Since the 1970s, there has been a 25 percent decline in tree canopy cover. This is a dramatic trend that is costing cities billions of dollars. Now, a number of major cities- including Washington, Baltimore, Minneapolis, Chicago, Denver, and Los Angeles- have launched sizable tree-planting programs. Moreover, in the face of record summer heats, planting trees could be the answer to global warming. These articles from the Washington Post and Sacramento Bee describe how trees sequester carbon dioxide, reduce the power needed to cool homes and offices in the summer (less electricity means fewer greenhouse gasses spewing from power plants). The planting of 50 million new trees in strategic locations could save about 12,5000 gigawatt hours of electricity in California each year. That is equivalent to the juice generated by seven new large power plants or what is consumed by 683,000 homes each year.
In September 2006, United Airlines published an article lauding the many benefits of city trees in their in-flight Hemispheres Magazine. Trees along the street, in residential yards and in parks, lower energy consumption through shade, reduce the need for (and cost of) stormwater management facilities, improve human mental and physical health, contribute to economic sustainability, and clean pollutants from the air. One study recommends a minimum of 40 percent tree cover for most urban areas.
Save the Shade (PDF)
Trees are essential to the health and livability of our nation’s cities and towns. Cleaner air, greener streets, and healthier neighborhoods are crucial to the prosperity of the American economy. But lasting progress won’t come without changes in domestic policy. In response, the Alliance for Community Trees organized the first annual Green Infrastructure Summit and Urban Trees Forum. The two days of Hill meetings and discussions included the following expert witnesses:
Using Green Infrastructure to Enhance Highways (MP3)
Anne Canby, President, Surface Transportation Policy Partnership
Greening as a Catalyst for Neighborhood Stabilization (MP3)
Kevin Gillen, University of Pennsylvania Wharton School of Business
Neighborhood Parks and Public Health (MP3)
Deborah Cohen, Senior Natural Scientist, RAND Corporation
Energy Conservation through Trees (MP3)
Zack Hill, Sr. Manager of Federal Government Affairs, Alliant Energy
In 2000, the USDA Forest Service’s Office of Communications developed a campaign to inspire urban people to become involved in planting trees. About $380,000 was invested. Products included: market research, test messaging, a five-year communications plan, downloadable advertisements and PSAs, logos, and some selected media buys.
The University of Illinois has produced a great deal of research about the social benefits of trees. In particular, see research summaries on the left hand side navigation: “Canopy and Crime,” “Neighbors & Nature,” “Plants & Poverty,” etc. Their work has really focused in on the question of how trees and greenspace can help support healthier social behaviors in at-risk communities. Several of the studies compared public housing developments in Chicago – finding that green spaces, trees, etc. help lower crime because they encourage more social interaction, increased social networks, and simply more eyes on the street.
The Centers for Disease Control (CDC) has an Environmental Health program. There are several links here where CDC notes the role of greenspace to Social Capital, Mental Health, and Children’s Health & the Built Environment.
The University of Washington has research about how trees impact the economic health of retail districts, particularly those old main street areas that are often under-performing. Consumers are willing to spend more when the physical environment is attractive – trees, benches, flowers etc. This suggests that beautification and trees are a cost-effective tool for revitalizing abandoned and under-invested commercial districts in cities.
This general publication includes research facts about the role of trees in cities.
Images care of the Urban Forest Project’s initiative Design Times Square. The Urban Forest Project brings 185 banners created by the world’s most celebrated designers, artists, photographers and illustrators to New York’s Times Square. Each banner uses the form of the tree, or a metaphor for the tree, to make a powerful visual statement. Following their display, (September 1- October 31, 2006) the banners will be recycled into tote bags and sold at auction, with proceeds going to scholarship and mentoring programs that benefit students of the visual arts. For more information, visit: http://www.urbanforestproject.org