What Lexington regulates
- Lexington’s bylaw applies to protected trees that are 6 inches DBH or larger in the setbacks of properties undergoing demolition or major construction.
- The trigger is not every tree on every lot. It is tied to demolition, new construction, or a 50% or greater increase in building footprint.
- Multiple-trunk trees can also qualify when the combined trunk size reaches the bylaw threshold.
What has to be submitted before construction
- A plot plan showing setback lines, protected-tree size and location, and which trees are proposed for removal.
- A Tree Removal and Mitigation Permit application through Lexington’s online portal.
- A Tree Protection Plan prepared by a Certified Arborist for retained protected trees and any Town trees in the right-of-way.
If exemption from mitigation is claimed for a dead or hazardous tree, Lexington also requires:
- An ISA Basic Tree Risk Assessment Form
- An arborist attestation
- Photographs showing the full tree and the hazardous or dead condition
Tree Save Area and protection standards
- Lexington’s Tree Save Area is the drip line or 1 foot per inch DBH, whichever is greater.
- Protective fencing must be 5 feet high or higher chain link or welded wire on stable metal posts.
- The town requires English and Spanish signage on the fence.
- If the Tree Save Area must be reduced, root pruning or other protective work has to be handled by or under the supervision of a Certified Arborist before site work begins.
- Lexington prefers tunneling to root pruning where feasible and expects updated protection documents if field conditions change.
Mitigation math
- Trees under 24 inches DBH are generally mitigated at 1 replacement inch for each inch removed.
- Trees 24 inches DBH and larger are mitigated at 4 replacement inches for each inch removed.
- Planting standard mitigation is 1 inch of new caliper for each replacement inch owed.
- Planting from Lexington’s Large Shade Tree List gets a 4x credit, meaning 1/4 inch of planted caliper can satisfy 1 replacement inch.
- Any remaining balance can be paid into the Tree Fund at $200 per replacement inch.
- Lexington also charges a $20 per inch permit fee for protected trees removed.
Street frontage planting matters
Lexington does not treat mitigation as a purely private-lot exercise. If there is a large gap in street-frontage canopy and suitable planting space exists, frontage planting has to be satisfied before off-frontage mitigation planting or in-lieu payment gets full credit.
Survival obligations
- Retained protected trees and mitigation plantings must survive for 1 year after the certificate of occupancy.
- If a retained protected tree dies in that period, the property owner owes mitigation.
- If a mitigation planting dies in that period, it must be replaced within 9 months.