Forests & Cities: Urban Forests
- Because of their proximity to human activity, urban forests are exposed to more man-made disturbances than their rural counterparts, which can negatively affect their health, growth and ability to perform ecosystem services.
- Many non-native invasive species and diseases are introduced in urban areas, threatening the urban forest and potentially spreading to rural forests.
- Urban areas are subject to much higher rates of pollution than rural areas, threatening the health of both people and urban forests.
- As urban areas continue to expand, forests become fragmented and destroyed, decimating forest health and biodiversity.
- Urban areas have lost more than 600 million trees to development over the last 30 years, and urban areas are expected to increase substantially over the next 50 years.
Why We Care
American Forests defines urban forests as “ecosystems composed of trees and other vegetation that provide cities and municipalities with environmental, economic and social benefits. They include street and yard trees, vegetation within parks and along public right of ways, water systems, fish and wildlife.” Thus, urban forests are not only just about the trees in the city, but rather they are a critical part of the green infrastructure that makes up the city ecosystem.
All trees provide certain benefits to their ecosystems. In an urban forest, many of those benefits are directly related to the people who live around them. Since more than 80 percent of Americans live in urban areas, it is important to understand the many ecosystems services that our urban forests provide.
Urban forest help purify the air we breathe. Just 100 trees can remove two tons of carbon dioxide from the air annually. Urban trees in the lower U.S. have been found to remove nearly 800,000 tons of air pollution from the atmosphere every year. In the modern day of bustling factories and countless cars on the road, this service of air purification has become more necessary than ever.
Urban forests help manage a city’s water. Because a city has so many impermeable surfaces, rainwater often builds up rather than being absorbed into the ground. This means that even a small rainstorm can cause flooding, as most of the water overflows into the stormwater system rather than into the ground. As the rainwater flows over the pavement, it becomes contaminated with pollutants and may eventually end up in our urban streams and waterways — and even our faucets. Urban forests help in several ways: They intercept rainfall, allowing the water to be absorbed into the tree, roots and soil. This often results in cities not having to build as many artificial stormwater controls, saving the city and its citizens money. Urban forests purify the water on its way into the ground by removing the pollutants collected. The water retained by the urban forest also helps to sustain the growth of the urban trees, parks and vegetation. These services, provided naturally instead of artificially, can save a city billions of dollars each year. In fact, a single front-yard tree can intercept 760 gallons of rainwater in its crown, reducing runoff and flooding on your property.
Urban forests also help reduce energy demand. When planted in the right place, urban forests provide shade to homes, businesses, roads and parking lots. Anyone who has parked under a tree on a hot day can appreciate the cooling effects of foliage, but did you know that it could also improve your health and save you money? In parking lots, trees help keep the cars cool — 40-50 degrees cooler, in fact— and cooler cars produce less pollution. Shade around your home can do the same thing. Just three large trees around your home, two on the west side and one on the east, can provide enough shade to reduce your air-conditioning costs by 30 percent in the summer. And, when placed properly to reduce wind exposure, they can reduce heating bills in the winter by two to eight percent. In fact, 100 million mature trees growing around homes in the U.S. can save a collective $2 billion every year in energy costs.
These are only a few of the many benefits that urban forests can provide if kept healthy and cared for properly. They also provide bird and wildlife habitat and recreational opportunities, improve soil quality, reduce stress and crime rates, create a natural buffer to reduce the everyday noise of the city, add to your home’s property value and more.
Over the years, American Forests has led efforts in developing the field and practice of urban forestry, advancing knowledge of the values of urban forests and increasing awareness with key audiences. Our organization was created while the U.S. and its urban centers were still developing. Since then, we have worked to educate people on the benefits that trees can provide to cities and the role that they should play in urban planning.
American Forests is currently working on a project for “Building Public Awareness of the Values of Sustainable Urban Forests” with support from the USDA Forest Service. Over this next year, we will be working on several activities to advance the understanding and use of science-based measures of the ecosystem services of urban forests, as well as activities to heighten public awareness of the contributions of urban forests toward sustainable urban ecosystems and quality of life. Stay tuned for our exciting work on this project — your city may just be one of the one’s featured!
American Forests is also the chair of the policy work group and member of the steering committee for the Sustainable Urban Forest Coalition (SUFC), a group of nonprofits, businesses and foresters that advocate for legislation relating to urban forests and green infrastructure. As a member of SUFC, we highly support the Vibrant Cities & Urban Forests: A National Call to Action, which offers 12 recommendations to help improve the way we live in, manage, study and rebuild our cities and towns over the next few decades.
American Forests also supports the Partnership for Sustainable Communities. This collaboration between the Environmental Protection Agency, the U.S. Department of Transportation and the U.S. Department of Housing and Urban Development works to improve the infrastructure that cities need while also protecting the environment. We advocate for green infrastructure to play a larger role in urban communities across the country. Because American Forests understands the relationship between water and forests, particularly in urban centers, we also advocate for better regulations and policies relating to urban forests as water-management systems.
American Forests also plants trees in urban centers. Many metropolitan areas across the U.S. have insufficient tree canopies. Through our Global ReLeaf program, we work with local groups to find the best places to plant trees to enhance the urban forest.
- Learn more about why we care about urban forests
- View our urban tree plantings here
- Learn more about our urban forests policy work here
- Read our blog posts about urban forests
What You Can Do
- You can advocate for eco-friendly legislation. Write to your mayor, governor, state representatives and congresspeople to support legislations and policies that can protect urban forests and trees in your community. Click here for a toolkit (coming soon).
- Find a tree-planting organization in your area and volunteer to plant or care for trees in your community. Visit the Alliance for Community Trees to find a group in your town.
- Sign up for action alerts about urban-forestry issues — we’ll keep you posted on opportunities to get involved.
- Follow our blog, Loose Leaf. Check out our monthly, urban-forest blog post every third Tuesday of the month.
- Contribute to American Forests to help us continue our policy work and plant more trees in urban forests
 Urban Forest Research, Center for Urban Forest Research, March 2001.