Skip to content
EAB in Colorado, threatening ash trees

Emerald Ash Borer Detected in Superior, Colo.

SUPERIOR, Colo. – State officials have confirmed the presence of emerald ash borer (EAB), an invasive, highly destructive tree pest, in the Town of Superior in southeast Boulder County. This new detection is still just within a quarantine area established to try and prevent the human-assisted spread of EAB. However, it represents the fifth community with confirmation of EAB in Colorado outside the City of Boulder, where the pest was first detected in 2013.

An estimated 15 percent or more of all urban and community trees in Colorado are ash species susceptible to being killed by EAB – and a majority of these trees are on private land. There are 1.45 million ash trees in Metro Denver, and in the City and County of Denver specifically, one in six trees trees is an ash.

EAB attacks and kills both stressed and healthy ash trees and is so aggressive that trees typically die within two to four years after becoming infested. Additionally, it may be years before an ash tree shows signs of infestation, and by then it may be too late to save. That’s why the Denver City Forester is recommending the preemptive treatment of ash trees in the metro area.

The pest was confirmed in Boulder this week, shortly after Boulder County foresters identified a dead adult EAB on a trap the county had set – along with a dozen others in targeted areas – to detect for early infestation of the pest. This particular trap was located on public property along the Mayhoffer Singletree Trail, near the intersection of West Thomas and Third Avenue in Superior.

Read more

Emerald Ash borer discovered in Lyons, Colorado

LYONS, Colo. — State officials have confirmed the presence of emerald ash borer (EAB) – an invasive, highly destructive tree pest – in the Town of Lyons in northern Boulder County. This new detection is still just within a quarantine area established to try and prevent the human-assisted spread of EAB. However, it represents the fourth community with confirmation of EAB in Colorado outside the City of Boulder, where the pest was first detected in 2013.

An estimated 15 percent or more of all urban and community trees in Colorado are ash species susceptible to being killed by EAB – and a majority of these trees are on private land. EAB attacks and kills both stressed and healthy ash trees and is so aggressive that trees typically die within two to four years after becoming infested.

An arborist recently identified an ash tree on private land in the vicinity of 4th Avenue and Broadway Street in Lyons as potentially infested with EAB. The property manager notified members of the interagency Colorado EAB Response Team, which is working to manage the spread and impacts of the pest in Colorado. An adult beetle specimen found in the tree was provided to the Colorado Department of Agriculture (CDA) and then confirmed by Colorado State University experts as being EAB. The infested tree and surrounding trees also are being examined by experts from the CDA and Colorado State University Extension.

Read more

Don’t judge a tree by its cover: Winter tree & EAB treatment guide

DENVER — Although winter is the time when trees go dormant, it is a good time to start planning for tree care. It might be hard to tell in the winter, but not all ash trees are healthy and thriving. They may look okay on the outside, but the inside might be another story, and no matter the time of year a tree professional can help assess your tree.

For example, a large ash tree in Louisville was recently removed causing a bit of stir in the neighborhood. The tree provided valuable shade to neighboring houses close to the downtown area. But, despite the healthy exterior, what couldn’t be seen on the outside was that the center of the tree was hollow. A hollow tree can be a major safety issue.

“A cavity in a living tree can contribute to a tree being unsafe,” said Sara Davis, Urban Forestry Manager, Office of the City Forester, City and County of Denver. “When a tree develops problems, it is frequently difficult to decide when to replace or remove it. The one option you shouldn’t consider, however, is treating or replacing your ash tree yourself if you’re not a licensed tree professional.”

Read more

Emerald ash borer discovered in Lafayette, Colorado

LAFAYETTE, Colo. — Emerald ash borer (EAB) has been discovered in Lafayette, the Colorado State Forest Service (CSFS) confirmed on Wednesday. Lafayette is now the third city in Colorado facing an EAB infestation.

Not entirely unlike the mountain pine beetle, which decimated pine trees across hundreds of thousands of acres in Colorado’s high country beginning in 2008, EAB has decimated ash tree populations in more than 25 states and parts of Canada, causing billions of dollars in damage over the last 15 years.

CSFS community forestry program manager Keith Wood also confirmed Wednesday the newly found infestation in Lafayette remains within Colorado’s EAB quarantine zone. That zone includes Boulder, where EAB was discovered in 2013, and Longmont, where EAB was discovered in 2016. Lafayette is less than 13 miles from each city.

“Having a new detection in this area was not unexpected,” Wood said. “But it certainly highlights the need for Front Range communities to be planning now, before EAB arrives.”

Read more