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Northern Research Station
One Gifford Pinchot Drive
Madison, WI 53726
(608) 231-9318
(608) 231-9544 TTY/TDD

Urban Natural Resources Stewardship

National Assessments of Urban Forests

[photo:] Forest Service scientist using clinometer to measure tree heightResearch Issue

To improve urban forest planning, management and policies at the local to national scale, information is needed on the extent of the urban forest resource, how it varies across the nation and how it is changing. This research combines top-down satellite analysis and national urban map data with local field data to help understand the magnitude and composition of this important resource, how urbanization is expanding, and factors that will lead to changes in tree species health and distribution in the future.  This information will lead to better regional and national policies and budgeting to improve environmental quality and sustain tree health in urban and urbanizing regions.

Our Research

[image:] Artwork for RPA- Resoorces Planning Act AssessmentOur research unit focuses on utilizing satellite or aerial-based technologies to assess urban tree cover distribution at the city to national scale. In conjunction with the aerial cover data, research investigates the best means to field sample urban areas to determine vital statistics such species composition and health, species diversity, and size-class distribution. These data are combined to produces estimates of urban forests composition and health, and associated ecosystem services at the local to nation scale. Long-term monitoring data are used to assess how the urban forest resource is changing, reasons for the changes, and likely changes in the future. National monitoring and assessments are part of the Resources Planning Act (RPA) Assessment program and the Forest Inventory and Analysis, and Forest Health Monitoring programs of the Forest Service. National urban forest field data collection is being pilot tested in various states across the United States as part of the Urban Forest Health Monitoring Program. Urban tree cover and ecosystem services at the national scale are being developed as part of the RPA program with the 2nd national urban forest assessment nearing completion.

Expected Outcomes

These national data are being used to assess the risk of various invasive pests in urban areas and develop strategies to sustain ecosystem benefits and urban tree cover for future generations.

Research Results

Links to the abstracts of select published articles:


Buckelew Cumming, A., D.B. Twardus, D.J. Nowak. 2008. Urban Forest Health Monitoring:Large- Scale Assessments in the United States. Arboriculture and Urban Forestry. 34(6):341-346.

Walton, J.T., D.J. Nowak, E.J. Greenfield. 2008. Assessing Urban Forest Canopy Cover Using Airborne or Satellite Imagery. Arboriculture and Urban Forestry. 34(6):334-340.

Buckelew Cumming, A., D.J. Nowak, D.B. Twardus, R. Hoehn, M. Mielke, and R. Rideout. 2007. Urban Forests of Wisconsin 2002: Pilot Monitoring Project 2002. USDA Forest Service, Northeastern Area State and Private Forestry Report, NA-FR-05-07.  33 p.

Nowak, D.J., A. Buckelew Cumming, D. Twardus, R. Hoehn, M. Mielke. 2007. National Forest Health Monitoring Program, Monitoring Urban Forests in Indiana: Pilot Study 2002, Part 2: Statewide Estimates Using the UFORE Model. Northeastern Area Report. NA-FR-01-07. 13 p.

Nowak, D.J., R.H. Hoehn, and D.E. Crane. 2007. Oxygen production by urban trees in the United States. Arboriculture and Urban Forestry. 33(3):220-226.

Nowak, D.J., D.E. Crane and J.C. Stevens. 2006. Air pollution removal by urban trees and shrubs in the United States. Urban Forestry and Urban Greening. 4:115-12.

Pouyat, R.V., I.D. Yesilonis, and D. Nowak. 2006. Carbon storage by urban soils in the United States. J. Environ. Quality. 35:1566-1575.

Nowak, D.J. and J.T. Walton. 2005. Projected Urban Growth and its Estimated Impact on the U.S. Forest Resource (2000-2050). J. For. 103(8):383-389.  

Nowak, D.J., J.T. Walton, J.F. Dwyer, S. Myeong, and L.G. Kaya. 2005. The increasing influence of urban environments on U.S. forest management. J. For. 103(8):377-382.

Walton, Jeffrey T. 2005. An investigation of national tree canopy assessments applied to urban forestry. Syracuse, NY: State University of New York College of Environmental Science and Forestry. 88 p. Ph.D. dissertation. 

Nowak, D.J. and D.E. Crane. 2002. Carbon storage and sequestration by urban trees in the United States. Environ. Poll. 116(3): 381-389.

Nowak, D.J. and J.F. Dwyer. 2002. Assessing the value of urban forests in the United States. In: 2001 Society of American Foresters National Conference Proceedings. Denver, CO. p. 237-241.

Nowak, D.J., D.E. Crane, J.C. Stevens, and M. Ibarra. 2002. Brooklyn’s Urban Forest. USDA Forest Service Gen. Tech. Rep. 290. 107 p.

Nowak, D.J., D.E. Crane, and J.F. Dwyer. 2002. Compensatory value of urban trees in the United States. J. Arboric.28(4): 194-199.

Nowak, D.J. and J.F. Dwyer. 2002. Urban forest structure and value at the national scale. Proc. of the National Urban Forest Conference. Washington, DC. p. 24-25.

Nowak, D.J., M.H. Noble, S.M. Sisinni, and J.F. Dwyer. 2001. Assessing the U.S. urban forest resource. J. For. 99(3):37-42.

Nowak, D.J., J. Pasek, R. Sequeira, D.E. Crane, and V. Mastro. 2001. Potential effect of Anoplophora glabripennis (Coleoptera: Cerambycidae) on urban trees in the United States. J. Econon. Entomol. 94(1):116-122.

Research Participants

Principal Investigators and Research Partners

  • David J. Nowak, US Forest Service Northern Research Station Project Leader and Research Forester
  • Eric Greenfield, US Forest Service Northern Research Station Research Forester
  • Robert Hoehn, US Forest Service Northern Research Station Forester
  • Jack Stevens, US Forest Service Northern Research Station Forester
  • Daniel E. Crane, US Forest Service Northern Research Station Information Technology Specialist
  • Chris Sorrentino, US Forest Service Northern Research Station Data Services Specialist GIS
  • Anne Cumming Buckelew, US Forest Service State & Private Forestry Northeastern Area Forester
  • Dan Twardus, US Forest Service State & Private Forestry Northeastern Area Group Leader
  • Angie Rowe, US Forest Service Southern Research Station Supervisory Forester



Last Modified: 10/03/2019