Scientists & Staff

David J. Nowak

David Nowak

Emeritus Research Forester
State University of New York, College of Environmental Science & Forestry
1 Forestry Drive, 5 Moon Library
Syracuse, NY, 13210-2778
Phone: 315-448-3212

Contact David Nowak

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Current Research

The goal of my research program is to investigate what makes up the vegetation in cities and town and what environmental or ecosystem services this vegetation provides to local and regional populations. The research initiates field studies and develops computer models to assess the urban forest structure, functions, and values for urban areas across the globe. One of the research goals is to integrate urban forest ecosystem services (e.g., air quality improvement) within various environmental regulations (e.g., Clean Air Act). Tools are also being developed to aid in management and planning decisions to sustain urban forest health and services. Long-term monitoring programs are investigating how and why urban forest change through time so better management plans can be developed to sustain this important resource. Specific research projects include:

  • Assessments of changes in urbanization and urban forest structure and functions nationally
  • Local assessments of urban forest structure and functions: air pollution removal; carbon storage and sequestration; biogenic emissions; building of energy conservation; water flows and water quality; air temperatures
  • Effects of urban forests on air and water quality, energy use and air temperatures nationally
  • Long-term monitoring of urban vegetation locally and nationally (Urban Forest Inventory and Analysis Program)
  • Development of i-Tree ( computer model to assess urban forest structure, function, and value
  • Functional species selection program

Research Interests

Research interests focus on urban forest structure, health and change, and its effects on human health and environmental quality. Research is integrated with in the i-Tree modeling suite that quantifies the benefits and values from forests globally.

Past Research

Assessment of Oakland's Urban Forest: First detailed assessment of a city's entire forest system and associated ecosystem services based on complete field sampling. (1989-1991).

Chicago Urban Forest Climate Project: Expanded detailed assessment of urban forests and ecosystem services in the Chicago metropolitan region (2 counties). (1991-1994)

Development of Urban Forest Effects (UFORE) model: A standardized method of sampling of urban forests and methods of assessing ecosystem services was developed within a new model (UFORE) to aid in assessing and understanding urban forests. (1994-2004)

Urban Tree Effects on Ozone: A field and modelling study of urban tree effects on ozone concentrations along the Northeastern seaboard in the United States. (1998-2000)

National and Regional Effects of Urban Forests: National estimates of the magnitude of the U.S. urban forest resource and its impacts on air pollution removal, carbon storage and sequestration, and building energy use have been assessed and updated over the years. Also various threats to the urban forest at the national scale have been assessed. (2001-date)

National Urban Forest Health Monitoring: Helped lead a team that developed and tested field protocols and analyses techniques for assessing urban forests within a field plot inventory and monitoring program. Work from this project would be implemented within the current national urban forest inventory program in the United States. (2001-2013)

Development of i-Tree ( Numerous urban forest assessments of ecosystem services and values across the globe have been conducted using i-Tree Eco and other i-Tree tools. (2004-date)

Tree cover and cover change analyses: based on various field data and aerial assessments of urban area, research has been on-going on developing methods and quantifying change to urban forest structure and functions through time. (2004-date)

Why This Research is Important

As urbanization continues to alter our environment, the understanding and management of trees and forests in and around urban areas is essential to provide optimal forest services and values to current and future generations to sustain environmental quality, human health and human well-being.


  • University of California, Berkeley, Ph.D. Urban Forestry, 1991
  • SUNY College of Environmental Science and Forestry, M.S. Urban Forestry, 1986
  • SUNY College of Environmental Science and Forestry, B.S. Forestry and Biology (dual degree), 1984

Professional Experience

  • Senior Scientist / i-Tree Team Leader, USDA Forest Service 2016 - Current
  • Project Leader / Research Forester, USDA Forest Service 1997 - 2016
  • Research Forester, USDA Forest Service 1991 - 1997
  • Forestry Technician, USDA Forest Service 1989 - 1991

Professional Organizations

  • International Society of Arboriculture
  • Society of American Foresters (SAF)

Awards & Recognition

  • L.C. Chadwick Award for Arboricultural Research (ISA), 2015
  • R.W. Harris Author’s Citation (ISA), 2011
  • J. Sterling Morton Award (Arbor Day Foundation) , 2010
  • Research and Development Honor Award (US EPA), 2010
  • New York State Arborists, ISA Chapter Research Award, 2009
  • Trees Forever Special Recognition Award, 2009
  • Chief’s Honor Award for Engaging Urban America (i-Tree Team), 2008
  • Northern Research Station External Technology Transfer Award (Carbon Tools Development Group), 2008
  • Contributing member of Noble Peace Prize winning Intergovernmental Panel on Climate Change, 2007
  • Northern Research Station External Technology Transfer Award (i-Tree team), 2007
  • Distinguished Science Award for Northeastern Research Station, 2003
  • Chief’s Award for Excellence in Technology Transfer (group award for Memorial Trees), 2003
  • Chief’s Award for Excellence in Technology Transfer (group award for National Technology Transfer Te, 2003
  • State of New Jersey Green Community Achievement Award – Individual Category, 2002
  • APHIS award for outstanding contribution to the Solid Wood Packing Materials, 1999
  • American Forests Urban Forest Medal recognizing outstanding national contributions in urb.for. res., 1995
  • Freidrich U. Klaehn Memorial Award (SUNY ESF), 1985

Featured Publications & Products

Publications & Products

National Research Highlights

New York City skyline.

In New York City, the Value of Urban Trees Adds Up

Year: 2019

New York City’s urban forest produces cleaner air, lower energy costs, reduced ultraviolet radiation, and less storm water in the city’s sewer system. USDA Forest Service scientists and partners analyzed a sample of the city’s 7 million trees and found that they provide services with an annual value of more than $100 million.

Tree cover change in urban areas by state

Declining U.S. Urban Tree Cover

Year: 2018

Urban forests in the United States conservatively provide over $18 billion in annual benefits. Between 2009 and 2014, tree cover in urban areas dropped from 40.4 percent to 39.4 percent with 44 states showing a decline in tree cover. Total net loss of benefits is estimated at $96 million per year.

i-Tree user distribution by country.

i-Tree grows to more than 180,000 users in 130 countries

Year: 2017

i-Tree is a series of freely available tools that aid people in quantifying the benefits and values derived from trees and forests and in understanding local threats to forest health. Use of these tools continues to grow globally to aid in using trees to improve local environments and human health.

This map displays the current (2017) status of urban  FIA implementation.  Inventory monitoring has begun in those cities in bold font and the year the inventory began is also indicated.

Forest Inventory and Analysis Urban Monitoring Expands to Include 26 Cities

Year: 2017

In collaboration with state and local partners, the Forest Service’s Forest Inventory and Analysis (FIS) Program has expanded urban forest monitoring to include 26 cities. FIA recently crossed a major milestone with data collection underway in more than 25 percent of the program’s proposed cities, making urban inventories active in all four national FIA units.

Trees alter the microclimate around buildings and affect energy use.

Urban Trees Save Billions of Dollars Through Reduced Energy Costs

Year: 2017

Trees in U.S. urban and community areas reduce residential energy use by an average of 7.2 percent, which equates a national savings of $7.8 billion per year. Reduced energy use also lowers pollutant emissions from power plants, which equates to an additional $3.9 billion per year.

Urban forest species composition as a percentage of all trees, Austin, Texas. This data and more are included in FIA’s first published urban report: Austin’s Urban Forest, 2014. Tonya Lister, U.S. Department of Agriculture Forest Service.

Forest Inventory and Analysis is Coming to a City Near You

Year: 2016

In collaboration with state and local partners, the U.S. Forest Service’s Forest Inventory and Analysis Program (FIA) has begun monitoring the urban forest resource with special focus on the nation’s largest cities. FIA recently completed its first urban inventory report that describes the urban forests of Austin, Texas.

Estimated removal per square kilometer of land (tonnes km2) of all pollutants (NO2, O3, PM2.5, SO2) by trees per county in 2010. USDA Forest Service

Trees Improve Human Health and Save Lives

Year: 2014

Air pollution is a serious health concern. Trees offer surfaces that remove gaseous and particulate air pollutants. Modeling of local environmental data reveals that trees removed 17.4 million metric tons of air pollution across the conterminous United States in 2010, with human health effects valued at 6.8 billion dollars. The human health effects included the avoidance of more than 850 incidences of human mortality and 670,000 incidences of acute respiratory symptoms.

Trees in New York City Central Park. Dave Nowak, USDA Forest Service

Carbon Sequestration by Urban Trees Valued in the Billions of Dollars Annually

Year: 2013

Forest Service scientists quantified carbon storage and sequestration by urban trees in the United States to assess the magnitude and role of urban forests in relation to climate change. Total tree carbon storage in U.S. urban areas (in 2005) is estimated at 643 million metric tons ($50.5 billion value), with annual carbon sequestration estimated at 25.6 million tons ($2.0 billion value).

Infestation of European buckthorn (Rhamnus cathartica L.) on left with bush honeysuckle on right. Chris Evans, River to River Cooperative Weed Management Area,

Nature Dominates in City Tree Regeneration

Year: 2012

Assessment of tree planting and natural regeneration in cities reveals that most trees in cities are not planted

U.S. Urban Tree Cover Declining

Year: 2012

Analysis of aerial images reveals that U.S. urban areas are losing about 20,000 acres of tree cover per year

Urban and Community Forest Summaries for the Lower 48 States

Year: 2010

NRS scientist David Nowak and others have recently published several important summaries of tree and forest information.

Last modified: Tuesday, March 5, 2019