rot and that carbon dioxide is released back into the atmosphere."
A recent study from Purdue University shows invasive pests kill so many trees each year that it's equal to 5 million car emissions. The study also estimates that if unchecked, invasive insects could eventually kill off 41% of trees in the continental U.S.
Denham and teams at the New York State Department of Environmental Conservation are doing what they can to save the trees, spraying insecticides and releasing natural enemies of the insects. It's a high stakes battle. Denham says, "There will still be life here when these hemlock trees are gone, but it won't be the same place."
More than 430 non-native insects and diseases have invaded American forests, according to the U.S. Forest Service.