• Our Shared Waters

How Philadelphians are innovating with Trees to fight climate change, improve water quality & mental

BY JASON PETERS | April 05, 2021


This article was originally published in Green Philly.


Trees are underrated, underappreciated, and making a comeback throughout Philadelphia. With benefits like alleviating the impact of the Heat-Island Effect and improving water quality, expanded tree growth is a remedy to many societal woes in both urban and rural settings.


For decades, the destruction of trees was synonymous with economic development. Now, the script has flipped and trees are raising property values in both rural and urban areas.

Across the Philadelphia region, there are a variety of tree-related programs attempting to make life greener and provide arborous benefits that the city has always lacked.

Tree-Canopy

An Urban Tree Canopy is the layer of tree leaves, branches, and stems that provide tree coverage of the ground when viewed from above. A 2019 tree canopy assessment of Philadelphia by the University of Vermont found that Philadelphia lost 6% of it’s natural tree canopy from 2008 to 2018, totaling a loss of 1095 acres of tree cover.

Pictured: Jasmine Thompson of Philly Forests

This 2019 study of Philly tree canopy uncovered that the “areas with the highest amount of relative loss 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.” When assessed by zip code, it’s apparent that North Philly was the most widely de-treed area in the city, while South Philly experienced mild gains in tree canopy area.

Heat-Island Effect & Equity

In Philly, richer zip codes have more trees. More trees correlate to cooler temperatures, whereas less trees in a major city creates a Heat Island Effect, which occurs when city structures like buildings and roads absorb and re-emit the sun’s heat, raising the temperature. The EPA says that “areas where structures are highly concentrated and greenery is limited, become ‘islands’ of higher temperatures relative to outlying areas.” In spaces facing the Heat Island Effect temperatures are 1–7°F higher during the day and about 2-5°F higher at night.

The benefits of tree cover go far beyond temperature. Tree cover reduces the cost of air conditioning and heat in a neighborhood, as well as increases property values. Canopies lower air temperatures, reduce air pollution, and provide animals with a place to live.

With Philly Forests, Jasmine is hoping to bring equity to Philadelphia, through trees. “The amount of trees in a neighborhood is directly correlated to the amount of wealth and that’s not cool,” Thompson says “so we want to close that gap, and clear that disparity.”

Philly Forests has a mission to plant 2,500 trees by 2026 in low tree canopy areas.

Similarly, the Department of Conservation and Natural Resources has created the “Keystone Tree Fund” which will be funded by a new “voluntary $3.00 check-off box” offered through PennDOT. When Pennsylvanian’s go to renew their driver’s license or vehicle registration online, there will be an option to donate towards planting and maintaining more trees across the commonwealth.

According to Teddi Stark of the DCNR the Keystone Tree Funds will be split “40% of the money goes to urban trees, 60% goes to streamside trees.”

Forest Buffers

Forest buffers are the trees, shrubs, and grasses planted along streams that help to maintain the health of waterways. 60% of the Keystone Tree Fund is going towards developing riparian forest buffers along Pennsylvania’s 86,000 miles of rivers and streams. “Trees beside streams help slow pollution, any pollution that would run off from the rain is really mitigated by trees and kept out of the water,” explains Stark.

The DCNR,’s stated goal is to plant “95,000 acres of riparian forest buffers statewide by 2025” with the goal of improving Pennsylvania’s waterways. The US Department of Agriculture highlights the following benefits of forest buffers “filtering nutrients, pesticides, and animal waste from agricultural land runoff; stabilizing eroding banks; filtering sediment from runoff; providing shade, shelter, and food for fish, and providing wildlife habitat.”

Water Quality

Trees are helpful for water management in city settings as well as forest settings. “When rain falls in urban settings it typically flows into a storm drain,” Stark explains, “planting trees in urban areas helps slow that rain down, which helps to reduce flooding and stormwater problems.”

An 2015 EPA study explains that when stormwater flows over city streets and sidewalks, it collects debris, chemicals, sediment, and other pollutants that can seriously impair water quality. Urban trees “help slow down and temporarily store runoff and reduce pollutants by taking up nutrients and other pollutants from soils and water through their roots.”

Trees benefit water supplies in a cavalcade of ways. Their obstruction provides relief to storm drain management, through transpiration trees absorb water from soil, and through phytoremediation trees take up trace amounts of harmful chemicals and solvents from the soil.

Trees can Boost your Mental Health

Jack Braunstein, the TreePhilly Program Manager, talked to Green Philly about the “calming and pacifying effect of being around greenery and life.” Braunstein reiterated the mental health benefits of city trees and greenery, exclaiming “this is basically an essential public health service, if you live on a tree-lined street your mental health will likely be better than a street with no trees.” Multiple studies have shown links between trees and mental health.

A 2018 Australian study from the University of Wollongong found that “the residents of neighbourhoods with a higher amount of tree canopy had better mental and general health.”

Property Values

To pair with the mental health benefits is an added financial benefit. Braunstein explains “developers may not want trees because it’s another square foot they can’t rent out or don’t want to rake leaves, but studies show that one tree can improve your home’s value by 9%.” Homeowners can use the National Tree Benefit Calculator to discover the overall economic value of trees on your property.

Philly Trees Going Forward

TreePhilly is a private-public partnership program of the City’s Parks & Rec Department, Fairmount Park Conservancy, and funded by TD Bank. TreePhilly is giving away street trees and yard trees for Philadelphia residents to plant on their property. Their stated goal is to “reach 30% tree canopy coverage in every Philadelphia neighborhood.”

The “Philly Tree Plan” is TreePhilly’s next step forward in urban tree planning explains Braunstein “We’re actually in the process of a comprehensive 10 year strategic plan and city wide survey about what their thoughts on trees are.” There are a number of hurdles in planting trees on private and public property in major cities, the Tree Plan seeks to address those issues.

Private citizens like Jasmine Thompson, governmental agencies like the DCNR and PennDot, and public-private partnerships like TreePhilly all recognize the benefits of planting trees in a community. When Pennsylvania was just a mere British-Colony it was known as Penn’s Woods, nearly a quarter through the 21st century we’re working to bring Penn’s Woods back.

Broke in Philly is a collaborative reporting project on solutions to poverty and the city’s push toward economic justice. Green Philly is one of more than 20 news organizations in the collective. Follow us on Twitter @BrokeInPhilly.

Cover Photo by Jason Peters