The invasive insect pest, the Emerald Ash Borer, was first discovered along the Front Range in Boulder County in 2013. The beetle first arrived in from Asia the 1990s, hitching a ride on imported wooden pallets. The insects have killed many thousands of ash trees in the Midwest U.S. and have made their way across the country.
Although no instances of Emerald Ash Borer infestation have been found in Golden yet, Golden’s Forestry Department is preparing for the insect onslaught on the city’s 15,000 ash trees, the city said in a press release.
“It’s generally accepted that EAB will eventually make its way outside of Boulder County into all communities surrounding Boulder, Denver, and Golden,” a statement said.
The beetles kill the trees when adult beetles lay eggs on the outer bark and larvae bore into the bark to feed on the inner parts of the tree, disrupting the transportation of water and nutrients and causing the tree to die.
The history of the insect’s movement in 22 other states has shown that without treatment, “entire populations of ash trees are almost inevitably killed,” the city said.
Property owners with ash trees they do not want to lose should be aware that “now is not too early” to consider applying a preventative treatment on Green Ash (Fraxinus pennsylvanica) or White Ash (Fraxinus americana) trees on your property. The most effective treatment consists of an injection into the bark, repeated every 2-3 years, the city said. To find out about treatments, consult a certified arborist.
As for the city’s ash trees, City of Golden’s forestry staff have chosen around 300 ash trees for treatment. These trees are in good planting locations, considered to be highly valuable to the community, in good condition, and good candidates for future treatments.
Other ash trees in public parks and streetscapes that are in poor health will be “marked for removal and replacement,” the city said.
Ash trees were widely planted on the Front Range in Colorado in the past because they thrived here, but the ash “is no longer recommended as a planting choice anywhere in Colorado,” the city said.
Replacement trees planted by the city’s forestry staff will be of diverse types to avoid being wiped out by any species-specific pests (such as EAB or Dutch Elm Disease) in the future, the city said.
For now, the forestry department will conduct branch sampling and an on-going search for evidence of EAB in Golden into the foreseeable future.
If you are uncertain whether a tree you value on your property is an ash or not, or if you have any other questions or concerns, contact the City’s Forestry office at 303-384-8141 or [email protected]