Private properties when sold can come into new ownership that may tear down and replace, or significantly expand on, the footprint of the existing dwelling.  Alternatively, a propertly that formerly had a single family home on it may be converted to multi-family dwellings. These projects often lead to significant private tree removal and sometimes clear cutting a site.

Natural gas causes trees to decline and can lead to tree mortality. Brookline's natural gas infrastructure is aging and is often difficult to replace/restore.

Projections indicate that as Brookline's climate changes, certain tree species will be susceptible to extreme temperatures (both hot and/or cold). The increased frequency and severity of storm events also pose a threat to trees, as strong winds and heavy precipitation may lead to windthrow and tree failures. We anticipate the introduction of new invasive pests and diseases, the alteration of suitable habitat for local fauna, and changes in key ecosystem processes.

The Town has a Forestry function within the Parks and Open Space Division that has certified arborists on staff that prune, assess and care for Brookline's public trees.  These are the trees that are along the public streets, within parks, school grounds, cemeteries and other Town properties.  There are estimated to be approximately 50,000 public trees in Town. 

Trees need robust root systems to support their growth and development over time, and the volume of soil available to a tree is an important factor in its ability to grow a healthy root system. To sustain Brookline’s existing trees and plant additional trees to enhance the canopy, Brookline must provide large volumes of soil for roots to grow. Soil volumes are limited along streets and within semi-urban environments.

Brookline's trees are currently susceptible to several pests and diseases, including the Emerald Ash Borer, Winter Moth, Hemlock Woolly Adelgid, and Dutch Elm Disease, which cause significant damage to certain tree species and may result in tree mortality. 

Eversource and telecommunication wires on above ground utility poles may conflict with the development and care of public and private trees.

Brookline property values remain high, and land is in great demand for commercial/institutional development. These projects often lead to significant private tree removal and sometimes clear cutting a site.