Davey Tree Flipbooks

T he quaint, colonial ambiance of New Haven, Conn., exemplifies the town's rich history and traditional charm. Visitors may stroll along the pedestrian-friendly streets to explore New Haven's many dining options, impressive art galleries and historical landmarks. Although the traditional architecture defining the value of old homes and buildings draws the attention of passersby, New Haven's legacy trees earn recognition for their sheer size and existence along the city streets as well. In 2009, the Greater New Haven Water Pollution Control Authority (GNHWPCA) needed to update the existing sewer system along Trumbull Street—New Haven's main artery into downtown and Yale University campuses—to separate storm water from sewage and reduce necessary water treatment. However, construction threatened the integrity of several large trees. But a bit of innovation and attention to detail solved the city's dilemma and achieved its goal: Preserve most of the special trees that have witnessed the growth and development of New Haven for many years. The unique perspective Davey Resource Group applied to the preservation of Trumbull Street's trees earned much respect and recognition—and two awards. ALL ON BOARD. Davey began working on the proposed Yale Campus/Trumbull Street Sewer Separation Phase 1A Project more than four years ago, when Cardinal Engineering Associates contracted Davey to provide an in-depth analysis of the potential impact to all trees within construction limits. "The con- tractor Fucci Construction hadn't looked into tree preservation and assumed the trees would have to be removed," explains DRG Senior Consulting Urban Forester Allan Fenner. Maintaining the integrity of Trumbull Street and the surrounding area's trees was a significant concern within the community. At first, Fucci Construction slated the trees for removal. When officials reviewed the project's plan again, however, it was evident the trees' untimely fate could be avoided. "Cardinal Engineering hired Davey to develop our plan to preserve the trees," Fenner says. Davey's Chris Cowles, Cary Hulse and David Zeitlin also contributed to the project's design, which required traditional excavation on private properties along Trumbull Street and solicited a new approach to tree preservation. Davey completed several facets of the project, including a detailed tree inventory of all trees within proposed construction limits; design analysis and consulting with project engineers; attending and presenting at public meetings; and developing tree preservation plans and specifications. Inventory results determined nearly 90 trees existed within construction limits. "Due to the size of the majority of the trees, traditional above-ground excavation would lead to their removal," Fenner explains. Because no records exist to indicate where the tree roots grow, Davey convinced Fucci Construction and GNHWPCA that the best method to determine viable options would be to conduct a root inspection with Ground Penetrating Radar. "We used Ground Penetrating Radar to determine the depth and mass of roots below the street," Fenner says. Upon reviewing results and to ensure the least impact to the trees, Davey recommended pipe jacking, in which the crew digs one hole to push large pipes to the side and below the tree roots to cause minimal disruption within the root system. "Pipe jacking was more costly than the traditional approach, but we achieved our goal to preserve the trees, which was a necessity," Ricozzi says. "It worked out well." Ricozzi was impressed by Davey's solutions. "The tree preservation plan Davey put together essentially treated the roots as utility service elements, which is something that hadn't been done before in New Haven," he says. IMPRESSIVE INNOVATION. Davey's tree preservation project succeeded in ensuring the large roots of several trees would survive. Many mature trees stood within the route of the sewer project—trees that had survived two recent major storm events— so maintaining the trees' canopy cover and contribution to stormwater retention rates was important to surrounding residents and community members. "Only six trees had to be removed for construction, when initially 54 trees would be," Fenner explains. Davey also planted 30, 3-inch caliper trees to adhere to New Haven's caliper replacement guideline for construction projects. Ultimately, Fucci Construction's project manager appreciated the collaboration and execution of the project, adding it was better than imagined, saving the team a lot of money at the time. "In the beginning of the project, Fucci Construction looked at trees as ob- stacles," Fenner explains. "But now, their team realizes trees can help manage stormwater runoff in the city." As Ricozzi says, "we were fortunate to have the opportunity to work with Allan and Davey." DESERVED RECOGNITION. The two American Society of Civil Engineers (ASCE) awards Davey's team earned include a merit award in the construction category and first place in the water resources/environmental category. Davey's successful contributions to Phase 1A of the project have earned them involvement in a similar GNHWPCA sewer separation project. As Fenner says, "New Haven's community knows the benefits of trees." Legacy Trees Warrant Extra Measures Davey's efforts in a New Haven tree preservation project earn the team not just one—but two—awards. 8 | January/February 2014

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