Center City Philadelphia

TreeVitalize

TreeVitalize is a public-private initiative launched in 2004 to increase public awareness of the importance of community trees and reverse the loss of tree cover in Pennsylvania’s metropolitan areas. It is funded by the Commonwealth of Pennsylvania through the Department of Conservation and Natural Resources.

In the Philadelphia area, this program is led by the Pennsylvania Horticultural Society and is responsible for over 11,000 volunteers, 2,800 citizens participating in PHS Tree Tender courses and the installation of over 20,000 trees on public lands, as well as 300 acres of riparian buffer.

In 2008, TreeVitalize funded a special project focusing on Best Management Practices for the street trees along Chestnut Street in Center City Philadelphia. Originally installed in 1999, the paving within the tree trenches has shown signs of subsidence, and the trees are not thriving.

The CCD, in partnership with PHS and Lager Raabe Skafte Landscape Architects, is using this opportunity to study ways of retrofitting the existing trenches using various soil types and depths of soil in order to develop a Best Management Practice for the Chestnut Street tree collection.

As part of this study, trenches containing established trees have been retrofitted with one of two structural soil types— aggregate-based or sand-based. In several locations, existing declining trees have been removed and replaced, and the entire trench depth has been filled with one of the two soil types. In addition, some trenches have been treated with a hybrid reconstruction: part of the trench has been treated with a surface retrofit with the existing tree remaining in place, whereas the rest of the trench has been treated as a full-depth installation with a new tree planting. Over the next several years, the trees and pavers at all locations will be monitored on a bi-monthly basis in order to determine the soil type which most successfully supports tree vitality and maintains the structural integrity of trench pavers in this urban environment.

The map below shows locations of each test trench, and details the treatment of the trench and the tree species. Results of the monitoring will be updated on this site at regular intervals throughout the year.

View CCD TreeVitalize Project in a larger map