Tree Resources for Property Owners

Helpful Resources

The recent confirmation of Emerald Ash Borer (EAB) within the City of Boulder introduces a new tree pest to the metro-Denver urban forest that could impact 100’s of thousands of property owners across the Front Range of Colorado. Denver alone has an estimated 330,000 ash trees at risk, and losing these trees will have adverse economic, environmental and social impacts on our community. Over the next decade EAB has the potential to destroy more of Denver’s urban forest than any other disease or pestilence in history.

State officials have established quarantine boundaries for Boulder County, and it is important to stress that this is currently the only known infestation in the state. The Colorado Department of Agriculture will be working to perform inspection and sampling surveys across the City of Boulder in an effort to determine the extent of the infestation.

Since the announcement of EAB being found in Boulder, Denver’s Forestry staff members have completed several hundred miles of inspections and at this point no signs of EAB have been found within Denver.

With now over a decade of EAB experience in North America, it has become very clear that ash trees can be well protected through proper preventative pesticide treatments. The Colorado Department of Agriculture does not recommend property owners start EAB preventative treatments until an infestation is found within 5 miles of a property.

At this point in time Forestry is working to identify significant ash trees within parks and public rights-of-way, and developing an official EAB response plan for Denver. If you have specific questions about park ash trees, or the right-of-way ash trees adjacent to your private property send a message to

Below are some helpful links for property owners seeking further information:

Colorado Department of Agriculture EAB Webpage   
How to Identify Ash Trees   
How to Identify EAB   
EAB Pesticide Treatment Research   
Frequently Asked Questions

One of the things that makes Denver such a beautiful, livable city is our diverse array of trees.  Selecting the right tree for your site assures a healthy tree that will provide many years of benefits and enjoyment.  Denver Forestry has prepared this helpful guide to show you which tree species are recommended and which tree species are not permitted to be planted in the public right-of-way.

Not all tree species are approved for planting along Denver streets within the public right of way. 
Click here for Denver’s approved street tree list.

For more information contact the City Forestry office at 720-913-0651.

Vegetation Ordinance (Chapter 57) requires that anyone performing tree care services including pruning and removing be licensed as a "Tree Service Company." When requesting services, ask to see evidence of license from prospective companies. Companies on the provided list have passed the minimum test requirements of the Office of the City Forester. Testing does not guarantee quality of work, please choose a contractor wisely. The Office of the City Forester does not Endorse any one company on the list. We do recommend that before you enter into any contractual agreement you receive at least three written, detailed bids and check references. If you feel a licensed tree company on this list has provided low quality work or has behaved in an unethical manner please contact our office at 720-913-0651 or  

In some cases, these licensed tree companies have additional certifications through the International Society of Arboriculture (ISA) or Tree Care Industry Association (TCIA). Please see the link provided HERE to see the ISA credentialed companies. 

If you would like to check if a licensed tree company is also a licensed pesticide applicator please visit the Colorado Department of Agriculture for contact information. 

Current Licensed Tree Contractors
When the time comes to prune or remove a tree, there are some important questions that need to be answered.  Most importantly there needs to be an understanding of whether the tree in need of maintenance is located on private property or within the public right-of-way.  While property owners in Denver are responsible for maintaining the city trees within the right-of-way adjacent to their property, there are some very important regulations that protect how those trees are managed.
Chapter 57 of Denver’s municipal code makes it is illegal to remove a right-of-way tree without first obtaining an approved permit from the City Forester.  Denver’s street trees provide environmental, social and economic benefits that are of value to all residents, and for these reasons removal permit requests for healthy trees of value will often be denied.  City trees that are removed without a permit are often worth thousands of dollars, and the city code requires that the responsible party compensate the City of Denver for the lost monetary value of the tree to the satisfaction of the City Forester.
The majority of trees on private property may be removed at the discretion of the property owner and their removal does not require a permit.  However, when a property is in the process of demolition or construction, the zoning code grants the City Forester regulation over the trees within the front and side setbacks of the property.  During demolition and construction, all trees located in the setbacks of a property must be protected and preserved throughout the project, and trees may not be removed without a permit from the City Forester.
Tree work is a dangerous activity, and major work often requires highly skilled individuals to complete the work safely.  The professional arborist not only needs to been trained in safe tree work practices, but they also need to be well educated to understand the biology of trees.  As trees are valuable and complex living organisms, the professional arborist can protect tree health and ensure the work is done safely.  For the protection of person, property and tree health, Denver’s city code establishes that it is unlawful for any person to engage in the business of cutting, trimming, pruning, or removing trees with a license.  The City Forester is obligated to establish and monitor licensed tree contractors for the City and County of Denver.
There are currently no requirements for permits to prune private property or public right-of-way trees.  However it is very important to understand that city code does require that all pruning of right-of-way trees be done to industry standards.  A private property owner is allowed to prune the city trees within the right-of-way adjacent to their property, but the work must be done not damage the trees.  If a right-of-way tree is improperly pruned (topping for example) the City Forester may deem the tree to be irreparable damaged and reimbursement for the value of the tree may be required.

If you are a property owner who has received a notice of violation from the Office of the City Forester please review the following information closely.  

City code requires property owners to maintain the trees on their private property and also maintain the trees located within the public right-of-way adjacent to their property.  The City Forester is directed by this code to order the removal or pruning of trees that are determined to be dangerous, diseased, or an obstruction of the right-of-way.  Thousands of notices of violation are sent to property owners every year related to Chapter 57 of the municipal code and it is the property owner’s responsibility to comply with these notices within the established time frame.  

If property owners do not take action to correct the violation, or they do not contact the Arboreal Inspector who issued the notice to request an extension, administrative citation fines may be issued to the property owner.  

If a violation continues to go unresolved, the City Forester is directed by code to take action to have the violations corrected. The city Forester will authorize a low-bid on-call licensed tree service to remove or prune the tree(s) in violation, and the property owner is obligated to reimburse the Parks and Recreation Department for the costs of this remediation.  If the property owner does not work with the Department to pay back these expenses, city code requires the Department to place a lien on the property to secure the debt.  If the debt continues to go unpaid, the Department is directed to send accounts to a collection agency to pursue reimbursement. 

Please review the following important tips for successfully working to correct a notice of violation:

  • Stay in close contact with the Arboreal Inspector who issued your notice. Your Inspector has the ability to answer your questions, offer time extensions, and provide direction for hiring licensed contractors.
  • Property owners who do not take action to correct their violation, or make efforts to contact their Inspector for assistance, may be issued administrative citation fines.
  • Property owners have the right to appeal notices by sending the details of their appeal in writing to the Manager of Parks and Recreation. City code establishes that this appeal must be submitted within 15 days of the order.
  • Property owners have the right to appeal administrative citation fines by sending the details of their appeal in writing to the Manager of Parks and Recreation. City code establishes that this appeal must be submitted within 10 days of the date the citation was served.
  • Trees infected with a communicable disease or pestilence that threatens the good health of other trees (like Dutch elm disease) must be promptly removed. Infected wood must be disposed of as deemed appropriate by the City Forester to prevent further infections. Infected wood is almost never allowed to be stored as firewood, and typically must be promptly chipped, buried, debarked and/or burned.
  • Tree stumps are not allowed in the right-of-way, and must be ground out to 6 inches below existing grade.
By code, a permit is required from the Office of the City Forester prior to planting or removing trees from the public right of way.

These permits are free to the public, but must be approved by a representative of the City Forester.

If you are hiring a licensed contractor, they will be responsible for pulling all permits.

To request a permit please send a detailed email (including address, contact information, and species to be removed or planted) to [auto populate subject line to say Permit Request]

Contact Us

For specific questions about trees in Denver or a notice/citation you received contact:

Denver Forestry
(720) 913-0651

Arboreal Inspectors monitor Right of Way tree safety and health as well as the spread of disease and pests citywide.
Find your arboreal inspector (PDF)

Parkway supervisors respond to Park & Parkway trees.
Download the supervisor map (PDF)

For general information about trees such as what type of tree you have in your yard, information on common diseases or pests please contact the Denver County CSU Extension office:

Colorado Master Gardener
Help Line 

Denver Master Gardener
(720) 913-5278

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