Trees Offer Significant Benefits as Charlotte Area Officials Expect Future Growth

American Forests
Wednesday, 19 March 2003

New study shows financial and environmental benefits of urban trees

According to a new study by conservation organization AMERICAN FORESTS, Mecklenburg County, North Carolina's urban forest has declined significantly over the last 17 years, including drastic changes in the City of Charlotte and surrounding towns. The analysis shows a 22 percent tree canopy loss between 1984 and 2001 over the entire county—showing the biggest losses in Pineville and Cornelius. These losses indicate patterns of decline in air and water quality—a condition that AMERICAN FORESTS officials say, can be changed with better management and increased tree cover. AMERICAN FORESTS' CITYgreen® computer software was used to analyze the environmental benefits of trees.

Mecklenburg County, which surrounds the Charlotte Metropolitan Area, has seen a 72 percent growth in population since 1980, making it one of the ten fastest growing metro areas in the nation. To calculate the environmental impacts of the population increase, the Charlotte Tree Advisory Commission engaged AMERICAN FORESTS to conduct an Urban Ecosystem Analysis (UEA) of 351,000 acres of Mecklenburg County, including the City of Charlotte and its rapidly developing suburbs.

"This analysis points out that we need a regional tree canopy policy that deals with sprawl and works across political boundaries," says Charlotte Mayor, Patrick McCrory. "The policy should set specific and measurable goals for canopy. Trees are our signature in the Charlotte region and we should be a role model for the nation."

The Urban Ecosystem Analysis technique conducted in Mecklenburg County used satellite and aerial imagery, Geographic Information System technology, and scientific research to calculate the benefits trees provide to the urban environment. The analysis also serves as an introduction for local leaders to learn about ways to use tree cover as an asset—building a "green" infrastructure for future city management decisions.

According to the report, Mecklenburg County currently has 53 percent tree cover, and based on American Forests' recommendation of 40-55 percent, Charlotte is within a healthy range. However, with the population expected to climb over the next 15 years, the associated tree loss will result in costly and unhealthy environmental consequences. To this end, the report makes a number of recommendations for the area's decision-makers, including the Charlotte Tree Advisory Commission. The study suggests that the city develop public policies that increase tree cover and promote green infrastructure. Second, the community should include trees and the values associated with trees when making land-use decisions. Lastly, the analysis recommends that the community should set tree cover goals and institutionalize a system to maintain these goals. "The study shows that Mecklenburg's trees are a very important community asset," said Gary Moll, Vice President of AMERICAN FORESTS' Urban Forest Center. "The

real strength of this project is in the data it provides to regional and local communities who can use it for future planning and local analyses of tree canopy. The Mecklenburg communities have now taken the first step and are poised to take full advantage of the project."

The Charlotte Tree Advisory Commission has arranged for AMERICAN FORESTS to train local planners, environmental departments, forestry professionals, parks and recreation, local GIS experts, the UNCC Urban Institute, the Catawba Land Conservancy, and others to use CITYgreen software and the data from the analysis. These local professionals can then effectively manage and plan for a healthy urban tree canopy. The Tree Commission is also working with local universities, environmental departments, park and recreation, and environmental groups on more targeted canopy analyses and local initiatives to plant and conserve trees for maximum environmental impact. "The region is experiencing a major development boom," explained Rick Roti, Chairman of the Charlotte Tree Advisory Commission. "As our leaders and planners work to manage growth and protect our environment, this information and the CITYgreen software tool can be integrated into the planning process, and can also be shared with the entire region as we plan for open space protection and the future."

AMERICAN FORESTS'S study also highlights the important role trees play in retaining stormwater in urban areas. Trees help reduce stormwater runoff by intercepting rainwater on their leaves, branches and trunks, where it evaporates, or slowly soaks into the ground, reducing peak flow after a storm. Trees also reduce the volume of runoff. Municipalities must spend millions of dollars for flood control systems and sewer infrastructure to handle stormwater runoff. Without trees in the Charlotte Metropolitan Area, the cost of building water storage units would be very expensive—$1.87 billion dollars, in fact.

Besides reducing stormwater runoff, Mecklenburg County's tree canopy provides other benefits including the removal of 17.5 million pounds of air pollutants each year—a value estimated at $43.8 million annually. The area's urban forest currently stores an estimated 7,957,791 tons of carbon and sequesters nearly 61,954 tons of carbon each year. These benefits become more important with the realization that significant tree canopy has been lost over the last 17 years. The analysis compared classified Landsat TM satellite images between 1984 and 2001. While the study revealed a 22 percent loss in tree canopy cover over this time period the area still retains a 53 percent canopy cover.

AMERICAN FORESTS is a national leader in the urban forestry movement. The organization combines education, action, and research into programs that improve the trees, forests, and overall environmental health of our communities. In addition to conducting Urban Ecosystem Analyses in regions around the US, AMERICAN FORESTS developed CITYgreen software for communities to use in calculating the value of urban forests in their local areas. Every two years, AMERICAN FORESTS organizes the National Urban Forest Conference, which brings together practitioners, researchers, citizen groups, legislators, and others interested in improving the urban environment. The 2003 National Urban Forest Conference, Engineering Green, will be held in San Antonio, Texas, September 17-20.

Images from the study are available on an online server. Please call Rachel Brittin at (202) 955-4500 x234 for the address. For a copy of the Mecklenburg Urban Ecosystem Analysis Report visit American Forests online at www.americanforests.org/resources/rea/.

For more information, or to contact American Forests, see their website at: www.americanforests.org