Northampton draft narrows DBH threshold, doubles replacement ratio for trees removed in some zoning districts

Carolyn, a city planning staff member, presented proposed changes to Northampton's tree-replacement rules at the Urban Forestry Commission's April 2 meeting, saying the draft seeks to expand which removed trees trigger replacement requirements and to tighten how replacements are calculated. "The tree replacement requirements are triggered currently for projects ... that would remove trees more than 20 inches at DBH," Carolyn said, describing the current standard and the proposed revisions.

The draft would replace the single 20-inch DBH threshold with a table of thresholds that vary by zoning district and would increase the look-back period for prior removals from 12 months to 18 months. Under the proposal, triggers would include: 17 inches in the central business/downtown district; 15 inches in urban residential zones around Florence Center; 12 inches in highway/general business districts; 10 inches in suburban residential zones; and 6 inches in special conservancy and farms/forests/rivers districts. The draft also requires a certified arborist's assessment, including specified qualifications for tree-risk evaluation, for trees inside and within 10 feet of a project's work-limit line.

Carolyn said the draft also changes the replacement calculation. "So this would be a 1 to 1. So if I take down 40 inches instead of planting 20 inches I have to plant 40 inches," she said, referring to a shift from the current payment-or-planting standard (one-half the removed DBH in inches) to a full one-to-one replacement or equivalent payment. The draft includes an option for payment-in-lieu; the draft itself does not fix the dollar-per-inch amount in the ordinance but leaves that figure in an administratively maintained schedule.

Other proposed specifics in the draft include planting density language (one new tree per 25 feet of frontage where exemptions apply) and clearer submittal requirements for projects coming before the planning or zoning boards. Carolyn said the change is intended to capture trees that are damaged by construction even if they lie just outside an illustrated work-limit line, which she said have historically been missed by applicants and contractors.

Carolyn showed a city map used to justify different thresholds by district and referred commissioners to a consultant's carbon-impact calculator. She said the tool compares the one-time carbon release from tree removal and embedded carbon in demolished structures with the long-term vehicle-miles impact of building in outlying locations. "The overwhelming calculations show ... the on-road impact of vehicles is that much greater than building in the core neighborhoods," she said, summarizing the consultant's preliminary results.

Commissioners raised several substantive points: Kent (incoming member) and others urged the commission to consider heat-island data and the particular value of large canopy trees in downtown heat islands; Commissioner Jen and others asked whether planting in sidewalks or structural-soil systems should be encouraged for downtown tree resilience; and Commissioner Molly asked how planning exemptions (for permanently protected open space or affordable housing paired with net-zero buildings) would be evaluated and whether a minimum acreage should be required. Carolyn and chair Rich Parasolidi responded that planning-board discretion is built into the draft for some community-benefit allowances and that the draft intentionally left certain implementation details (such as the dollar amount for payments-in-lieu and the city's planting-guidelines updates) to administrative schedules or referenced documents so they could be updated without re-amending the ordinance.

Rich Parasolidi and several commissioners expressed general support for moving the draft forward to public review while noting remaining questions about downtown canopy protection and about how the proposal would affect small-scale or affordable developers. Rich said the commission will collect written questions and forward them to Carolyn for responses prior to the commission's next meeting.

Votes at a glance

- Motion to accept minutes (procedural): Moved by Molly; second not specified. Roll call: Rich Parasolidi: yes; Molly: yes; Jen: yes; David: yes; Richard Parish: yes. Outcome: approved. - Motion to adjourn: mover and seconder not specified. Chair called for all in favor; no abstentions. Outcome: approved.

Ending: Carolyn noted the draft still must proceed through the city's review path (planning board, city-council public hearings and eventual council vote) and welcomed written follow-up questions. Commissioners agreed to place the item on the commission's next agenda for a formal advisory vote to the mayor and council.