A Comprehensive Street Tree and Soil Study along Roadways in Oak Ridge, Tennessee

In the early 1940s, during the early stages of the Manhatttan Project (WWII), rural communities in Anderson County, Tennessee were rapidly converted into laboratory facilities and the city of Oak Ridge. The environment that became Oak Ridge not only experienced pollutants from the laboratory activities, but also alterations from the land-use change from rural to urban. Therefore, a study was conducted to determine the impacts of land-use change from rural to urban on (1) street tree diversity and performance; and (2) the biological, chemical and physical properties, and nutrient dynamics of street tree ecosystem soils. There were a total of 607 street trees, composed of 37 different species, on the five main roadways in Oak Ridge, Tennessee The street tree inventory revealed that the street tree ecosystems in Oak Ridge had a high relative abundance of Acer rubrum (21.91%)) and Pyrus calleryana (19.93 %). Chemical, rather than physical, soil and site properties in street tree ecosystems had the greatest impact on street tree performance. Also, the street tree ecosystem soils were significantly different from Knox County rural forest soils biologically, chemically, and physically. Soils in Oak Ridge differed street by street in their biological, chemical, and physical properties but were not influenced by traffic rates. There were also differences in soil microbial biomass carbon (MBC) during the winter on streets based on their diversity of trees; however, the most diverse street was among the lowest in soil microbial biomass. Seasonally, the winter proved to not only have greater amounts of soil microbial biomass carbon and nitrogen (MBN), but significantly less extractable organic carbon (EOC) and nitrogen (EON) and total labile carbon (TLC) than the spring. Overall, this study provided insights into the post urbanization impacts on the street trees, soils, sites, and nutrient dynamics within street tree ecosystems of Oak Ridge.