City Ridge Heritage Tree and Special Tree Transplanting and Preservation

Three enormous trees rolled along Wisconsin Avenue in Washington, D.C. to their new home in January 2019. WSSI’s Tree Preservation Specialists began planning more than a year before the tree relocations and stuck with the trees after their journeys and transplanting, working with the design, construction, transplant, and maintenance teams to ensure the trees thrive.

The Challenge

The well-known Fannie Mae site in northwest D.C. was slated for multi-use redevelopment, but updated D.C. urban forestry regulations presented the project team with three challenges in the form of a 35” DBH Heritage-sized willow oak, a 36” DBH Heritage-sized pin oak, and a 28” DBH Special-sized northern red oak.

Washington, D.C. updated urban forestry regulations in 2016 requiring all non-government projects to save Heritage Trees[1] and Special Trees[2] in place or relocate them to a “safe” spot. Additionally, these regulations also stipulated that a tree transplant candidate be root pruned (cutting off approximately 80% of the roots), then watered and nurtured for at least a year to ensure it can withstand the shock.

This high-profile project was the first effort to relocate trees under the 2016 regulations, and it received a great deal of attention. (If trees rolling along Wisconsin Avenue won’t get attention, what will?)

[1] 100” or more trunk circumference (DBH (diameter at breast height) of more than 31.8”)

[2] 44-99.9” circumference (14-31.8” DBH)

Our Solution

WSSI staff used ground-penetrating radar to evaluate tree roots under pavement and created a visualization of root density in CAD to inform construction processes. Our specialists prepared the roots of the heritage and special-sized trees for transplant with fine-tuned irrigation practices and regularly inspected each tree’s condition before the transplanting. Meetings with engineering, construction, and landscape design firm personnel ensured clear communication and effective tree protection for the move and in their proposed destinations. After successfully relocating the trees, with their 35-foot diameter root balls and 70-foot-wide crowns, WSSI collaborated with the team to ensure the transplanted trees and other trees on the site could thrive. WSSI also provided erosion and sediment control consulting and inspections during the project construction to support stormwater management and environmental protection.