by G McPherson, JR Simpson, PJ Peper, SE Maco, Q Xiao
Journal of Forestry 103(8):411-4162005
City trees are often recognized as a best management practice for air quality improvement, stormwater runoff reduction, and energy savings. Municipal forest managers typically make cost-based budgeting decisions that intend to control expenditures while building improved urban forests, but these decisions tend to neglect the implications on the stream of ecological services produced by the urban forest. This paper assesses the importance of measuring these ecological services in order to effectively alter forest structure to enhance future benefits. The authors studied street and park tree populations in five United States cities to determine the relationships between structure, function, and value, and the utility of these analyses for urban forest planning and management. Using direct measurement strategies and numerical modeling techniques via the Street Tree Resource Analysis Tool for Urban Forest Managers (STRATUM), the authors were able to collect data on tree health and site conditions, establish relations between various tree demographics, estimate growth rates, and calculate annual benefits. The total monetary benefits from the municipal forests ranged from $665,856 to $3.25 million per year ($31 – $89/tree). The authors also determined that a robust young-tree care program is critical to ensuring that trees transition into healthy, well-structured mature trees. Based on these findings, urban forests are a valuable community asset whose future benefits will depend on a well-planned cultivation of a diverse functionally productive tree species. Urban forest managers could potentially find great success in targeting management efforts to regulate costs and maximize benefits by accounting for the ecological services produced by city trees.