Philadelphia has hired a landscape architectural firm to design an urban forest plan that would both beautify and reduce heat in some of the more shade-challenged areas of the city. With most of these in the poorer, more vulnerable neighborhoods, the plan aims to improve health conditions in places that need it most.

Hinge Collective, a public-interest design firm in Philadelphia, and its subcontractors will be paid for their work through $217,750 in grants primarily from the William Penn Foundation, but also from TD Bank and the Pennsylvania Department of Conservation and Natural Resources.

The city announced its intention last year to launch a 10-year Urban Forestry Plan. It came on the heels of a report that showed Philadelphia had lost the equivalent of 1,000 football fields worth of leafy shade over the last decade, despite efforts to increase it.

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 in December 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.

Tree canopy refers to the part of an area shaded by the upper portion, or crown, of trees.

Hinge Collective’s job will be to figure out how to reverse that — not an easy task when so much of the city landscape is made up of small sidewalks, vast industrial and commercial areas, and tightly packed houses. Residents have said they fear lawsuits over trees that uproot narrow sidewalks, or branches that could break off in storms.

“It is no small task what the city is looking to do, although I think there already exists in the city an appreciation for the trees that we do have,” said Alexa Bosse, a landscape architect and principal in Hinge Collective.

Bosse said the plan will take from 12 to 18 months to complete.

Hinge Collective won the contract through a competitive bid process and plans to use a range of mostly Philadelphia-area subcontractors.

For example, Azavea will handle mapping. The nonprofit Rising Sons will help with community engagement. The Lindy Institute for Urban Innovation and Glen Environmental will assist in public policy. And White will help develop an ambassador program. Other team members include Little Giant Creative, SavATree, and Sahar Coston-Hardy Photography.

Including people from various neighborhoods is vital, Bosse said.

“We’re looking for a way to find what people like about trees and what the barriers are,” Bosse said in reference to the tree canopy decline. “Our goal is to meet with as many people in different capacities as possible and find out what’s keeping them from having trees or wanting them."

Kathryn Ott Lovell, Philadelphia’s commissioner of parks and recreation, said Hinge Collective was chosen "because of their proposal’s focused and robust approach to community engagement.”

"Their input will help us find the best ways to work with them to plant new trees and bring resources to parts of the city that lack a substantial tree canopy,” Ott Lovell said.

The relative tree canopy change percentage shows the magnitude of change throughout the City since 2008 (Figure 4). 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 (Figure 4). 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.

The Urban Forestry Plan is an outgrowth of the city’s Greenworks program launched in 2009 with the goal of achieving 30% tree canopy in every Philadelphia neighborhood. TreePhilly, the tree giveaway program, is part of that effort.

But to see how its effort was working, the city commissioned the University of Vermont Spatial Analysis Lab, which used aerial imagery and light detection and ranging (LIDAR) data to map out the extent of the city’s tree canopy. The lab found tree canopy now covers only about 20% of land within the city. However, the city has planted thousands of trees in recent years that might not show up yet in aerial imagery.

The report found canopy cover is more prevalent in the northern and western parts of the city, where there are more parks. The most densely urbanized and industrialized areas, including Center City and neighborhoods along the Delaware River, have strikingly low amounts of canopy, which leads to more heat — sometimes 10 to 20 degrees hotter than in shaded areas.