The City of Fort Collins says a problem with an invasive species continues to grow. The city’s forestry division says emerald ash borer, a species of beetle, is destroying trees within city limits.
Foresters first detected emerald ash borer in Fort Collins in May of 2020, but this past summer they were able to easily spot dead and dying trees impacted by the bug as the problem has spread.
"Early in an infestation it takes a few years to kill a tree, but later on when the populations are high, the trees can die in one or two years," said Ralph Zentz, an assistant forester with the City of Fort Collins.
The invasive species first appeared in the U.S. in 2003. Fort Collins has made efforts since then to treat trees, in particular ash trees. That's where the insect lays its eggs. Once that happens, it’s too late for treatment and the tree needs to be removed as the beetle’s larva feeds under the tree’s bark. The end result is brittle trees that become a fall hazard.
The city has been treating about 700 trees on city land a year. Ash trees make up about 14% of those trees and 33% of the city’s entire tree canopy.
Zentz says the city needs homeowners’ help to protect ash trees.
"If you want to save your tree, you need to protect it, and the only real protection is chemical protection,” said Zentz.
Fort Collins is also trying to kill the invasive pest with parasitic wasps. In the meantime, the city shared a list of local arborists who are available to help homeowners protect their trees.