|
Rapid Urban Site Index
Dr. Bryant Scharenbroch
University of Wisconsin- Stevens Point
Healthy urban trees require healthy urban soils! Soil assessment is a critical component of urban tree management. Soils in the urban environment are often degraded and extremely variable. Urban soil maps are not available and/or do not tell us about the soil suitability for urban trees. Consequently, arborists and urban foresters must assess soils for the trees they manage. A practical and accurate approach for soil assessment is needed for arboriculture and urban forestry.
An urban site index will help to improve urban forest diversity and urban tree health. Site quality identification will facilitate better matching of sites with species. Low quality can be planted with relatively tough trees, and high-quality sites can be planted with new species or trees with relatively weak or unknown resistance to urban stress. An urban site index will help identify poor quality soils in need of management for urban trees and can then be used to detect whether those management actions are effective at improving soil quality.
With support from TREE Fund we developed a practical and accurate site assessment for arborists and urban foresters (Scharenbroch and Catania, 2012; Scharenbroch et al., 2017; Scharenbroch et al., 2023). The first step in this process was to examine all the potential soil properties that could be measured and narrow down the list to the most influential soil properties for urban tree management. This list included soil texture, density, aggregate stability, pH, electrical conductivity, total organic matter, and labile organic matter (Scharenbroch and Catania, 2012). The second step included developing practical ways to assess these properties and compiling the information into an index. This index was called the Rapid Urban Site Index (RUSI) (Scharenbroch et al., 2017). The third step was to test the RUSI in other urban tree populations and make precision refinements (Scharenbroch et al., 2023).
The RUSI has taken over a decade of research to create and this work would not have been possible without TREE Fund. The RUSI is being used by arborists and urban foresters to assess soil conditions for urban trees. The RUSI has increased soil awareness and helped fill knowledge gaps of soil conditions impacting urban trees. We hope that RUSI has helped improve the quality urban trees and forests.
Work on the RUSI continues. We are in the process of working with practitioners to tailor the RUSI to specific urban tree populations towards optimizing its accuracy and practicality. For example, we have worked with the cites of Cambridge, MA and Kitchener, ON to modify RUSI for site assessment approaches for these tree populations. We are also utilizing the RUSI to understand unknown causes of urban tree decline. Specifically, we are utilizing RUSI to investigate the oak decline the Chicagoland area with the hopes of identifying specific site conditions that are predisposing oak trees in that area stress and decline.
If you are interested in learning more about RUSI or would like to work with us to develop and test your own site index, please contact me at bryant.scharenbroch@uwsp.edu.
This research would not have been possible without the generous support of the TREE Fund. We thank the TREE Fund and all of its supporters.
References
Scharenbroch, B.C. and M. Catania, M. 2012. Soil quality attributes as indicators of urban tree performance. Arboriculture and Urban Forestry 38:214-228.
Scharenbroch, B.C., Carter, D., Bialecki, M., Fahey, R., Scheberl, L., Catania, M., Roman, L.A., Bassuk, N., Harper, R.W., Werner, L. Siewert, A., Miller, S., Huytra, L., and S. Raciti. 2017. A rapid urban site index for assessing the quality of street tree planting sites. Urban Forestry and Urban Greening 27:279-286.
Scharenbroch, B. C., Scheberl, L., Gebhard, J. C., Prater, J. R., & Werner, L. P. (2023). Towards an Improved Rapid Urban Site Index. Arboriculture & Urban Forestry, 49(2).
| 
