1 Billion Black Ash Trees in Peril: Scientists Invade Duluth to Share Emerald Ash Borer Research

Scientists have been studying emerald ash borers since the Chinese insects started killing ash trees near Detroit 15 years ago.

They’ve been following the imported insects’ march east, then north and now west and watching the bugs kill nearly every ash tree in their path.

But those were mostly green ash, with some white and blue ash, too — the kind of trees that once lined urban avenues, wooded parks and farm woodlots across much of the country.