“The integration of Silva Cells… allowed us to achieve transportation modal accommodation for pedestrians and bikes, while also providing the infrastructure underneath this hardscape for a healthy urban tree environment.”
Situated between 30th Street and Pearl Parkway in Boulder, Colorado, the area now known as Boulder Junction had historically been an industrial sector; however, with the addition of numerous neighborhood startups, it became obvious that connected, pedestrian-friendly infrastructure was required — and an ambitious renovation project was launched in 2013. Urban forestry enhancements were incorporated into this community-first initiative, though the space in which the 29 new trees were to be planted was significantly constrained due to parking and transportation requirements. Recognizing the need to provide a healthy, sustainable environment for flourishing tree growth, the design team selected the DeepRoot Silva Cells to help properly optimize the limited space.
Number of Silva Cells: 1,249
Amount of Soil Volume Per Tree: 430 ft3
Number of Trees and Type: 29
Type of Project: Trees, Streetscape
Project Designer: City of Boulder and Tsiouvaras Simmons Holderness
Project Timeline: 2013-2015
Boasting a lineage of sustainable, community-friendly growth, Boulder, Colorado, is a vibrant town located at the base of the Rocky Mountain foothills. The town’s central geographical area, situated between 30th Street and Pearl Parkway, had for years been an industrial neighborhood with little in the way of welcoming streetscapes and environmentally conscious infrastructure. As the local business community began to grow, however, it became clear that neighborhood improvements would be required — thus, a multi-phase renovation initiative broke ground in 2013.
To make the area more livable and walkable, the redevelopment plans paired multi-modal transportation infrastructure with innovative urban treatments (including urban forestry enhancements). The project involved construction of a new multiway boulevard on the south and north sides of Pearl Parkway with the ultimate goal of incorporating all modes of travel: pedestrians, bicyclists, and cars.
Another major project priority was to create a welcoming “place” for the residents that included 29 streetscape trees — an urban forest intended to serve as an inviting environment for locals as well as a mitigation solution for the heat island effect experienced in the hot summer months. Because a number of new design elements were competing for right-of-way space, including a high-density residential unit with a prominent ground-floor presence, project developers needed to find a way to make the most of their limited area, and they selected DeepRoot Silva Cells to help with the healthy growth of the street trees.
The design team recognized the importance of integrating a sustainable environment for the trees into the urban design, to complement the overall public space and infrastructure design. By incorporating 1,249 Silva Cells in the project, the trees were given adequate uncompacted soil volume to continue to thrive, while the impact to the paved area above ground remained untouched.
“We recognize the positive contributions of healthy urban forestry assets as a basic part of the transportation infrastructure — like good drainage, durable pavements, or multi-modal transportation,” observed Alex May, Transportation Project Manager for the City of Boulder Public Works Department. “The focus on enhancing the public space with a healthy tree canopy contributes to the overall quality of the project and the urban environment.”
He goes on to note that “the significant space limitations eliminated the ability to have open and wide planter areas, as the designers needed to utilize all available space for roadway, parking, and bike and pedestrian facilities. The integration of the Silva Cells under our multi-use path hardscape improvements allowed us to achieve transportation modal accommodation for pedestrians and bikes, while also providing the infrastructure underneath this hardscape for a healthy urban tree environment.”
Both sides of Pearl Parkway incorporated Silva Cells into their design, using 1X and 2X system arrangements depending on the presence of preexisting utilities. The project’s first phase was a huge success, and the second phase, located just west o the railroad tracks, shows equally robust plant response.