Due to infestation by the Emerald Ash Borer, approximately 17 ash trees were removed from campus grounds last week, primarily in the area around the parking lot at Empire and Park streets. Safety was a factor, with concerns about limbs falling as the trees succumbed to the infestation.

The Emerald Ash Borer is an invasive species that has been working its way south from Canada for several years. “It’s been called a natural disaster,” Assistant Manager of Grounds Services Ken Detloff said. “It takes out every single ash tree.”

In the years that the University grounds crew braced for the threat, they identified seven prominent ash trees for preventative treatment. Detloff described the treatment as “effective but costly,” and noted the environmental impact of using insecticides is a consideration in treating only selected trees.

Before the recent removal, there were 29 total ash trees on campus. Of the few remaining that aren’t being treated, most are located on city property — between sidewalks and street curbs — and will eventually fall under the city’s removal plans, Detloff said.

“We have a small percentage of ash trees compared with the rest of the community, so we’re fortunate,” he said. “Since all those elm trees came down years ago, we’ve really focused on diversity.”

In the 1950s, Dutch Elm disease killed more than 100 elms on campus. Today Illinois Wesleyan is home to more than 1,200 trees comprising nearly 150 different species, as noted on the campus tree map.