The Need for Field-Based Urban Tree Monitoring

Research Issue

[photo:] Felled London plane tree in northeast Philadelphia.

Urban forests are incredibly dynamic systems that change as people plant and remove trees. Researchers and professionals alike are often interested in assessing change over time in terms of mortality and growth rates, changes in tree health, and shifts in net population counts and species composition. For instance, managers may wonder about the rates of and factors associated with tree mortality in a planting program, or about whether new plantings are outpacing tree losses. Understanding such changes requires longitudinal data – that is, data tracking the fate of individual trees over time. While past studies from the USDA Forest Service and university researchers have generated copious longitudinal tree data for rural natural forest systems over many decades, such data is fairly new in urban settings. By tracking trees in specific neighborhoods, municipalities, or planting programs, monitoring studies can produce insights to guide urban forest management.

Our Research

Our research studies using field-based urban tree monitoring generate long-term data on tree mortality, growth, and health. Studies are done in close partnership with municipal foresters and non-profit urban greening staff to ensure that findings are relevant to program management. For example, citizen scientists monitor recently planted street trees with the Pennsylvania Horticultural Society in Philadelphia, PA, and students at Clark University and the University of Massachusetts, Amherst monitor yard trees planted by the Massachusetts Department of Conservation and Recreation. The findings of those studies are then used to understand planting program performance and develop strategies to boost survival. Many studies have pointed to the crucial role of maintenance and stewardship in young tree survival. Forest Service scientists and colleagues also published a literature review on urban tree mortality.

Furthermore, there are special considerations for urban tree monitoring in terms of field methods and data quality. For example, small-stature, low-forking, commonly multi-stemmed trees such as ornamental crabapples (Malus spp.) and cherries (Prunus spp.) are increasingly common in urban plantings, but these trees are not conducive to classic trunk measurement approaches, so we devised a study to determine the best way to measure multi-stemmed trees. We have also evaluated citizen science data quality for both young tree monitoring and street tree inventories.

Outcomes: Urban Tree Monitoring Guides

Forest Service researchers and colleagues have produced new technical guides about urban tree monitoring to assist other researchers, urban forestry professionals, community urban greening advocates, and students who wish to monitor the trees that they plant and manage. Specifically, we have a Field Guide with detailed protocols for data collection, including accurate tree locations and repeated measurements of trunk diameter to assess growth, and a Resource Guide with tips and strategies for implementing monitoring projects. These strategies include how to design a longitudinal database and tips for effective field crew training and supervision. We have also produced five training videos and a webinar about these new resources. These products serve as a launching point for anyone in urban forestry seeking to track trees over time.

Research Results

Magarik, Yasha A.S.; Roman, Lara A.; Henning, Jason G. 2020. How should we measure the DBH of multi-stemmed urban trees?. Urban Forestry & Urban Greening.

Roman, Lara A.; van Doorn, Natalie S.; McPherson, E. Gregory; Scharenbroch, Bryant C.; Henning, Jason G.; Ӧstberg, Johan P.A.; Mueller, Lee S.; Koeser, Andrew K.; Mills, John R.; Hallett, Richard A.; Sanders, John E.; Battles, John J.; Boyer, Deborah J.; Fristensky, Jason P.; Mincey, Sarah K.; Peper, Paula J.; Vogt, Jess. 2020. Urban tree monitoring: a field guide. Gen. Tech. Rep. NRS-194. Madison, WI: U.S. Department of Agriculture, Forest Service, Northern Research Station. 48 p.

van Doorn, Natalie S.; Roman, Lara A.; McPherson, E. Gregory; Scharenbroch, Bryant C.; Henning, Jason G.; Östberg, Johan P.A.; Mueller, Lee S.; Koeser, Andrew K.; Mills, John R.; Hallet, Richard A.; Sanders, John E.; Battles, John ; Boyer, Debra J.; Fristensky, Jason P.; Mincey, Sarah K.; Peper, Paula J.; Vogt, Jessica M. 2020. Urban tree monitoring: a resource guide. Gen. Tech. Rep. PSW-GTR-266. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 132 p.

Blair, Seth A.; Koeser, Andrew K.; Knox, Gary W.; Roman, Lara A.; Thetford, Mack. 2019. Visual health assessments for palms. Urban Forestry & Urban Greening.

Blair, Seth A.; Koeser, Andrew K.; Knox, Gary W.; Roman, Lara A.; Thetford, Mack ; Hilbert, Deborah R. 2019. Health and establishment of highway plantings in Florida (United States). Urban Forestry & Urban Greening.

Breger, Benjamin S.; Eisenman, Theodore S.; Kremer, Madison E.; Roman, Lara A.; Martin, Deborah G.; Rogan, John. 2019. Urban tree survival and stewardship in a state-managed planting initiative: A case study in Holyoke, Massachusetts. Urban Forestry & Urban Greening.

Hilbert, Deborah R.; Roman, Lara A.; Koeser, Andrew K.; Vogt, Jess ; van Doorn, Natalie S. 2019. Urban Tree Mortality: A Literature Review. Arboriculture & Urban Forestry: 45(5): 167-200.

Elmes, Arthur; Rogan, John; Roman, Lara A.; Williams, Christopher A.; Ratick, Samuel J.; Nowak, David J.; Martin, Deborah G. 2018. Predictors of mortality for juvenile trees in a residential urban-to-rural cohort in Worcester, MA. Urban Forestry & Urban Greening. 30: 138-151.

Roman, Lara A.; Smith, Bailey C.; Dentice, Dana ; Maslin, Mindy ; Abrams, Glen. 2018. Monitoring young tree performance with citizen scientists: The evolving Tree Checkers program in Philadelphia, PA. Arboriculture & Urban Forestry. 44: 255-265.

Roman, Lara A.; Scharenbroch, Bryant C.; Ostberg, Johan P.A.; Mueller, Lee S.; Henning, Jason G.; Koeser, Andrew K.; Sanders, Jessica R.; Betz, Daniel R.; Jordan, Rebecca C. 2017. Data quality in citizen science urban tree inventories. Urban Forestry & Urban Greening.

Campbell, Lindsay K.; Svendsen, Erika S.; Roman, Lara A. 2016. Knowledge Co-production at the Research-Practice Interface: Embedded Case Studies from Urban Forestry. Environmental Management. 57: 1262-1280.

Ko, Yekang; Lee, Jun-Hak; McPherson, E. Gregory; Roman, Lara A. 2015. Factors affecting long-term mortality of residential shade trees: evidence from Sacramento, California. Urban Forestry & Urban Greening. 14(3): 500-507.

Ko, Yekang; Lee, Jun-Hak; McPherson, E. Gregory; Roman, Lara A. 2015. Long-term monitoring of Sacramento Shade program trees: tree survival, growth and energy-saving performance. Landscape and Urban Planning. 143: 183-191

Roman, Lara A.; Scharenbroch, Bryant C.; Ostberg, Johan P.A.; Mueller, Lee S.; Henning, Jason G.; Koeser, Andrew K.; Sanders, Jessica R.; Betz, Daniel R.; Jordan, Rebecca C. 2017. Data quality in citizen science urban tree inventories. Urban Forestry & Urban Greening.

Roman, Lara A.; Walker, Lindsey A.; Martineau, Catherine M.; Muffly, David J.; MacQueen, Susan A.; Harris, Winnie. 2015. Stewardship matters: Case studies in establishment success of urban trees. Urban Forestry & Urban Greening. 14(4): 1174-1182.

Roman, Lara A.; Battles, John J.; McBride, Joe R. 2014. Determinants of establishment survival for residential trees in Sacramento County, CA. Landscape and Urban Planning. 129: 22-31.

Roman, Lara A.; Battles, John J.; McBride, Joe R. 2013. The balance of planting and mortality in a street tree population. Urban Ecosystems. 18 p. 10.1007/s11252-013-0320-5.

Roman, Lara A.; McPherson, E. Gregory; Scharenbroch, Bryant C.; Bartens, Julia. 2013. Identifying common practices and challenges for local urban tree monitoring programs across the United States. Arboriculture & Urban Forestry. 39(6): 292-299.

Research Participants

Principal Investigator

  • Lara Roman, Northern Research Station, USDA Forest Service, Research Ecologist
  • Natalie van Doorn, Pacific Southwest Research Station, USDA Forest Service, Research Urban Ecologist

Research Partners

  • Last modified: June 7, 2021