Boulder's Tree Protection Ordinances - Trees on Private Property
In The City of Boulder Land Use Code, there are specific provisions protecting trees on private property from construction damage. The "Tree Protection" provision of the Land Use Code 9-9-12 (18) states that all trees six inches or more in caliper and located in a development, in a required setback, or on a property line must be protected from construction impact. See Boulder Land use Code 9-9-12 (18)
In addition, the "Tree Protection" provision referenced above states that trees shall be protected from construction impacts within the "drip line" (ie the span of the tree’s branches or canopy) in a manner consistent with the standards set forth in the City of Boulder Design and Construction Standards' relating to tree protection for construction sites (the "D&C Standards")
The D&C Standards contain exhaustive procedures for tree protection under § 3.05. These protections include maintenance and care of existing trees, soil compaction prevention on the site, significant root protection, tree fencing, and limits on grade changes.
See Boulder’s Design and Construction Standards
Boulder's Tree Protection Ordinances - Trees on City Property
The Boulder Revised Code 6-6 also has extensive protection provisions for trees on city-owned property. Under this ordinance the city may also come onto private property to “prune, spray or remove any diseased or infested tree on private property….” See the Boulder Revised Code
With all of these provisions, why was the Champion Horsechestnut not protected?
With all of these detailed provisions for tree protection in place, you might ask , Why was the State Champion Horsechestnut Tree not protected? That is a very good question. You might be surprised by the answer.
Boulder's Tree Protection Ordinances, as they are now written and interpreted apply only to:
- trees within the confines of a property under construction
- trees on public property
“On the property line” has been interpreted by the city to mean trees on the construction side of the property line and does not include trees on the adjacent property’s side of the property line.
Since the trunk of the horsechestnut tree was on the adjacent property’s side of the property line, the tree was not considered to be on the property line as interpreted by the city and therefore did not fall under Boulder’s current tree protection ordinance.
What is the city doing about this?
Given the devastation to the Champion Horsechestnut, tree, the city acknowledges that the scope of itss tree protection ordinances must be reviewed and expanded. Trees a certain distance from the property line of a construction site must also be protected from damage.. That review is now in process. (Note: clarification of the term “tree” is also in order. A tree is clearly more than just its trunk – it is the trunk, the roots, the branches, and the leaves. If the roots are part of the tree and the roots of the Horsechestnut were on the developer’s side of the property line, why was that part of the tree not protected? This remains to be answered)
What you can do now to protect your tree/s.
With Boulder’s tree protection ordinances now under review, what should you do if you feel your trees are in danger from construction on an adjacent site?
Call the City of Boulder Office of Planning and Development services 303-441-1889 and ask to speak with a Project Specialist. Describe the location of the tree/s that concern you. Be sure to follow up until you get an answer that satisfies you. If in fact those tree/s need to be protected, ask the city to get you a detailed plan, in writing, describing the steps that will be taken to protect that tree/s. You can also reach the Office of Planning and Development at
What if your tree/s have been damaged by construction on an adjacent site?
If your tree/s have already been damaged by construction on an adjacent sit call Robert Ray, City of Boulder Land Use Manager, Office of Planning and development Services. 303-441-4277 email:
Stay informed
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