Nine U.S. Cities That Love Their Trees – and What They’re Doing About It…
More and more American cities are working to conserve and preserve their trees. The impulse is mostly functional: Trees provide shade, purify the air, and decrease runoff. To celebrate Arbor Day, take a look at this list of cities that love their trees and are working to conserve their tree canopies.
New York | 21% tree cover
New York City is most of the way through an eight-year tree-planting blitz that will see one million new trees in the ground by 2015. The MillionTreesNYC campaign, a public-private partnership, has planted about 834,000 so far. The program works with regional nurseries to plant more than 150 different species. It will be years before the city can really gauge its canopy-expansion effort; first the trees have to grow big enough for satellites to see them.
Philadelphia | 20% tree cover
Philadelphia’s Fairmont Park is the largest city-owned park in the world. It dates to the 1860s, when the Fairmont Park Commission acquired land along the Schuylkill River to keep big industry out. Continuing the tradition today, Philadelphia’s Green City, Clean Waters program seeks to protect the city’s watersheds with trees, which also help to intercept, filter, and store stormwater, lightening the load for the city’s drains and pipes.
Austin | 37% tree cover
Last March, Austin adopted an Urban Forest Plan to help sustainably preserve its trees through a drought—which began in 2010—and in the face of expected climate change. Almost all the water in Austin’s tree-watering tanker trucks is reclaimed and filtered municipal wastewater, reducing the amount of potable water used for tree initiatives by one million gallons per year.
Detroit | 23% tree cover
By 1989, Detroit was losing four trees for every one planted, a byproduct of urbanization and the insect-borne Dutch elm disease. Another nefarious insect, the emerald ash borer, arrived in 2002. But things are looking up: The Greening of Detroit has planted 82,000 trees in the past 15 years, and the group is working with the U.S. Department of Agriculture to test the healing potential of trees planted in polluted brownfields.
Washington, D.C. | 36% tree cover
Urban tree initiatives in the nation’s capital date to George Washington’s presidency, when Pierre L’Enfant—a Frenchman accustomed to Europe’s plentiful urban green spaces—emphasized trees and parks in designing the city. Today, Washington has more green space per capita than any other similarly sized U.S. city—largely a legacy of government support. The District spends more money on its trees than any other city: $10 million per year.
Baltimore | 27% tree cover
Canopy assessments have helped Baltimore’s foresters identify the neighborhoods most in need of green, with some surprising benefits. A recent study in the journal Landscape and Urban Planning reported that a 10 percent increase in the city’s tree cover corresponded with an estimated 12 percent decrease in crime over four years. The theory is that green urban space invites pedestrian traffic and fosters community pride, which means more eyes on the street.
Portland | 30% tree cover
The tree canopy in Portland, Oregon, is part of the city’s effort to build what it calls “green infrastructure.” The average tree intercepts more than 500 gallons of stormwater each year: Besides being absorbed by the trees’ roots, water is caught by the canopy and evaporates before it hits the ground. The canopy’s interception of stormwater reduces the amount that flows through Portland’s municipal drains and pipes by more than one billion gallons annually.
Tampa | 32% tree cover
In Tampa, you’re most likely to appreciate the urban forest on a hot day. Trees and other plants lower temperatures by providing shade and through a process called evapotranspiration, in which trees draw water from soil and release vapor through leaves. According to the Environmental Protection Agency, urban green spaces can lower temperatures by 2 to 9 degrees Fahrenheit (1 to 5 degrees Celsius) and shaded surfaces can be a dramatically cooler.
Pittsburgh | 42% tree cover
A significant portion of hillside around the world’s former steel capital has variously been mined, logged, and built upon. But with the passage of time, much of it has been naturally reforested. This new-growth forest and the city’s four large parks make for a patchy canopy, so local environmental organizations have enlisted volunteers to plant 20,000 trees in recent years. The expanded urban forest removes 532 tons of air pollution every year.