A Soil Management Toolbox for Urban Trees

2016 | Dr. Bryant Scharenbroch, University of Wisconsin – Stevens Point and Dr. Les Werner, University of Wisconsin- Stevens Point

In order to improve soil management for urban trees we need better assessment tools. However, not all urban tree managers require and can utilize the same soil assessments. For example, urban foresters may require coarser information on many planting sites. They would use this information to better match site conditions with species preferences to maximize diversity. Alternatively, arborists may be interested in seasonal patterns in the concentrations of nutrients in soil and tissues to develop prescription growth management recommendations. The goal of the proposed research is to develop three soil assessment models for urban tree managers to be included in a soil management toolbox. The first model, Urban Site Index (USI) is a field-based model that could be employed by the urban forester for a planting plan. Our most detailed model (USI++) would fulfill the objectives of an arborist wishing to develop a prescription fertilization plan. The last model (USI+) is intermediate in detail and cost and might be used by either the arborist or urban forester to assess soil conditions for urban trees. We have designed three experiments to develop and test these models. We also describe plans for collecting additional data for future refinement of the models. The models will be packaged in a user friendly and freely-available platform. Products from this research including three scientific manuscripts, workshops and presentations are described. Lastly, the research will train two graduate students and many undergraduates to grow the field of scientists in urban forestry, arboriculture and urban soil science.

Study Results

Students at the Soil Quality Assessment Workshop at the 2018 International Society of Arboriculture in Columbus, OH.

This project has significantly advanced the science of field assessment of site conditions for urban trees. From this research, we have developed and tested a practical model to accurately predict tree health based on urban site conditions. The model we have developed involves quickly assessing the soil quality, urban, and climatic factors driving tree health. A major finding of this research was that we learned that it is imperative to tailor our model to each user’s specific sites and challenges to urban trees. We are currently working with practitioners using the model to tailor it to their landscapes. This tailored approach will increase the accuracy of the model for each user.

An accurate and practical site assessment model will benefit urban trees in two major ways. Firstly, we can use it to better match site conditions to species tolerances and consequently increase the diversity of the urban forest. This can be done by planting relatively “tough” trees only in poor sites and relatively “weak” trees in highest quality sites. Secondly, many urban sites are degraded and require some management to improve their conditions. This model will allow us to better assess the efficacy of management actions to ensure what we are doing to the soil is actually improving its quality.

Luke Scheberl measuring available growing space as part of a site assessment for an urban tree.

This project has directly impacted both the science and practice. The results from this project have been presented at 21 practitioner and science based conferences. To date, we have published one peer-reviewed scientific manuscript and one M.S. thesis. We have three additional publications from this research that either in review or in preparation for publication in scientific peer-reviewed journals. We also have one additional M.S. thesis in preparation.

This project has provided research opportunities to graduate and undergraduate students at the University of Wisconsin-Stevens Point. This project has funded two M.S. graduate students. Additionally, this project has introduced seven undergraduate students to research in soil science, arboriculture, and urban forestry. Many of these students came from other areas of study, such as ecosystem restoration, waters, etc. Because of this project most these students have been introduced to urban tree and soil science. These students have developed an appreciation and hopefully an interest to pursue urban tree and soil science in their careers.

Year: 2016

Funding Duration: 3-5 years

Grant Program: Hyland R. Johns

Grant Title: A Soil Management Toolbox for Urban Trees

Researcher: Bryant Scharenbroch and Les Werner

Key words: Right tree in the right site, Urban forest planning, Urban tree health, Urban soil

Peer Reviewed Publications from Grant:

General Audience/Trade Publications:

Presentations:

  • Scharenbroch, B.C. and L. Scheberl. 2018. Rapid urban site index. Presentation at International Society of Arboriculture. Columbus, OH. 08/07/18.
  • Scheberl, L., Scharenbroch, B.C., and J.C. Gebhard. 2018 Can Soil Carbon Assessments Improve the Rapid Urban Site Index? Poster at International Society of Arboriculture. Columbus, OH. 08/06/18
  • Scheberl, L., Scharenbroch B.C., Werner, L.P., Prater, J.R., and K. Fite. 2018. Comparing Field Measurement Methods of Soil pH and Moisture for Use in an Urban Site Assessment. Poster at International Society of Arboriculture. Columbus, OH. 08/06/18.
  • Scharenbroch, B.C. Scheberl, L., and L. Werner. 2018. Soil quality assessment and management for urban trees. Workshop at International Society of Arboriculture. Columbus, OH. 08/02/18.
  • Scharenbroch, B.C., and S. Day. 2018. The dirt on urban soils. Workshop at Trees Florida. Ft. Myers, FL. 06/11/18.
  • Scheberl, L., Scharenbroch B.C., Werner, L.P., Prater, J.R., and K. Fite. 2018. Comparing Field Measurement Methods of Soil pH and Moisture for Use in an Urban Site Assessment. Poster and presentation at Minnesota Shade Tree Short course. Arden Hills, MN. 3/13/18.
  • Scheberl, L., Scharenbroch B.C., Werner, L.P., and J.R. Prater. 2018. Evaluating the Rapid Urban Site Index in Three Wisconsin communities. Presentation at Wisconsin Arborist Association. Green Bay, WI. 02/20/18
  • Scharenbroch, B.C. 2018. Soils 101. Presentation at Wisconsin Arborist Association. Green Bay, WI. 02/19/18.
  • Scharenbroch, B.C. 2018. A rapid urban site index for assessing the quality of street tree planting sites. Webinar for University of Massachusetts Extension Urban Forestry Today. 11/9/17.
  • Gebhard, J., Scheberl, L., and B.C. Scharenbroch. 2017. Can a Soil Carbon Assessment Predict Soil Biological Conditions Toward Improving the Rapid Urban Site Index for Urban Tree Management? Poster at Soil Science Society of America. Tampa, FL. 10/23/17.
  • Scharenbroch, B.C. 2018. A rapid urban site index for assessing the quality of street tree planting sites. Presentation at Soil Science Society of America. Tampa, FL. 10/23/17.
  • Scheberl, L., Scharenbroch B.C., Werner, L.P., Prater, J.R., and K. Fite. 2017 Field Measurement Methods of Soil pH and Moisture for Use in an Urban Site Assessment. Poster at Soil Science Society of America. Tampa, FL. 10/23/17.
  • Scheberl, L., Gebhard, J.C., and S. Stein. 2017. Field Methods to Assess Soil Moisture and pH. Presentation at Wisconsin Arborist Association. Madison, WI 08/15/17.
  • Scharenbroch, B.C. 2017. Soil compaction and urban trees. Presentation at International Society of Arboriculture. Washington, DC. 08/01/17.
  • Scharenbroch, B.C. 2017. In-field soil assessment for urban trees. Presentation at American Society of Consulting Arborists. Stevenson, WA. 12/02/17.
  • Scheberl, L., Scharenbroch, B.C. and K. Fite. 2017. A comparison of soil moisture and pH field meters for urban soils and trees. Presentation at International Society of Arboriculture. Washington, DC. 08/02/17.
  • Lichtscheidl, A., Ebright, A., Schneyer, A., Gutknecht, B., Schmidt, S., and B.C. Scharenbroch. 2017. Is labile carbon the key to unlocking soil quality assessment? Poster at UWSP-CNR Undergraduate Research Symposium. Stevens Point, WI. 04/07/17.
  • Scharenbroch, B.C. 2016. Soil compaction and urban trees. Webinar for TREE Fund, Utah DNR, Division of Forestry, Fire & State Lands & Utah State University Forestry Extension. 11/30/16.
  • Scharenbroch, B.C., 2016. Soil management for urban trees. Presentation at International Society of Arboriculture, Hong Kong Chapter. Hong Kong, CN. 10/28/16.
  • Scharenbroch, B.C., 2016. Soil management for urban trees. Presentation at Shanghai Chenshan Botanical Garden. Shanghai, CN. 10/26/16.
  • Scharenbroch, B.C. 2016. A site index for urban trees. Presentation for City of Kitchener. Kitchener, ON. 08/25/16.

For more information on this project, contact the researcher via TREE Fund at treefund@treefund.org.