Carbon stocks in urban forest remnants: Atlanta and Baltimore as case studies

Differences in urban environments can substantially affect the carbon cycle, for example, warmer temperatures, higher concentrations of CO₂, and greater nitrogen deposition can increase productivity over what would occur in surrounding areas. At finer scales, leaf-litter deposition and decomposing organisms become important. This chapter presents a conceptual framework to model how urban impacts and urban landscape management affect the C/N cycle, including the soil and plant carbon and nitrogen pools. Among the effects considered are decay rates, responses to pollution stress, the presence of invasive species, and changes in leaf litter composition and quality. The cities of Atlanta and Baltimore are presented as case studies on the net effect of urbanization on carbon stocks. Results from earlier i-Tree Eco studies of the cities were used with a focus on the results derived from the “forest” land use. Urban forest remnants in both cities have a high carbon density (i.e., amount of carbon per unit of land), but because this land use represents only a small fraction of each city, total carbon storage in forests is lower than other land uses.