Do you need a permit?
Yes — a permit is required
Cambridge has the strictest private-tree rule in Massachusetts and the bar is low: any tree 6 inches DBH or larger on your lot is a "Significant Tree," and the ordinance is blunt — "For any Significant Tree removal, a permit will be required from the City Arborist." Unless your tree fits one of the special circumstances, you also owe mitigation: replacement planting, or $850 per diameter inch into the Tree Replacement Fund.
Size threshold
"Significant Tree." Any tree six (6) inches DBH or larger which is on a Lot. "Exceptional Tree." Any Significant Tree thirty (30) inches DBH or larger which is on a Lot. "DBH (Diameter at Breast Height)." The diameter of a tree trunk measured in inches at a height of four and one-half (4.5) feet above the ground.
What's protected in Cambridge
- Significant Trees — any tree 6 inches DBH or larger on a lot. Permit required to remove.
- Exceptional Trees — Significant Trees 30 inches DBH or larger. Valued at 1.5 times their diameter for mitigation, and they often require extra documentation.
- Replacement Trees — stay identified as Replacement Trees for 10 years after planting, and a permit is required to remove one regardless of its size.
- Public street trees, protected separately under M.G.L. c.87. A healthy public tree proposed for removal requires an advertised public hearing.
How to apply in Cambridge
- 1
Measure the trunk diameter at 4.5 feet above the ground. At 6 inches or more you need a permit.
- 2
Check whether your tree meets a special circumstance that waives mitigation — 100% dead, dangerous, an emergency such as an uprooted tree, significant negative impact on an existing structure, or removal that benefits other Significant Trees on the property.
- 3
Hire a Certified Arborist. Most applications require one, and the city is explicit that "The City Arborist and other Urban Forestry staff cannot serve as Certified Arborists for private tree removals."
- 4
Take the required photos: one showing the entire tree including its crown, one showing the diameter or circumference measured at 4.5 feet, and photos of the dead or dangerous condition if you are claiming one.
- 5
Have the arborist complete Form A, plus the ISA Basic Tree Risk Assessment Form if the tree is dangerous.
- 6
If part of the trunk sits on a property line, include a letter of approval from the neighbouring owner.
- 7
Submit the application online through the city's OpenGov portal, then either plant Replacement Trees or pay the mitigation payment. Incomplete applications are not processed.
Fees, penalties, and the ordinance
- Fee
- The ordinance leaves the permit fee to the Commissioner of Public Works. The cost that actually bites is mitigation: "the current cost is $850 per inch diameter at 4.5 feet. Properties with Residential Exemption pay 10% or $85 per inch diameter at 4.5 feet." No mitigation payment applies to property owners receiving established forms of financial assistance.
- Penalties
- Failure to apply for and receive a permit, or to replace a Significant Tree or pay into the Tree Replacement Fund, "shall constitute a separate violation of this Chapter for which there shall be a fine of not more than $300.00. Each day such violation continues shall constitute a separate offense." Continuing work after a stop work order carries the same $300 per day exposure, and the city may also seek an injunction.
- Ordinance
- Cambridge Municipal Code Title 8, Chapter 8.66 — Tree Protection (the Tree Protection Ordinance). Enacted by Ord. No. 1405, 2-25-2019; substantially amended by Ord. No. 2021-7, 6-28-2021.
Worth knowing
- Mitigation can be satisfied by planting instead of paying, and planting can eliminate the payment entirely. Most owners plant 2-inch caliper Replacement Trees. Arborvitae and other privacy-hedge species do not count.
- The formula: subtract the Replacement Tree caliper from the Significant Tree diameter, divide by two, and multiply by the per-inch cost. Extra Replacement Trees beyond the number removed are credited against the balance.
- A permit is required to remove a Replacement Tree at any size for ten years after it is planted, and no mitigation reduction is available for that removal.
- The duty of care provision reaches beyond removals: once any city permit is issued, the holder must protect Significant Trees on the lot from harm, and failure that leads to a tree dying within two years can trigger both a fine and a mitigation payment.
- Large projects requiring certain special permits, and buildings of 25,000 square feet or more, must file a full Tree Study with the City Arborist at least 21 days before the permit application, and post a bond of at least $5,000.
- Green Cambridge runs a Canopy Crew program that plants native trees on private property for free — useful if you need Replacement Trees.
What we could not confirm
We would rather tell you what we don't know than guess. Call the office below to confirm these before you cut.
- — The dollar amount of the tree removal permit fee itself, as distinct from mitigation. Section 8.66.150 says only that "The fee for a Tree Removal permit shall be determined by the Commissioner of Public Works."
- — Review turnaround time — the city does not publish one.
- — Whether a tree under 6 inches DBH needs any approval at all. The ordinance defines Significant Tree at 6 inches and does not address smaller trees on private lots.
- — The full list of special circumstances. The city publishes them in a separate Tree Protection Ordinance Regulations PDF; the five most common are listed above but the complete list was not read.