The notion that the answer to climate change is to plant trees is naive. Million- or billion-tree campaigns may be attractive in their simplicity, but without proper maintenance, many trees struggle to survive. However, a healthy urban forest can be an ally in the effort to make our cities more habitable in the face of atmospheric extremes—helping slash temperatures, sequester carbon, and absorb runoff (a single sizable tree can manage stormwater from 2,400 square feet of impervious area, according to the EPA).
It is especially worrisome, then, that urban trees themselves may be victims of a shifting climate. Rising temperatures, particularly in cities, are predicted to alter the spatial distribution of many species. The ranges of more sensitive tree species are already migrating farther from the equator as average temperatures rise, and drought and other factors could cause further stress, making trees more susceptible to pests and disease.
An experimental forest planted as part of Cambridge, Massachusetts’s new Triangle Park is an attempt to reckon with these challenges. Designed by Stoss Landscape Urbanism, the park is located in Kendall Square, where the urban canopy cover is currently below the city average. Along with a shaded seating area, sloped lawns, and a wooden stage, the landscape packs 400 new trees onto what was previously a forgotten traffic island. As the forest grows and evolves, some trees naturally will be outcompeted. This is intentional: “It’s replicating the natural succession [of a forest],” explained Albert Chen, an associate at Stoss. The idea is to let nature take its course and for the trees best suited to Cambridge’s urban environment to reveal themselves over time. Saplings that fail to thrive will be culled. “It’s an active intervention,” Stoss’s founder, Chris Reed, said. The competition is also beneficial from a climate perspective, as rates of carbon sequestration correlate with a tree’s rate of growth.
Acquired by the city through a development deal that also provided funding for park design and construction, Triangle Park is a green island hemmed in by three roadways, 20th-century apartment blocks, and new mixed-use developments. In addition to providing public open space, the park serves as a demonstration site for Cambridge’s Urban Forestry Division, which is focused not just on the size of the urban forest but on its health and ecological resilience. “This was a great opportunity for Public Works to show other city departments some of the recommendations that we’re looking at implementing moving forward,” said Andrew Putnam, director of urban forestry.
Triangle Park was originally destined to become a less vegetated plaza. But the completion of the city’s Urban Forest Master Plan in 2020 put the park on a new trajectory. Having identified East Cambridge and Kendall Square as a priority area for increasing canopy, the city asked Stoss to scrap its plans and instead prioritize trees. “These designs sort of collided,” said Kathy Watkins, commissioner of public works. “Because it wasn’t an existing open space that had programmed uses, there was a real opportunity to really flip [the] script and have it be more about the urban forest.”
Following the shift, the team “immediately started asking, what’s the role of people?” Reed said. “How can we meet the goals of the urban forestry plan but take into account that people are part of this?”
The park is loosely divided into three habitat zones inspired by plant communities native to New England: a lowland forest, an upland forest, and a midland forest. Located at the triangular park’s southernmost vertex—the site’s natural low point—the lowland forest is full of moisture-tolerant tree species and collects runoff from the rest of the site. Along the park’s busy eastern edge, the upland forest uses hundreds of bare-root saplings planted atop a 5-foot-high berm to create a living buffer that in turn shelters the third habitat zone: an urban grove of rare multistem Kentucky coffee and birch trees. The grove also boasts flexible seating, creating what the designers call the “social nucleus” of the park.
In its density, its emphasis on biodiversity, and its more ecological approach to management, Triangle Park signals a true departure from the conventions of urban forestry. The planting design is informed by the Miyawaki method, an approach to afforestation developed by the late Japanese botanist Akira Miyawaki that prioritizes native and adaptive species planted in dense clusters to promote rapid growth. It’s very different from the way most American cities have thought about tree-planting efforts.
“There was a period of time where every project in America was subject to that city’s very small list of successful urban street trees,” Reed noted. “[Triangle Park] is really rethinking that.” The push to rethink traditional planting approaches came as much from the city’s staff as it did from Stoss, Reed added. “We’ve never had a client like that, who’s pushing us as much as we’re pushing them.”
Triangle Park is not the city’s first Miyawaki forest. Initiated by two nonprofits, the SUGi Project and Biodiversity for a Livable Climate, a 4,000-square-foot public woodland modeled after the Japanese method was established in Cambridge’s Danehy Park in 2021. Located on the west side of the city amid a sprawling, 50-acre recreation complex, Danehy Park is less a part of the urban fabric, however. Triangle Park represents the application of the method on a compact urban site in an extensively developed neighborhood.
Though Triangle Park is a test, Stoss’s rationale for a more resilient forest supersedes the functional: Reed pointed to the mental and emotional benefits of biodiversity, as well as the potential for personal experiences in nature to create more environmental awareness.
“Biodiversity loss within urbanized environments is off the charts,” Reed said. “The question is, how do you start to think about replenishing that? And the simple version is [to replicate] an experience that [a person has] had in some sort of an environment— whether it’s canoeing in a marsh or hiking in the woods.… It’s the experiential piece of somebody’s connection to the environment and the impact that might have on their thinking and the way they live their lives.”
Timothy A. Schuler is a writer and design critic whose work has been published in Metropolis, Bloomberg CityLab, Landscape Architecture Magazine, and Places Journal.
