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Emerald ash borer was confirmed in Denver in June 2025, and about 1 in 6 trees in the city is an ash. Tree Services Denver Colorado inspects ash trees, tells you whether treatment or removal makes sense, and removes infested and declining ash trees safely. Call (720) 383-6040 for a free quote.
Emerald ash borer (EAB) is an invasive beetle whose larvae tunnel under the bark of ash trees and cut off the flow of water and nutrients. It was first found in Colorado in Boulder in 2013 and was confirmed in Denver’s Congress Park neighborhood in June 2025. Denver has about 330,000 ash trees, and the city’s Be A Smart Ash program expects ash that are not treated or replaced to be lost.
That leaves ash owners with three options: protect a healthy tree with insecticide treatment, remove a tree that is declining or badly placed, or replace it with another species. Our certified arborists inspect the tree and tell you which option fits. We handle the tree removal, stump grinding and cleanup.
We confirm the tree is an ash, then check it for emerald ash borer signs: dieback at the top of the crown, D-shaped exit holes about 1/8 inch wide, winding tunnels under the bark, new sprouts on the trunk and heavy woodpecker activity.
We explain what we found and which option fits the tree’s health, size and location. Healthy, well-placed ash are candidates for insecticide treatment, which in Colorado must be applied by a state-licensed pesticide applicator. Declining ash and ash under power lines are usually better removed.
Ash killed by emerald ash borer turns brittle, so the crew takes the tree down in sections with professional equipment and keeps it clear of roofs, fences and utility lines.
We clear the wood and debris and provide stump grinding, so the spot is ready for a replacement tree of a different species.
Dead and dying ash are among the riskier trees to take down. This is what you get with our Denver crew:
Insecticide treatment protects healthy ash trees, and Denver’s Be A Smart Ash program puts properly applied treatments at about 90% effective. Trees that have already lost much of their canopy are poor candidates.
Ash wood dries out and turns brittle after the tree dies, so limbs can drop without warning. Removing a declining ash early is safer for everyone working on or living near it.
Removing infested trees, and not moving ash firewood around, limits how far the beetle travels to neighboring trees.
Replacing an ash with a different species rebuilds your shade and helps diversify Denver’s tree canopy.
We inspect and remove ash trees throughout the City and County of Denver, including Cherry Creek and the neighborhoods below. About 1 in 6 trees in the city is an ash. Here is what ash owners in each area should know.
Ash were planted widely as street and yard trees. On tight lots a declining ash stands close to the house, so early removal is safer.
Emerald ash borer was first confirmed in Denver here in June 2025. Every ash in the neighborhood should be inspected.
Large ash over older homes are worth assessing early. Healthy ones may be candidates for treatment, declining ones for removal. See treat or remove your ash tree.
An ash between the sidewalk and the street is in the right-of-way and needs a free city permit to remove. See tree removal permits in Denver.
Check for ash before a rebuild. A declining ash in a setback still needs City Forester approval to remove during construction.
Any ash here are young and small. The city’s Be A Smart Ash program recommends replacing small ash with another species. See what to plant instead of ash.
Yes. Emerald ash borer was identified in Denver’s Congress Park neighborhood on June 17, 2025, and confirmed by Colorado State University and the Office of the City Forester. It had already been found in Boulder in 2013, Arvada in 2021, Littleton in 2023 and Lakewood in 2024. The full picture is in our guide to emerald ash borer in Denver.
Ash trees have compound leaves made up of 5 to 9 leaflets, branches and buds that grow directly opposite each other, and diamond-patterned bark on mature trunks. About 1 in 6 trees in Denver is an ash, so there is a fair chance you have one in your yard or along your street. See the checklist in how to identify an ash tree.
Treatment suits ash trees that are healthy, well placed and worth keeping for years. Removal is the better choice for ash that are already declining, small, poorly located or growing under power lines. An arborist inspection tells you which group your tree is in. Work through it with should you treat or remove your ash tree?
Anyone paid to apply pesticide to protect ash trees must be licensed by the Colorado Department of Agriculture as a commercial pesticide applicator. You can check a company on the department’s applicator search. We can inspect your ash and tell you whether it is a candidate for treatment.
Most trees on private property in Denver can be removed without a permit. An ash in the public right-of-way, usually the strip between the sidewalk and the street, needs a free permit from the Office of the City Forester. During demolition or construction, trees in the front and side setbacks are also protected and need a permit to remove.
The price depends on the tree’s height and trunk diameter, how far it has declined, how close it stands to buildings and utility lines, and whether stump grinding is included. Dead ash is brittle and can need extra rigging. Each tree is quoted individually, and quotes are free.
The city looks after ash trees on city property such as parks and has treated selected right-of-way ash through its Be A Smart Ash program. Ash trees on private property are the owner’s responsibility. Details are in Denver’s free tree and ash replacement programs.
Choose a species other than ash, so that one pest cannot take out the replacement too. The Office of the City Forester publishes a list of approved trees, and Denver has offered free replacement trees for some right-of-way locations. See what to plant instead of ash in Denver.
