Boston Tree Canopy Expands 150 Acres

This latest analysis is part of Boston's Urban Forest Plan, a 20-year strategy to create a more equitable and resilient tree canopy. The plan, initiated in 2022, specifically targets "priority zones" which are determined by overlapping factors including low tree canopy, extreme heat, environmental justice criteria, and historical redlining. The goal is to focus investment and improvements in these under-canopied and historically marginalized communities. The expansion of public tree cover is crucial as Boston battles the "urban heat island" effect, where dense concentrations of pavement and buildings absorb and retain more heat than natural landscapes. Some of Boston's neighborhoods can experience temperatures up to 40 degrees Fahrenheit warmer than surrounding suburban areas during heat waves. Research has shown that a robust tree canopy can significantly mitigate this, with shaded surfaces being 20 to 45 degrees cooler than unshaded ones. While the city celebrates gains on public lands, the recent assessment also revealed a loss of 116 acres of tree canopy on private residential properties. This highlights the critical role of private landowners in maintaining the urban forest, as roughly 60% of Boston's total tree canopy is on private land. Reasons for this loss include new construction and decisions by individual property owners. To address the loss on private land and promote equitable growth, the city, in partnership with Mass Audubon, runs the Boston Tree Alliance Program. This initiative provides grants and technical support to community organizations for tree planting and care on privately-owned land within environmental justice communities. In its third year, the program recently awarded over $519,750 to six community-based projects. The benefits of a single tree can be substantial. For example, one London Planetree in East Boston with a 24-inch diameter is estimated to conserve 1,843 kWh of energy, filter 3,244 gallons of stormwater, and remove 3 pounds of air pollutants annually. These services provide an estimated economic benefit of $117 each year, in addition to significant health and mental well-being advantages. The push for a larger and more equitable tree canopy is a key component of Mayor Michelle Wu's climate goals. To support the Urban Forest Plan, the city has established a new Forestry Division within the Parks and Recreation Department and has committed to hiring 11 new full-time staff members. This increased investment is aimed at clearing maintenance backlogs and accelerating planting and pruning schedules. The neighborhood-level data reveals a varied landscape of change. While Jamaica Plain saw the largest net increase of 21 acres, and the South End had the greatest percentage gain at 1.4%, Hyde Park and Mattapan experienced small net losses of tree canopy between 2019 and 2024. This detailed data helps the city to target future planting and preservation efforts more effectively.