Urban Forestry Is Having its Moment

Trees and forests in urban spaces play an essential role in mitigating the impacts of climate change, including cooling temperatures in inner cities, sequestering carbon, and providing equitable access to green space for city residents. This year’s Hixon Conference focused on how urban forests can help mitigate the impacts of a changing climate. The conference, which drew more than 1,000 registrants, was hosted by the Hixon Center for Urban Ecology, the USDA Forest Service, Connecticut Department of Energy and Environmental Protection, and the Natural Areas Conservancy and held at Kroon Hall on September 22, 2023.

"Everyone has a story that has a connection to a tree,” said keynote speaker Beattra Wilson, assistant director for cooperative forestry at the U.S. Forest Service.

Here are five key takeaways from the conference:

Urban forestry is having its moment.

Right before her keynote talk, Beattra Wilson learned that more than $1 billion had been awarded to fund 385 grant proposals aimed at combating extreme heat and climate change and increasing equitable access to trees and nature by planting more trees. The grants were made possible by the Inflation Reduction Act and represent the largest single Department of Agriculture investment to date in urban and community forests.

The investment in the Forest Service’s Urban and Community Forest Program is part of President Biden’s Justice40 Initiative, which works to ensure the benefits of certain federal investments reach communities that are marginalized, underserved, and overburdened by pollution and underinvestment.

“We were hidden figures for a very long time. This is our season. We are currently the cool kids,” Wilson said. “These communities have long been waiting for this kind of relief.”

Local decisionmakers can have a powerful impact.

Yvonne Aki-Sawyerr, mayor of Freetown, Sierra Leone, had a goal when she ran for office that many dismissed as unrealistic. She had witnessed the impacts of climate change — from mudslides in mountain areas to flooding in coastal regions to severe heat in the city — and was determined to take steps to mitigate future impacts by transforming Freetown to “Treetown.”

That meant increasing tree cover by 50% in the city, which, when she did the math, was about 750,000 trees. To raise the revenue needed to meet that goal, Aki-Sawyerr threw a local fundraiser and tapped funding provided by the World Bank. Her administration not only purchased trees, but also hired more than 1,500 Freetown youth to work in community-based forests. Aki-Sawyerr has now exceeded her original goal, with 850,000 newly planted trees and is now aiming to plant 5 million more trees by 2030.

“Transformative leadership is difficult. Scientists know what has to be done, but how does it get done?” she said during a panel discussion on local decisionmakers.

The panel featured Matúš Vallo, mayor of Bratislava, Slovakia; Ioannis Anastasakis, vice mayor of technical projects in Heraklion, Crete, Greece; and Justin Elicker ’10 MEM/MBA, mayor of New Haven.

It takes a village to maintain urban forests.

There are about 1.8 million acres of forests embedded in urban landscapes, and they are often comprised of complex tree species. If local leaders are only focusing on planting trees and not caring for natural urban forests, then they are quite literally missing the forests for the trees. That was the message from ecologists participating in the “Protecting Threatened Natural Forests in Cities” panel moderated by Mark Bradford, professor of soil systems and ecology at YSE.

Urban forests face many challenges from development, climate change, disturbances, invasive species, and disease. It is important, panelists said, to think of every resident as a potential steward of urban forests and to engage citizen scientists in research and observation. It is also vital for government leaders to communicate about the work they are doing to preserve urban forests in neighborhoods, including thinning, prescribed burns, and tree removal.

“We need the public to realize we need to maintain forests,” said Amy Witt, a park ecologist with Forest Park Forever.

Increasing shade cover is a scalable solution to hotter cities.

Since the start of 2023, Phoenix, Arizona, has clocked more than 50 days at 110 degrees or more. To address the challenge of a hotter city, officials in Phoenix are rethinking how infrastructure can be utilized to provide more shade.

Ariane Middel, an associate professor the Urban Climate Research Center at Arizona State University, has been creating shade maps using MaRTy, a human biometeorological chart, to measure mean radiant temperature and shade performance. The maps are used to inform the city’s Cool Corridor Program on where to increase shade infrastructure.

Phoenix, and neighboring Tempe, have ambitious goals to increase shade using tree canopy. Phoenix, which was awarded more than $1.4 million to assist with planting up to 200 trees per mile as part of the Cool Corridor Program, has a goal of increasing canopy coverage to 25% by 2023. It has about 12% canopy coverage right now. Tempe, which has about 11% coverage, aims to increase it to 25% by 2040.

Living schoolyards keep students cool and facilitate place-based learning.

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Across the U.S., nearly 50 million K-12 students attend school every day on thousands of square miles of public land, but many of those schoolyards lack trees and other green spaces.

“We need to help schools systemically shift their grounds from pavement into a more nature rich environment,” said Sharon Danks, founder and CEO of Green Schoolyards America. “Millions of kids across the country don’t have any shading.”

Living schoolyards that include large clusters of shade trees planted in places that students regularly access during the school day, can be a solution, Danks said.

“We’re trying to create living school grounds that are richly layered park-like environments that strengthen local ecological systems and climate resilience while also providing place-based learning resources and vibrant social spaces for children of all ages,” she said.

In California, Green Schoolyards and other partners are working on a pilot program to increase trees on school grounds, a program that, if successful, could be replicated elsewhere.