Denver could lose one-sixth of all trees
“Be A Smart Ash” program educates private property owners to the treat of the emerald ash borer
More than one year into an ambitious citywide campaign to prevent an outbreak of the invasive emerald ash borer, Denver officials still have not detected any traces of the tree-killing insect in the metro area — so far.
“If you talk to any arborist or tree expert in the country, they say that eventually the ash borer will move into the Denver metro area,” warns Rob Davis, city forester for Denver Parks & Recreation. “The time to start treating trees is now.”
Early success preempting infestation has heartened city leaders, whose proactive efforts have borrowed from — and helped define — best practices against the malignant pest. Experts consider the predatorless emerald
ash borer, first detected in Boulder in 2013 and spotted again in Longmont last June, to be “the most destructive tree insect ever to be introduced into North America.” Preventative measures include treatment for at-risk ash trees, thousands of new tree plantings in public parks and on city streets, and the launch of an information campaign — Be A Smart Ash — to educate private property owners of the looming danger.
Officials stress that Denver has a long way to go before the all-clear and encourage residents to remain alert.
“We need to start making investments in this now, because it will dramatically reduce our costs later,” says Jolon Clark, who represents Denver’s 7th district on the City Council. “A dollar today will save us dozens down the road. It’s hard saying that we need $3 million to deal with a problem we can’t see yet. But that’s what we’re doing because of the passionate people of Denver who are looking ahead to problems in two, five and 10 years.”
According to the Colorado Department of Agriculture, the Denver metro area has an estimated 1.45 million ash trees, or one in every six trees in the city. The metallic green insect has decimated ash trees in Canada and the Midwest, inflicting billions of dollars in damages in just 15 years. A report from the Colorado State Forest Service estimates that the economic damage to metro Denver alone could total $82 million.
In June 2015, Clark and Davis visited Midwestern cities to assess ash tree devastation and learn effective strategies from municipal leaders in Chicago, Milwaukee and Madison.
“Everyone said, ‘we wish we could have gotten ahead.’ Because by the time you find it, you’re four to five years into the infestation, and by then it’s too late,” Clark said. “Some cities had no treatment, and every single ash tree died.”
Denver hopes to avoid that fate. Success will ultimately depend on private property owners, who control more than 90 percent of all ash trees in metro Denver.
Be A Smart Ash relies on big data and clever marketing to raise public awareness. Residents can use an interactive map to identify trees on their property and can request a free replacement tree through a publicprivate partnership. The initiatives, enabled by a complete tree inventory completed in 2016, have led to 4,500 free tree plantings on private property, according to Davis. The city plans to replace all ash trees on city streets by 2026.
In February the city’s Parks & Recreation department released a staffproduced educational music video that lays out practical steps for keeping ash trees healthy. The city has also tagged thousands of trees with bands promoting the campaign.
To professional arborists like Davis, the stakes for containment are high and matter beyond mere aesthetics. Trees enhance air quality, raise property values and provide necessary cooling and shading for a metro region undergoing rapid development.
Plus, sick trees fall, causing massive damage to pedestrians, roadways, property and infrastructure.
“If all these trees were to die right away, we’d have a disaster on our hands,” says David Edinger, the chief performance officer for the city and county of Denver. “We wouldn’t have the resources to move trees off the streets, sidewalks and properties quickly enough. There’s a practical, operational need to be proactive.”
With the benefit of location, Denver has a trove of best practices from across the country to study and apply. Still, how the city succeeds or fails will help chart the course for regional municipalities yet to confront the tree-decimating predator.
“Other cities are all going to look at what our city forestry team and parks department has done,” Clark said. “This is now the model for dealing with a bad situation.”
A emerald ash borer adult on an ash tree leaf.
A screen shot from a video titled, “Get Ready for Emerald Ash Borers in Colorado” on the Denver Botanic Gardens YouTube page.