Emerald Ash Borer in Denver Colorado; Restrictions for Dumpster Rental.

The emerald ash borer (EAB) continues to be a significant problem in and around Denver, Colorado. This invasive insect, first detected in Boulder in 2013, has spread to various areas including Littleton and Broomfield. It poses a substantial threat to the region's ash trees, which make up about 15% of Colorado's urban forests. In the Denver Metro area alone, there are an estimated 1.45 million ash trees at risk.

How the Emerald Ash Boar Kills

The emerald ash borer larvae burrow serpentine paths below the bark of the ash tree and subsequently cut off the water and nutrient flow essential for the tree’s survival. After development, the adult borer emerges in the spring and lays more eggs that again become larvae that burrow under the ash tree’s bark. The adults feed on the foliage of the tree and usually start at the top and work their way down. It may take 3 or more generations to kill an entire tree.

They Can't Fly, Don't Give Them Rides

While the emerald ash borer has no natural predators, it is not capable of flying long distances, so the quarantine and restricted movement of certain wood materials appears to be the best course of action.

Expanding Their Presence

Despite efforts to control its spread, the EAB has continued to expand its presence, with recent detections in new areas like the southern Denver Metro and even the Western Slope near Carbondale. Treatments and preventive measures, such as chemical injections to protect high-value trees, are in place but can be costly and require ongoing maintenance.

The infestation has led to the removal and treatment of many ash trees to prevent further spread. The exact number of acres deforested in 2023 due to EAB is not specified, but the impact on the urban forest is significant, leading to increased costs for tree removal and treatment, as well as a loss of canopy cover and related benefits.

Property Owners Can Fight

For residents and property owners in the affected areas, it's recommended to identify ash trees on their property and consider preventive treatments if they wish to preserve these trees. Preventative treatments applied by a professional can reduce the risk of Ash tree death by 90%.

The City of Denver is using preventative treatments on all city owned Ash trees.

Source: https://denver.extension.colostate.edu/programs/horticulture/emerald-ash-borer/

Apply for a Free Tree

Denver Parks & Recreation’s Be A Smart Ash is giving away free trees for property owners in Denver whose property meet certain conditions for tree growth. Hundreds of thousands of Denver's Ash trees are being cut down to fight the Emerald Ash Boar, help replace them by planting a new tree on your property.

If you are considering planting a tree in Denver, make sure it is on the list of approved Denver Street Trees. This helps keep invasive pests like the Emerald Ash Boar out of Denver.

If you have property that has an Ash Tree in poor health, you can have it replaced for free if you meet certain criteria. Check it out here: https://beasmartash.org/ashreplacement/

Quarantine and Restricted Areas

Ash tree materials may be moved within the quarantine area. Besides the general public, industries most immediately affected are tree nurseries, firewood companies and cleanup and trash companies. Ash tree nursery stock cannot leave the quarantine area, all firewood classified as hardwood must be treated before it can move outside the quarantine boundaries, and waste and yard materials that include any ash or hardwood must be transported to specific landfills.

In and around Denver, the Emerald Ash Borer (EAB) has led to the establishment of several quarantine zones to prevent the spread of this invasive pest. These zones primarily include:

• Boulder County: The initial detection site in 2013, this area has remained a focal point for quarantine efforts.
• Broomfield: Recently confirmed as having EAB infestations outside the original quarantine zones.
• Jefferson County: Includes areas like Arvada and Lakewood where EAB presence has been noted.
• Adams County: Part of the broader Denver Metro area, which has seen preventive measures and monitoring.
• South Metro Area: Cities such as Littleton, Englewood, Highlands Ranch, Greenwood Village, Lone Tree, and Centennial have all been part of the containment efforts.
• Larimer County: Includes areas like Fort Collins and Loveland, where EAB presence was confirmed more recently.
• Western Slope near Carbondale: A newer detection, indicating the pest's spread beyond the Front Range.

These quarantine areas are designed to control the movement of ash wood and prevent further spread of the EAB. Property owners in these zones are encouraged to treat their ash trees proactively and adhere to guidelines on firewood movement and disposal.

“Waste companies, particularly those in the roll-off and dumpster business, should closely inspect any load before leaving the designated area.”

What Can You Do About It?

If you have Ash Trees on your property you can treat them. If you have poor looking Ash Trees on your property, these attract the Emerald Ash Boar - so removing or replacing them with healthy trees help. You can plant a new Ash tree. If you live in EAB quarantine zones you can inspect wood or trash before transport and ensure you are not giving a forest killing bug a free ride.