New Protections For Philadelphia's Heritage Trees

Several coding exceptions have limited protections for Philadelphia's existing canopy. Now, Philadelphia is trying to make up for its losses.

Current Laws Limit Protections for Heritage Trees

What defines a heritage tree varies across public entities, but generally, it is a tree that exists on a property pre-development. Identifying a heritage tree protects it from removal for construction without a permit and may require replacement if a heritage tree is removed. This aims to prevent or mitigate the loss of trees that contribute to a city's green infrastructure.

Philadelphia's tree code states that heritage trees are not to be removed from a property, but there are exceptions. A heritage tree in Philly is at least 24 inches in diameter - unless it is an American Chestnut (this tree is protected at any size). Furthermore, a tree can only qualify if it is native or considered important. Philadelphia's zoning laws dictate that only heritage trees on properties above 5000 sq. ft. are protected.

Even if a tree meets all the conditions above, this does not mean it will not be cut down. In section 14-705 of Philadelphia’s zoning ordinance, many exceptions allow a heritage tree to be removed. Special exception approval is needed to cut down any heritage trees. Unless it is being replaced by a tree defined by Tree Replacement Requirements [14-705(1)(g)]. Protections of a heritage tree are revoked if a written proposal promises to replace the tree with a new tree of equal diameter size. It will take years for the replacement tree to reach the same level of maturity of what it replaced. Therefore, the quality and type of ecosystem services the previous tree provided may be unmatched in the years it takes for the next tree to grow.

Even location of a heritage tree may not be enough to protect it. Trees can be removed if a development proposal cannot be feasibly redesigned around a heritage tree. Trees existing on single-family, two-family, and urban agriculture lots are excluded from protection. Trees located on lots under 70 acres or located 75 feet away from streets and specific districts (for example, commercial, mixed-use, and residential) are not protected either.

Despite of laws meant to restrict the removal of heritage trees, enforcement has not always been effective. In recent years, businesses have removed acres of trees without classifying potential heritage trees. Therefore, issuing citations for stumps that were never identified in the first place is an impossible task. In such cases, Philadelphia’s Department of License and Inspections is ill-equipped to enforce protection of heritage trees, nor is it a high priority to do so. As an investigation into heritage tree law violations by Grid Magazine states, “Like most municipal tree codes, Philadelphia focuses on documenting and then replacing trees rather than protecting them from being cut down in the first place.”

Different regions of Philadelphia have different levels of tree cover. Increasing tree cover and expanding protections for already present trees will have meaningful impacts on the community and Philly's urban canopy. Photos from Philly Tree Plan (left photo by Raymond Perez and right photo by Abdul Anderson).

The city’s exemptions have made the protection of heritage trees a hairy endeavor. Loose protections for heritage trees translate into restrained protections for the rest of Philadelphia's urban canopy. These limitations have contributed to major losses in the city's tree cover.

In the past decade, Philadelphia has lost 6% of its urban forest. That loss of tree cover is equal to an area of 1,000 football fields. The remaining tree canopy covers only 20% of the city, and the distribution of this tree cover is not equal. In some areas, tree cover is as low as 5%. Communities living in these places are unfairly cut off from the beneficial services and hazard relief provided by the urban canopy (Philly Tree Plan, 2023).

This map provided by the Philly Tree Plan demonstrates regional changes in the urban tree canopy over the last decade.

A section of Allegheny Avenue in Philadelphia without tree cover. Photo from Philly Tree Plan.

A New and Improved Future for Philadelphia's Urban Forests

To address tree cover losses and create more equitable access to tree services, Philadelphia has developed the Philly Tree Plan. This extensive 10-year plan defines eight goals to improve the urban canopy while uplifting the voices and well-being of the community. The second main goal is to protect the existing and future urban forests.

Under current heritage tree laws, protecting native species with a minimum diameter of 24 inches is conserving few trees. According to the USDA Forest Service, only 6% of trees in Philadelphia met those diameter requirements. As a result, many non-heritage trees are liable to be cut down for development without replacement. These heritage laws are problematic for the preservation of Philly's existing urban canopy.

To expand protections for city trees, the Philly Tree Plan aims to lower the diameter minimum needed to qualify for a heritage tree. This will grant smaller-diameter trees greater protection. As most Philly trees are under 24 inches in diameter, smaller trees contribute significantly to the city's green infrastructure.

Many trees in Philly are not native, so future heritage tree laws should be expanded to include more species. Lot size minimums should be lowered and protection exemptions (like the exclusion of single-family and two-family lots) should be revoked. By expanding what is protected as a heritage tree, these adjustments will reduce future losses to Philly’s urban canopy.