Despite efforts to increase Philadelphia’s tree canopy, the city has lost the equivalent of 1,000 football fields worth of leafy shade in the last 10 years.

So the city is creating a 10-year Urban Forest plan to reverse the trend. The effort begins Thursday with a citywide “Tree Summit” at the Discovery Center in East Fairmount Park — a gathering of arborists, educators, and community leaders organized by Philadelphia Parks and Recreation and the Office of Sustainability.

The announcement comes on the heels of a decade-long look at how the tree canopy — a measurement of the layers of leaves, branches, and stems trees provide — fared from 2008 to 2018. The report shows a decline along city streets and on residential land.

“We’re trying to target areas that have the most need for trees and are the most vulnerable,” said Erica Smith-Fichman, Philadelphia’s community forestry manager.

Trees help mitigate the impact of climate change, reduce the urban “heat island” effect that makes some parts of the city hotter than others, and provide beauty.

Overall, the Tree Canopy Assessment Report released this week found that the city gained 1,980 acres of tree canopy in the 10 years studied, but also lost 3,075 acres. Much of the loss came from the removal of trees that line streets.

To create the report, the city commissioned the University of Vermont Spatial Analysis Lab, which used aerial imagery, light detection, and ranging (LiDAR) data.

Tree canopy now covers only about 20% of land within the city, the report states. The goal is to increase that to 30%.

The relative tree canopy change percentage shows the magnitude of change throughout the City since 2008. In most cases, those areas with the highest amount of relative loss (negative values) were not large clearings of forested areas, but rather the widespread removal of individual trees and small patches in areas which had below-average tree canopy to begin with.
Philadelphia Tree Canopy Assessment
The relative tree canopy change percentage shows the magnitude of change throughout the City since 2008. In most cases, those areas with the highest amount of relative loss (negative values) were not large clearings of forested areas, but rather the widespread removal of individual trees and small patches in areas which had below-average tree canopy to begin with.

However, Smith-Fichman said the city has planted thousands of trees over recent years that might not be showing up yet in aerial imagery, as the data only reflect trees over eight feet in height.

Canopy cover is more prevalent in the northern and western parts of the city, where there are more parks. But the most densely urbanized and industrialized areas, including Center City and neighborhoods along the Delaware River, “have strikingly low amounts of tree canopy and therefore experience the negative impacts, such as increased heat,” the report states.

Though the report acknowledges it will be difficult to plant trees in heavily industrial or commercial zones, it suggests the city can increase coverage by planting trees along roads.

“The launch of the Future of the Urban Forest planning process is an opportunity to accelerate efforts from across Philadelphia to protect our tree canopy and improve quality of life and health outcomes for residents,” Mayor Jim Kenney said in a statement.

Kathryn Ott Lovell, parks and recreation commissioner, said the city wants to create "more opportunities to plant new trees in parts of the city historically lacking the benefits of trees.”

In 2009, the city’s Greenworks initiative set a goal of a 30% tree canopy in every Philadelphia neighborhood.

Multiple city departments provided money and built partnerships with community organizations and corporate donors including TD Bank through the TreePhilly program, which has given away 24,000 trees since 2012.

The Pennsylvania Horticultural Society has also contributed through its TreeTenders program, which offers training in planting and caring for trees.

Smith-Fichman said Thursday’s meeting with partners and stakeholders will be the largest gathering ever in the city to discuss trees. More public meetings will gather input from residents to help craft the plan.

She said they will use data from the report as a starting point for the plan, funded mostly by the William Penn Foundation with additional money from TD Bank.

“The report doesn’t tell us why, it just tells us that we lost canopy,” Smith-Fichman said. Trees could be dying from old age, or heat or insects. Construction could be an issue, as could storms. Some species could be more vulnerable to city stresses.

“You can’t expect to have the same canopy goal for a residential area, or commercial or industrial area, that you would have in a woodland park,” Smith-Fichman said.

Changing attitudes will be a focus, too. In the past, residents have complained about trees, saying they can be a nuisance and safety issue on small plots of land or at curbside.

“Those are all valid concerns,” Smith-Fichman said. “But trees are living things, and you can’t always control them.”