RELATIONSHIP AMONG TREE CANOPY QUANTITY, COMMUNITY DEMOGRAPHICS, AND TREE CITY USA PROGRAM PARTICIPATION IN MARYLAND, U.S.

Journal of Arboriculture, Nov 2004 by Galvin, Michael F, Bleil, David

Abstract. The Tree City USA (TCUSA) program is a national program in the United States that provides recognition to communities that meet certain standards, including having a tree ordinance and spending at least US$2.00 per capita on urban forestry. Census data for 2000 were combined with records on TCUSA program participation and tree canopy cover data for 74 communities in Maryland, U.S., to ascertain relationships among tree canopy quantity, community demographics, and Tree City USA program participation. Communities participating in TCUSA had widely varying demographics (2.2% to more than 97% nonwhite) but tended to have larger overall populations and larger nonwhite populations than did nonparticipating communities, with the percentage of nonwhite population slightly higher for nonparticipants. Multivariate statistical analysis showed that the most predictive variable related to the amount of canopy cover is the size of the city in hectares (acres). A combination of city population, hectares (acres) of tree cover, expenditures per capita on trees, and city size in hectares (acres) produced the greatest predictability in whether a city participates in the TCUSA program. The relationship between quantity of tree canopy and total population was stronger in participating than in nonparticipating communities. However, the relationship between land area and quantity of tree canopy was stronger for nonparticipants than for participants, and overall percentage of canopy cover as well as mean percentage of canopy cover were higher in nonparticipating communities. TCUSA participants in Maryland have similar land areas, similar ethnic demographics, higher populations, and canopy coverage more closely related to population than land area when compared to non-TCUSA communities and are most likely to be found in an urban/suburban context, while non-TCUSAs are more likely to be found in a rural (agricultural/forest) context.

Key Words. Tree City USA; tree canopy cover; demographics.

The Tree City USA (TCUSA) program is a cooperative program of the National Arbor Day Foundation (NADF), the USDA Forest Service (USDA-FS), and the National Association of State Foresters. The program provides recognition to communities that meet four standards in a given year: (1) Presence of a tree board or department legally responsible for care and management of a community's trees, (2) a community tree ordinance that designates the tree board or department as responsible for care and management of trees, (3) community forestry expenditures of at least US$2.00 per capita, and (4) an Arbor Day observance and proclamation (Fazio 1992). The TCUSA Growth Award is a related recognition provided to communities for demonstrating higher levels of achievement in funding, planning and management, tree planting and maintenance, education and public relations, or partnerships in a given year (USDA Forest Service 2004).

In 2002, more than 3.9 million people in the state of Maryland, U.S., approximately 73.5% of the state population, lived in 42 jurisdictions recognized as TCUSA communities. These communities spent over US$15 million on local urban and community forestry (UCF) programs.

According to NADF, benefits of TCUSA participation include publicity, public image, citizen pride, and education (Fazio 1992). The program provides an excellent opportunity for education and dissemination of information related to the benefits of trees. While the program requires establishment of a tree ordinance and existence of a tree board or department empowered by the ordinance supported by an annual budget of at least US$2.00 per capita for tree management activities, it is not known whether the program results in a level of tree protection and enhancement that results in an increase in tree cover.

Maco and McPherson (2002) reported that quantity of tree canopy cover is related to quantity of tree benefits and that an increase in canopy provides a correlated increase in benefits such as energy savings; air, soil, and water quality improvement; carbon sequestration; stormwater management; and an increase in appraised real estate values.

The United States Code section that authorizes funding for the national UCF program reports that "... urban trees are 15 times more effective than forest trees at reducing the buildup of carbon dioxide and aid in promoting energy conservation through mitigation of the heat island effect in urban areas. ... Tree plantings ... in urban areas and communities can aid in reducing carbon dioxide emissions, mitigating the heat island effect, and reducing energy consumption, thus contributing to efforts to reduce global warming trends." Among the purposes of the UCF program are to "... improve understanding of the benefits of preserving existing tree cover in urban areas and communities, ... encourage owners of private residences and commercial properties to maintain trees and expand forest cover on their properties, ... [and] provide education programs and technical assistance to state and local organizations (including community associations and schools) in ... identifying appropriate tree species and sites for expanding forest cover" (U.S. Congress 2002).