As Philadelphia plants thousands of trees to help cool heat-stricken sections of the city, residents can use a new online tool to see how the decade-long project might help their neighborhoods.
You can slide between two overlapping maps of the city: one that reveals how bad the summer heat problem is on a detailed, block-by-block basis, and another that shows which areas are prioritized for tree-planting.
There’s also a standalone map with detailed info showing how temperature islands shift throughout the day. The western part of Washington Avenue in Point Breeze, for example, is one of the city’s hottest places in the city in mornings and evenings, but other areas get hotter midday.
The maps are part of a new website developed by the Nature Conservancy’s Pennsylvania staff, which describes how citizen-scientists collected heat readings around the city last summer and what they found.
The new slider and other information are meant to help residents understand and shape progress on the Philly Tree Plan, said Richard Johnson, the Nature Conservancy’s urban climate resilience manager.
The site also serves as a “call to action” for officials who are overseeing planning and planting efforts, he said.
“Policymakers can use this now to more easily look at how it can inform decisions they’re making around cooling efforts in the city, and use it as an advocacy tool to drive investment where it’s needed the most,” said Johnson, who previously worked on the heat mapping effort at the Academy of Natural Sciences.
There’s a major disparity in tree cover between neighborhoods with lower median incomes and those with wealthier residents, a 2019 analysis by WHYY’s PlanPhilly found. The poorest half of city residents lived in areas with just one third of all street trees.
And more trees in an area directly correlates with fewer shootings, according to a 2022 University of Pennsylvania study, which found that neighborhoods that are highly tree-deprived stand to see the greatest decrease in violence when they’re greened.
Using tree-planting and other methods to combat the effect of high temperatures has become a priority for the city as climate change heats up neighborhoods in the summer. It’s especially important for areas with fewer trees, lots of pavement and dark roofs, and with residents who are more vulnerable due to poverty, poor health, and other factors.
“We could experience as many as three additional weeks of days over 95 degrees by the 2030s because of climate change. So the time to prepare for those heat waves is now,” Johnson said.
Last summer, volunteers drove around Philadelphia with thermometers attached to their cars to create the Nature Conservancy’s new higher-resolution heat map. Philly was one of 14 cities and counties chosen by the National Oceanic and Atmospheric Administration to participate in the agency’s urban heat island mapping project.
The study showed a temperature differential between areas of the city of about 10 degrees, with the hottest areas largely in Center City and South Philly. An earlier study using data from 2013 to 2015 showed wider differences between Philly neighborhoods, some as wide as 22 degrees.
In September the U.S. Department of Agriculture announced a $12 million grant for the Philly Tree Plan, which the city described as the largest investment in Philadelphia’s urban forest in almost 30 years.
The plan was released in February after a lengthy community-engagement process involving more than 9,000 residents. It found that getting every neighborhood to 30% tree cover within 30 years would cost an average of $25.5 million per year, or about $765 million in total.
