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Urban Forests, a living infrastructure, consist of private and public trees. Both need legal protection



Cambridge relies on Massachusetts General law to protect public shade or street trees. It also has Tree Protection Ordinance enacted in 2004 to protect certain trees on private property from removal or destruction. (Chapter 8.66 of the Municipal Code).  Sixty-four percent of the urban forest is located on private property (University of VT Urban Forest Canopy Assessment). These private property trees are performing a crucial public good to reduce the Urban Heat Island effect and a greater number need to be protected from wanton destruction or casual removal.

Several cities and towns in Massachusetts have some form of protection for private property trees. In Cambridge, the Tree Protection ordinance requires a "tree study" only for projects that require a special permit or where development will  be great than 25,000 square feet. Public housing projects or low-income projects are exempted from this ordinance. If the City arborist decides to allow trees to be removed, property owner can replant or place funds into a Tree Replacement Fund. This fund is separate from the general fund and can only be used to buy, plant or maintain trees in the city. Fund balance as of end FY15 was $78,000.

Other cities in Massachusetts have broader protection of trees on private property. Newton, for example, protects all trees on private property (4 or more units) with DBH (diameter at breast height ) of 8 inches or greater. It also protects tree from poisoning or damage due to excessive or improper pruning.  In Lexington, MA  trees with DBH of 6 or greater inches when it grows within a setback area (30 ft from front of lot and 15 ft on surrounding sides) are protected.  

This proposal is to modify the existing Tree Ordinance to protect high DBH trees on private property, a key part of the urban forest canopy. The criteria to remove private property trees with DBH greater than 6 inches will be strictly balanced against the need to protect a public good (mature tree canopy).

Category of the action


Who will take these actions?

Key action is by city staff and especially the Urban Forestry Department  in conjunction with the city council to expand the current ordinance to protect a greater number of trees on private property. This coverage should not exempt trees on state land, city land, nonprofit or institutional lands.  

Public hearings will be held to solicit feed back on details of proposed ordinance. This would including structure of deciding body, extent of coverage, enforcement & fines, determination of hardship and method of replanting.  Positive suggestions for best practices of mature tree care such as effective pruning and cabling can also be included. Legitimate safety hazards can be outlined to reduce frivolous reasons.  Also included could be protection for the sensitive drip line area of tree during construction.  Ailanthus and Norway Maples are generally viewed as invasive species however as mature trees they are a valuable part of the urban canopy and deserve protection.

Many organizations within the city may be interested in this revised ordinance including Public Planting Committee, Green Cambridge, network of community gardeners and horticulturists. 

If support aligns with this protection, an expanded ordinance will be enacted by the city council. 


What are other key benefits?

The protection of mature trees on public and private property will be instrumental as heat intensity is anticipated to increase (2030 Scenario from Kleinfelder report). In addition to reducing surface temperatures, trees provide additional benefit of wildlife habitat, stormwater management, privacy, reduction of energy consumption, esthetics, increased property values and general well-being. 

Benefit to having a broader private property tree ordinance is to have clear guidelines for tree care and removal only when necessary. In some cases where individuals claim trees are blocking their view or Sky rights, mature trees can be pruned to solve the perceived problem. In the instance where rooftop PV is installed prior to trees creating shade, regular pruning can solve the problem. Ordinance can also address instances where mature trees may prevent the installation of rooftop PV.

In my opinion, the public good provided by these trees outweighs private property rights. 

What are the proposal’s costs?

The cost to enact this municipal ordinance is staff and possibly legal consultant time. 

Negative side effect I can predict would be lawsuit brought by irate property owner who wanted to remove a mature, healthy tree protected by the new tree ordinance. The ordinance should be crafted in such a way to address problems frequently confronting strong private tree protection legislation.

Time line

I believe this ordinance would take one year to research and go through the public review process. It could become effective 6 months after enacted by the city council

Related proposals


Cambridge Municipal Ordinance Chapter 8.66

Newton Tree Preservation Ordinance Chapter 21, III Division 3

Lexington Tree Management Manual

Worcester Tree Adoption Program