Ash Trees and Emerald Ash Borer

The City of Boulder has been actively managing EAB since 2013. At that time there were over 6,000 public ash trees in Boulder. With the support of City Council, Boulder Forestry's EAB program involves preserving approximately 1,300 public ash trees, removing infested ash trees, increasing tree planting efforts, releasing biocontrols and educating the public.

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Enter your address on our public ash tree map to find out if you have a public Ash tree near you and if it has been treated. This map shows only publicly owned ash trees.

Public Ash Tree Map

Yes. However, you must fill out the form below so that Boulder Forestry knows it is being treated. You must hire a contractor who is a “licensed certified arborist” and use an injectable non-neonicotinoid pesticide such as emamectin benzoate or azadirachtin. Use of neonicotinoid pesticides, such as imidacloprid and dinotefuran, are prohibited on public property in the City of Boulder. Common products sold for EAB treatment that contain Imidacloprid include “Bayer Advanced”, “Merit”, and “Safari”. These products must not be used to protect public ash trees.

We recommend you hire a licensed certified arborist to first evaluate your ash trees. If you decide to move forward with treatment, we recommend an injectable non-neonicotinoid pesticide treatment containing either emamectin benzoate or azadirachtin. We encourage homeowners to limit the use of neonicotinoid pesticides on private property. All EAB treatments must be reapplied every 1 to 3 years depending upon the product. Holistic, natural or compost tea treatments are not effective against EAB.

Licensed Arborists and Tree Contractors

Tree Planting

Boulder Forestry provides and plants tree in approved public Right of Way locations each spring at no cost to residents. The City works with the resident to select an appropriate tree species and location at each proposed site. In return for this service, residents must agree to adequately water and maintain mulch under the tree.

Street Tree Planting Program

Your deed should show your property line location and where the public right of way begins. You may also visit the  Planning Department office to speak to a planner in the main lobby. A planner should be able to tell you specifically what the right-of-way distance is at your property. To start, you may also visit the Boulder County Assessor's Office property search.

Memorial and Living Legacy trees are planted in city parks in the spring (March 15 – June 1) or in the fall (Sept. 1 - Nov. 1) and the cost is $350/tree. The tree species depends upon location and the city park chosen for planting.

Living Legacy Tree Donations

The City provides trees of various sizes and species through tree giveaways (seedlings) and subsidized tree sales in partnership with Cool Boulder - PLAY Foundation (#5 to #15 containerized trees depending on the event) to assist homeowners in increasing Boulder’s urban canopy. Keep on the News for upcoming events.

In theses instances, the tree(s) must be purchased and planted by the applicant/property owner as per the guidelines set by the City Planning and Development Services Department. These trees are not supplied by the city’s Street Tree Planting Program.

Tree Care

Yes. Property owners or residents agree to water and maintain mulch on new street trees adjacent to their property as part of the City’s Street Tree Planting Program. Water your new tree at least once per week from May 15 to Sept.15, using about 25 gallons per watering. Water at a slow rate from the end of a hose. You can time how fast it takes to fill a five-gallon bucket and multiply by five to determine how long you should water. Water the same amount once per month from October through April.

Tree planting, care and watering information

Have you been watering your tree? If not - see above and begin! If you have been watering, your tree could be in "transplant shock." Trees may lose a lot of roots during the transplant process, but most trees fully recover in a relatively short period of time. We are happy to come out and look.

Submit a Request

We recommend you always get bids from at least three companies and ask for references.

Licensed Arborists and Tree Contractors

Tree Removal

The tree that is marked with a painted 'X' facing the street.

If the tree is not an untreated public ash tree, it has most likely been marked for removal because it is dead, dying or structurally unsound. To learn more about the tree, please call the phone number on the business card/doorhanger you received or call the Boulder Forestry office at 303-441-4406.

Submit a Request

Yes. Each spring, Boulder Forestry plants replacement trees in the public street rights-of-way. Please request a replacement tree online if your tree is scheduled for removal or has already been removed. Boulder Forestry works with the resident to select an appropriate tree species and location at each proposed site. In return for this service, residents must agree to adequately water and maintain mulch under the tree.

Street Tree Planting Program

If it is a private tree, you do not need permission to remove it unless the property is under a development agreement or currently in the city planning permitting process. All companies performing work to either public or private trees must be licensed through the city of Boulder. Boulder Forestry wants to remind residents to only hire only licensed tree care companies to perform work on their trees.

Yes. All public trees are protected by ordinance and cannot be removed without permission from Boulder Forestry. If a public tree is removed without permission, the property owner could be assessed the value of the tree as mitigation. Please submit a request for permission.

Submit a Request

If the tree will impact public property (street, sidewalk, alley, park) if it failed, the answer is yes. Please submit a request. If the tree will only impact private property if it failed, it is a private matter between the two property owners. We do recommend you talk directly to your neighbor about the tree. If this is unsuccessful, contact a private tree care company to have the tree inspected, then send the arborist report to the property owner so they are aware of the situation.

Many trees in alleys are on private property. Trees in the alley right-of-way are cared for by Public Works Transportation. Please create a request or call 303-413-7162.

Create a request

Generally, the ditch company has only an easement to run water in the ditch and adjoining property (and trees) are private property and the responsibility of the adjacent property owner.

Boulder County Property Search


To be as efficient as possible, we prefer to prune public street trees during our neighborhood rotational pruning schedule. We will prune trees outside of the rotation if the trees pose a safety concern (generally, deadwood larger than 6” diameter, broken branches, or hanging limbs). Low hanging limbs will be evaluated and pruned as needed. All our work is prioritized however so safety concerns are given priority over clearance issues.

Submit a Request

Yes, however you must hire a contractor who is a “licensed certified arborist.” The city will not reimburse you for the cost of this work. Any work proposed on a public tree must be approved first by Boulder Forestry. In the request, please clearly indicate the nature of work and contractor you propose to hire.

Licensed Arborists and Tree Contractors

Broken, hanging or fallen limbs and branches

Broken, hanging branches can be very dangerous so we prefer you call these in to the Boulder Forestry office at 303-441-4406 and not log a request through the Inquire Boulder system. Please include the exact address of the tree, size of the branch (diameter of the branch), location in the tree (i.e. 30’ above the sidewalk OR broken and hanging down to the ground) and target should the branch fall (sidewalk, street, house, etc). This information helps us prioritize the calls and respond as quickly as possible.

We recommend you consult a licensed certified arborist. If the tree is on your neighbor’s property, please talk to your neighbor before performing any work to their tree yourself or hiring someone to perform the work.

Licensed Arborists and Tree Contractors

Limbs on the ground are a lower priority than broken limbs still up in the trees. Once we have responded to all the reported broken limbs still up in the trees we will focus on large limbs on the ground.

Submit a Request

Please submit a request with the correct address closest to the tree. Often, we’ll get a report of the same tree from multiple residents. This will help us focus our efforts.

The city will pick up limbs from public property trees that are 10 inches in diameter and larger.

Submit a Request

Every storm is different, and the City response depends upon the storm severity. There are also far fewer public than private trees in Boulder. Therefore, for most storms, the city relies upon the adjacent property owner to dispose of the branches from both public and private trees.

If the city determines the storm wasn't severe enough to merit a citywide branch collection, then limbs on private property are the responsibility of our community members. If you have tree limbs that are less than 10 inches in diameter, please pull them out of or to the side of the Right of Way.

Bundled branches no more than 6 feet long and 3 inches in diameter can be placed into or next to curbside compost bins for pickup by your trash/compost hauling service. You can also take broken branches from your property to Western Disposal at 5880 Butte Mill Rd. Check out our Forestry FAQs for more information about fallen limbs.

In rare situations after a severe storm, the city may decide to conduct a citywide branch collection. If this decision is made, a news release will be sent out and information posted on the City website. Citywide clean-ups are quite expensive, and most debris collected from past storms has been from trees on private property.

General Questions

Mulch is available at the Operations/Forestry lot. Access is off of Pearl Parkway. Look for a sign posted at 5400 Pearl Parkway, near Sunbelt rentals return.

Firewood is available through the OSMP Firewood Program.

Slacklining is only allowed on designated trees.

Interactive map + more information

What is the Boulder Apple Tree Project

The Boulder Apple Tree Project seeks to document more than 1,000 of the county’s oldest apple trees to learn more about the apple industry that previously thrived here while also building community connections and identifying and preserving heirloom varieties.
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