Arlington tree ordinance explainer

When Article 16 applies

• Arlington’s Tree Protection and Preservation Bylaw (Article 16) applies to three situations: demolition of an existing structure, construction that increases total building footprint by 50% or more, and new construction on a lot with no existing structure.
• If one of those triggers is met, a Tree Plan must be submitted to the Tree Warden before or at the same time as the building or demolition permit application.
• The bylaw does not apply to public shade trees, which remain on a separate Chapter 87 track under the Tree Warden’s jurisdiction.

What counts as a Protected Tree

• In Arlington, a Protected Tree is any existing healthy tree on private land with a DBH of 6 inches or greater in the setback area.
• Older summaries and secondary sources may still refer to an 8-inch threshold. Arlington’s current bylaw language and current Tree Construction Guidelines use 6 inches DBH.
• The setback area is defined by the minimum front, side, and rear yard depths under Arlington’s zoning bylaw.
• Trees that pose an immediate hazard to person or property, or are under imminent threat of disease or insect infestation, are excluded from the Protected Tree definition.
• For multiple-trunk trees, DBH is measured as the aggregate diameter of the trunks at 4.5 feet above grade.

The 12-month lookback

• If Protected Trees were removed during the 12 months before a building or demolition permit application, those trees must still be shown on the Tree Plan and mitigated as though they were part of the current project.
• Arlington built this as an anti-gaming provision. Clearing trees before filing does not avoid the mitigation obligation.

What the Tree Plan has to show

• The Tree Plan must be drawn and stamped by a certified land surveyor or engineer and also stamped by a certified arborist or landscape architect.
• It must show all Protected Trees in the setback areas and any nearby public shade trees.
• For each tree, the plan should identify species, size, critical root zone, and proposed disposition: retained, removed, or protected during construction.
• For each Protected Tree to be removed, the plan should identify the applicable mitigation fee.
• The plan also needs to show how the critical root zones of retained Protected Trees and nearby public shade trees will be protected during site work.
• Arlington requires a $50 filing fee with the Tree Plan.

Mitigation

• For each Protected Tree removed, payment is made to Arlington’s Tree Fund before work begins.
• Arlington’s published Tree Construction Guidelines use $375 per inch DBH as the current mitigation figure.
• Because the bylaw says the mitigation rate is set by a Select Board schedule, confirm the current rate with the Tree Warden before filing.
• Arlington’s bylaw uses Tree Fund payment rather than private on-site replacement as the mitigation path.

Critical root zone protection

• Arlington defines the critical root zone (CRZ) as 1 foot of radius per 1 inch of DBH.
• The town’s construction guidelines show three standard protection methods depending on the situation: fencing around the CRZ, mulch and mats when vehicles must cross the CRZ, and trunk/buttress-root wrapping when the tree is close to structures or hardscape.
• The Tree Warden has access to the site during normal business hours to verify compliance with the approved Tree Plan.

What happens without an approved Tree Plan

• Removing a Protected Tree on an applicable site without prior written approval can trigger a fine of $300 per day of work, plus additional fines for each Protected Tree removed.
• Removing a Protected Tree not identified for removal in an approved Tree Plan carries a $300 fine per tree.
• Failure to complete required mitigation carries a $300 per day fine until mitigation is achieved.
• For willful violations, Arlington can also seek injunctive relief in court.

Where Arlington files go wrong

• The first common mistake is not realizing Article 16 applies. A 50% footprint increase on a modest lot can be triggered by an addition that does not feel like a major project.
• The second issue is the 12-month lookback. If prior removals are not checked early, mitigation cost appears late in the permit path.
• The third issue is the Tree Plan itself. Arlington expects a stamped plan with CRZ protection methods; a loose sketch or landscape concept is not enough.