By Doris Jenkins
What is Tree Equity?
American Forests, a non-profit conservation organization dedicated to protecting and restoring healthy forest ecosystems, defines “tree equity” as having enough trees in an area such that everyone can experience the health, climate, and economic benefits that they provide. A thriving urban forest can reduce urban heat island effect, contribute to human comfort, enhance air quality, mitigate stormwater flooding, and increase the health and happiness of residents. Healthy and thriving urban forests can also help reduce energy costs at adjacent properties; provide ecosystem services; support habitat connectivity; create more comfortable outdoor commercial areas, public spaces, and parks; and increase the overall aesthetics of a city by introducing more greenery. The first step towards achieving tree equity, however, is identifying canopy gaps in vulnerable areas, followed by resilient planting plans.
Identifying Tree Canopy Gaps
On a bright, sunny day this past September, several students from the “Climate Crisis and Society” class at the University of Massachusetts Lowell (UML) could be seen wandering the streets of the city, eyes to the sky. While passersby may have thought they were merely students with their heads in the clouds, they were in fact students with their heads in the trees. The focus on Lowell’s trees came about due to a grant that the City of Lowell received through the Massachusetts Executive Office of Energy and Environmental Affairs’ (EEA) Municipal Vulnerability Preparedness (MVP) Program. According to its website, the MVP Using Grant Funding to Promote Tree Equity in Lowell by Doris Jenkins, Weston & Sampson program provides support for cities and towns to begin the process of planning for climate change resiliency and implementing priority projects. In this case, the city is using the grant to help complete its first ever Resilient Urban Forest Master Plan.
Healthy and thriving urban forests can help reduce energy costs at adjacent properties; provide ecosystem services; support habitat connectivity; create more comfortable outdoor commercial areas, public spaces, and parks; and increase the overall aesthetics of a city by introducing more greenery. The first step towards achieving tree equity, however, is identifying canopy gaps in vulnerable areas, followed by resilient planting plans.
UML students from a variety of majors such as environmental science and engineering, sociology, and criminal justice began by participating in a lecture on how urban forestry and climate justice are intertwined with each of their prospective careers. Following the presentation, they took part in on-the-ground tree inventory training. Using a plant identification application and ArcGIS Survey123, the students collected GPS coordinates of trees throughout the city, along with information such as species, diameter at breast height, and planting space condition. This effort resulted in over 250 data points which were field verified by trained city and consultant staff.
In Massachusetts, an environmental justice (EJ) population is a neighborhood where one or more of the following criteria are true: 1) the annual median household income (MHI) is 65% or less of the statewide annual MHI; 2) minorities make up 40% or more of the population; 3) 25% or more of households identify as speaking English less than “very well”; 4) minorities make up 25% or more of the population and the annual MHI of the municipality in which the neighborhood is located does not exceed 150% of the statewide annual MHI. Lowell has significant EJ populations, often overlapping geographically with areas that have minimal forest canopy and thus experience the more intense effects of urban heat islands. Urban heat islands occur in heavily developed areas with large amounts of impervious surfaces such as paved roads, parking lots, and buildings that absorb and retain heat, often with minimal relief from shade trees. The goal of this Resilient Urban Forest Master Plan is to understand the condition of the existing urban forest, identify geographic regions with EJ populations or critical infrastructure like community centers and transit stops, and create a planting and maintenance plan that will promote tree equity and help mitigate negative climate impacts.
Too often, trees that are planted with good intentions die shortly thereafter due to poor site conditions and a lack of water. By assessing site conditions prior to planting, such as available space, soil type, surrounding pervious or impervious surfaces, and topography, it is possible to make educated planting decisions that increase a sapling’s chances of survival. Understanding what species are best suited to a given location, as well as the maintenance capacity of the staff at that location, is crucial for growing a resilient urban forest. Species diversification also increases the resiliency of an urban forest by preventing monocultures that can be wiped out by a single blight.
In a time when climate resiliency is at the forefront of everyone’s minds, focusing on urban forests can offer communities a great starting point. Using native species and incorporating stormwater management into tree plantings can maximize the potential of small greenspaces while simultaneously reducing operations and maintenance needs.
Doris Jenkins is an ISA-Certified Arborist and Engineer with Weston & Sampson’s climate resiliency team. Based in Boston, she provides technical assistance for urban forest resiliency plans, climate baseline and projection analyses, and state-wide resilience standards development. Doris can be reached at firstname.lastname@example.org.
Published in Massachusetts Planning, January 2023.