October 11, 2016

Jackie Stanley
Department of General Services
2000 14th Street NW, 8th Floor
Washington, DC 20009

RE: Hearst Park and Pool Improvement Project

Dear Ms. Stanley,

Casey Trees is a Washington DC-based nonprofit, with a mission “to restore, enhance, and protect the tree canopy of the nation’s capital.” To fulfill this mission, we plant trees; monitor the city’s tree canopy; and work with elected officials, developers, and residents to prioritize the District’s trees and to encourage tree planting on both public and private property. We are dedicated to helping the District reach its 40 percent tree canopy goal by 2032. As a city, we will achieve this goal when development projects protect existing trees and plant new trees. Therefore, we are excited to provide comments on the Hearst Park and Pool Improvement project.

Community requests for the park’s new design include creating stormwater retention areas and preserving the park’s many mature trees. On September 8, Cox Graae & Spack Architects, along with the District’s Department of General Services and Department of Parks and Recreation, presented three design options for the park. These designs show the location of existing trees and placement options for a new pool and pool house. However, they do not show the true extent of the existing trees’ canopy or critical root zone (CRZ). Figures 1-3 below show the CRZ of existing trees. The CRZ must be protected in order to give mature trees the best chance of survival post-construction.

To ensure the trees at Hearst Park remain healthy, we recommend incorporating the following recommendations into the updated design proposal for Hearst Park:

1. Consider implementing the Option 1 design with some changes: Option 1 appears to affect the fewest existing trees. Ensure that security lighting, plumbing lines, and vehicular access have minimal impact on trees in the southeast area of Hearst Park. Consider using the opening between trees at the corner of Quebec and Idaho Streets NW as an access point for construction vehicles and pool service vehicles.

2. Preserve existing trees and replace trees lost during construction: Currently, Hearst Park has a 54% tree canopy. Adopt a 54% tree canopy goal for Hearst Park. To achieve this goal, preserve existing trees, and replace any trees removed at a 3 to 1 ratio.

3. Protect trees during construction: Adding tree protection fencing around any existing trees on or near the construction site will prevent damage from equipment and debris. We recommend installing metal fencing beyond the CRZ of these trees, as well as clear signage, as specified in the District Department of Transportation’s tree protection requirements (DWG NO. 608.10).

4. Prioritize shade trees: When selecting the new trees for this project, choose appropriate species based on available sunlight and rooting space to grow a healthy tree canopy. Where possible, prioritize large canopy shade trees to maximize benefits. Consider working with Casey Tees to establish a planting plan. Casey Trees’ Urban Tree Selection Guide is available for guidance.

5. Include trees in all bioretention areas: Any bioretention areas designed to manage stormwater runoff should include trees. Trees in bioretention areas further slow stormwater runoff and reduce pollution through interception, evapotranspiration, and nutrient removal. Casey Trees’ Urban Tree Selection Guide can be consulted to select trees that perform best in bioretention areas. Since Hearst Park has served as a stormwater drainage system for the neighborhood, maintaining existing trees and planting trees in bioretention areas will be essential for preventing flooding in the park after construction.

Thank you for the opportunity to comment. Casey Trees would be happy to work with you to achieve the suggested canopy goal, provide clarity on any of the above recommendations, or determine species selections for this site. If you have any questions, please feel free to contact me at ktaddei@caseytrees.org or 202-349-1892.

Sincerely,
Kristin Taddei
Planning Advocate

Figure 1: Hearst Park pool design proposal option 1 showing the true extent of tree canopy and the critical root zone of existing trees.

Figure 2: Hearst Park pool design proposal option 2 showing the true extent of tree canopy and the critical root zone of existing trees.

Figure 3: Hearst Park pool design proposal option 3 showing the true extent of tree canopy and the critical root zone of existing trees.

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