David J. Nowak

David J. Nowak
US Forest Service | FS · Northern Research Station

Phd University of California, Berkeley

About

252
Publications
160,290
Reads
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Introduction
David Nowak is a Senior Scientist and Team Leader with the USDA Forest Service, Northern Research Station in Syracuse, NY. His research investigates urban forest structure, health, and change, and its effect on human health and environmental quality. He has authored over 300 publications and leads teams developing the i-Tree software suite that quantifies the benefits and values from vegetation.
Additional affiliations
January 1997 - October 2015
US Forest Service
Position
  • Project Manager
June 1994 - present
United States Department of Agriculture
Position
  • Group Leader
May 1994 - present
US Forest Service
Position
  • Project Manager

Publications

Publications (252)
Article
Different models as well as planting prioritization and optimization schemes based upon diverse ecological, social, and economic goals and preferences have been used to develop more efficient and effective tree planting schemes. We compare tree planting prioritization scenarios identified from i-Tree Landscape’s priority planting index to optimal s...
Article
Numerous threats to urban forests are assessed for the conterminous United States, including projected changes in urban tree cover, air temperatures, precipitation, aridity, sea level rise, wildfires, and flooding, as well as threats from hurricanes, tornadoes, ice storms, and insects and diseases. All potential threats were integrated into a cumul...
Article
Urban forests are recognized as a nature-based solution for stormwater management. This study assessed the underlying processes and extent of runoff reduction due to street trees with a paired-catchment experiment conducted in two sewersheds of Fond du Lac, Wisconsin. Computer models are flexible, fast, and low-cost options to generalize and assess...
Article
In the 1930’s the Federal Home Loan Bank Board established a program to appraise real estate risk levels in several cities. Four classes indicating level of security for real estate investments were developed: A (green) – best, B (blue) – still desirable, C (yellow) – declining, and D (red) – hazardous. Recent studies have shown that heat island ef...
Article
Trees provide critical contributions to human well-being. They sequester and store greenhouse gasses, filter air pollutants, provide wood, food, and other products, among other benefits. These benefits are threatened by climate change, fires, pests and pathogens. To quantify the current value of the flow of ecosystem services from U.S. trees, and t...
Article
Full-text available
Given the large and increasing amount of urban, suburban and exurban land use on Earth, there is a need to accurately assess net primary productivity (NPP) of urban ecosystems. However, the heterogeneous and dynamic urban mosaic presents challenges to the measurement of NPP, creating landscapes that may appear more similar to a savanna than to the...
Article
Full-text available
With the uncertainties that our societies are living with (the COVID-19 pandemic and climate change), it becomes essential to provide urban planners and decision-makers with state-of-the-art and user-friendly methodologies to incorporate ecosystem service considerations into their designs for resilient cities. In this regard, urban forests play a c...
Article
Full-text available
Maintaining a diverse urban forest that provides ecosystem services can promote urban sustainability and resilience to environmental change. Around the world, cities have taken to inventorying their urban trees and quantifying their ecosystem services but more so in industrialized counties than in Latin America. Here we describe the results of an i...
Conference Paper
Highlights • The model performed well in the validation period using both manual and automated calibration. • Predicted runoff reduction was 106 L/m 2 of canopy (10,226 L/tree), 61% higher than field estimated 66 L/m 2 (6,376 L/tree). • Additional field studies are needed to confirm or update model processes and parameter ranges.
Article
Heat-related mortality is one of the leading causes of weather-related deaths in the United States. With changing climates and an aging population, effective adaptive strategies to address public health and environmental justice issues associated with extreme heat will be increasingly important. One effective adaptive strategy for reducing heat-rel...
Article
Full-text available
Trees in the urban right-of-way areas have increasingly been considered part of a suite of green infrastructure practices used to manage stormwater runoff. A paired-catchment experimental design (with street tree removal as the treatment) was used to assess how street trees affect major hydrologic fluxes in a typical residential stormwater collecti...
Article
Hurricanes cause billions of dollars in damage annually in the United States and are projected to increase in intensity in the coming years. By exploring historical patterns of hurricanes and exposure of these hurricane-force winds across the landscape, areas of potentially high threat to future hurricane winds can be revealed. Combining potential...
Article
Tree pollen with allergenic potential in cities triggers nasal, skin, eye, and asthmatic allergic reactions in humans. Pollen is one of the most common allergy-causing inhaled substances. Tree species composition, cultivar selection and the proximity of certain trees to humans can influence allergic responses. Data from 53 cities or states from var...
Article
Full-text available
Trees and urban forests remove particulate matter (PM) from the air through the deposition of particles on the leaf surface, thus helping to improve air quality and reduce respiratory problems in urban areas. Leaf deposited PM, in turn, is either resuspended back into the atmosphere, washed off during rain events or transported to the ground with l...
Article
Full-text available
Figure 1.-Estimated annual emissions and removals by carbon pool for forest land remaining forest land in each of the conterminous 49 States in 2019 (MMT CO 2 Eq.). Note that points and uncertainties represented by confidence intervals (95 percent) reflect net flux for all carbon pools in each State. Negative estimates indicate net C uptake (i.e.,...
Article
Urban tree cover contributes to human well-being through a variety of ecosystem services. In this study, we focus on the role that trees can play in reducing temperature during warm seasons and associated impacts on human health and well-being. We introduce a method for quantifying and valuing changes in premature mortality from extreme heat due to...
Article
Full-text available
Extremely high temperatures, which negatively affect the human health and plant performances, are becoming more frequent in cities. Urban green infrastructure, particularly trees, can mitigate this issue through cooling due to transpiration, and shading. Temperature regulation by trees depends on feedbacks among the climate, water supply, and plant...
Article
Uncertainty information associated with urban forest models are beneficial for model transparency, model development, effective communication of model output, and decision-making. However, compared with the extensive studies based on the applications of urban forest models, little attention has been paid to the uncertainty of the output from these...
Chapter
Trees and forests affect local air temperatures directly through evapotranspirational cooling and by shading surfaces, and indirectly by storing carbon and helping to prevent pollutant emissions, which affect greenhouse gas concentrations. The greatest climate benefits relative to human populations tend to occur in urban areas. As urban areas expan...
Article
In response to the strategic plan required by the Agricultural Act of 2014, the USDA Forest Service Forest Inventory and Analysis (FIA) program is initiating a strategic inventory of the nation’s urban forests. The inventory is designed to provide timely and credible data on urban forests, thereby meeting an expanding need for information on trees...
Article
Full-text available
The distribution of urban ecosystem services (UES) is often uneven across socioeconomic groups, leading to environmental justice issues. Understanding the distribution of UES across a landscape can help managers ensure an equitable distribution of services. While many past studies have focused on the distribution of green spaces in relation to soci...
Article
Urban forests provide a variety of ecosystem services that influence environmental and social welfare, but variable distribution of urban tree canopy (UTC) within and among urban areas can lead to inequitable provisioning of these benefits. Variation in UTC among and within urban areas is associated with local development patterns and socio-economi...
Article
Full-text available
Urban forests provide different ecosystem services, such as the removal of atmospheric pollutants, carbon sequestration, water and microclimate regulation, and habitat for wildlife. This improves environmental quality and the well-being of the population. In this study, the structure of the urban forest of the Aburrá Valley was analyzed and its con...
Article
Full-text available
Crown widths of woody plant species growing in urban areas are of considerable importance as an overall indicator of health and also serve as an important factor for assessing leaf area and associated ecosystem services, such as carbon sequestration, air pollution removal, air temperature cooling, and rainfall interception. Unfortunately, assessing...
Article
Full-text available
Trees are known to provide various ecosystem services and disservices to urban communities, which can be quantified using models based on field and environmental data. It is often uncertain how tree structure and environmental variables impact model output. Here we perform a sensitivity analysis (SA) of i-Tree Eco, a common urban forest model, to a...
Article
Ecosystem accounts, as formalized by the System of Environmental-Economic Accounting Experimental Ecosystem Accounts (SEEA EEA), have been compiled in a number of countries, yet there have been few attempts to develop them for the U.S. We explore the potential for U.S. ecosystem accounting by compiling ecosystem extent, condition, and ecosystem ser...
Article
Full-text available
Obtaining accurate tree cover maps within cities is a first step toward managing for equitable access to their ecosystem services. For example, by removing air pollutants trees contribute to fewer health impacts, and tree cover expansion could extend these benefits by targeting the most polluted areas and vulnerable populations. To support strategi...
Chapter
Urban trees provide numerous benefits to society, as well as costs. One of the more important benefits of urban trees relates to their impact on surface stormwater runoff. Hydrologic models can serve to optimize land use planning and facilitate the inclusion of more tree cover for its hydrologic ecosystem services. Varying modeling methods and leve...
Article
Trees in cities provide numerous benefits to society by altering the local physical, biological and social environment, providing billions of dollars in annual benefits. How tree and other cover types vary and are changing globally within urban areas is currently unknown. Photo-interpretation was used to determine current urban cover (tree, impervi...
Article
Full-text available
This method paper explains the i-Tree Cool River model algorithms for simulating the response of river water temperature to urban greening. The model captures the warming and cooling impacts of urban development and restoration through a water and energy budget. The water budget includes river inflows from urban storm sewers and reservoirs, and the...
Article
Full-text available
Background and Objectives: The structural diversity of an urban forest affects ecosystem service provision, and can inform management, planning, as well as policy. Trunk diameter at breast height (DBH) is amongst the most common measures of tree structure due to its ease of measurement and strong relationships with other structural and non-structur...
Article
River water quality and habitats are degraded by thermal pollution from urban areas caused by warm surface runoff, lack of riparian forests, and impervious channels that transfer heat and block cool subsurface flows. This study updates the i-Tree Cool River model to simulate restoration of these processes to reverse the urban river syndrome, while...
Chapter
Trees impact surface stormwater runoff, soil moisture, streamflow, water quality, and air temperatures by intercepting precipitation (rain and snow), enhancing soil water infiltration, shading surfaces, and evapotranspiring water. These impacts affect human health and well-being. Many of these tree impacts remain to be more accurately quantified an...
Preprint
Trees provide critical contributions to human well-being. They sequester and store greenhouse gasses, filter air pollutants, and provide wood, food, and other products, among other benefits. However, global change threatens these benefits. To quantify the monetary value of US trees and the threats they face, we combine macroevolutionary and economi...
Article
Urban trees provide numerous benefits to society, but upon removal, this resource is underutilized and often considered a waste product to be discarded. However, urban trees have a potential to be utilized for various products, create jobs and an income stream for cities. The latest data on urban forests in the United States were used to estimate t...
Article
The Asian longhorned beetle (ALB, Anoplophora glabripennis) is an invasive pest species currently infesting major port cities in North America and Europe. There is limited knowledge regarding the pathways of movement across heterogeneous landscapes at local scales. This study models dispersal pathways using circuit theory in Worcester, Massachusett...
Article
Urban forest modeling is becoming increasingly complex, global, and transdisciplinary. Increased modeling of urban forest structure and function presents an urgent need for comparative studies to assess the similarities and differences between modeling techniques and applications. This paper provides a systematic review of 242 journal papers over t...
Poster
Full-text available
Extremely high temperatures are getting more frequent in cities and their potential impacts on human health and plant performance are increasingly worrying. Implementing urban green infrastructure, particularly trees, can mitigate this development due to cooling from evapotranspiration and shading. However, the effect is not linearly scaling with t...
Article
Full-text available
The problems associated with air pollution and higher air temperatures in cities have been known for over a century, but so have the impacts of trees and forests on improving air quality and regulating air temperatures. Science has advanced our understanding on the various ways that trees affect air quality and temperatures. Trees affect air qualit...
Chapter
Trees in cities affect air quality and greenhouse gases in numerous ways and consequently affect environmental quality and human health. Urban vegetation can directly and indirectly affect local and regional air quality by altering the urban atmospheric environment. The main ways that urban trees affect air quality and greenhouse gases are through...
Article
Trees provide ecosystem services such as air pollutant removal, carbon storage and sequestration, urban heat island reduction, stormwater runoff reduction as well as other socio-economic benefits. Large-scale tree plantings are occurring in many cities to increase tree canopy coverage as well as the health, economic and environmental benefits that...
Article
When healthy trees are removed, common methods of compensation are either monetary or replanting new trees. Accurate monetary compensation for large healthy trees is difficult to ascertain and often uses formulas based on tree attributes such as species, size, location and condition. Compensation based on leaf area is more direct as most tree value...
Article
Full-text available
The urban forest is a valuable ecosystem service provider, yet cities are frequently-degraded environments with a myriad of stressors and disturbances affecting trees. Vulnerability science is increasingly used to explore issues of sustainability in complex social-ecological systems, and can be a useful approach for assessing urban forests. The pur...
Article
Full-text available
Los bosques urbanos prestan diferentes servicios ecosistémicos, tales como la remoción de contaminantes atmosféricos, la captura de carbono, la regulación hídrica y microclimática, y la oferta de hábitat para la fauna silvestre. Esto mejora la calidad ambiental y el bienestar de la población. En este estudio se analizó la estructura del bosque urba...
Technical Report
Full-text available
An analysis of the urban forest in New York, New York, reveals that this city has an estimated 7.0 million trees (encompassing all woody plants greater than one-inch diameter at breast height [d.b.h.]) with tree canopy that covers 21 percent of the city. The most common tree species across public and private land are Norway maple, northern white-ce...
Article
Full-text available
U.S. urban land increased from 2.6% (57.9 million acres) in 2000 to 3.0% (68.0 million acres) in 2010. States with the greatest amount of urban growth were in the South/Southeast (TX, FL, NC, GA and SC). Between 2010 and 2060, urban land is projected to increase another 95.5 million acres to 163.1 million acres (8.6%) with 18 states projected to ha...
Article
Full-text available
Paired aerial photographs were interpreted to assess recent changes (c. 2009-2014) in tree, impervious and other cover types within urban/community and urban land in all 50 United States and the District of Columbia. National results indicate that tree cover in urban/community areas of the United States is on the decline at a rate of about 175,000...
Article
This paper explores predictors of juvenile tree mortality in a newly planted cohort in Worcester, MA, following an episode of large-scale tree removal necessitated by an Asian Longhorned Beetle (Anoplophora glabripennis, ALB) eradication program. Trees are increasingly seen as important providers of ecosystem services for urban areas, including: cl...
Chapter
Understanding the economic and environmental benefits of nature, in particular trees and forests, can lead to better vegetation management and designs to optimize environmental quality and human health for current and future generations. Computer models have been developed to assess forest composition and its associated effects on environmental qua...
Technical Report
Full-text available
An analysis of the urban forest in Houston, Texas, reveals that this area has an estimated 33.3 million live trees with tree canopy that covers 18.4 percent of the city. Roughly 19.2 million of the city’s trees are located on private lands. The most common tree species are yaupon, Chinese tallowtree, Chinese privet, Japanese privet, and sugarberry....
Article
Significant advances have been made in identifying, quantifying and valuing multiple urban ecosystem services (UES), yet this knowledge remains poorly implemented in urban planning and management. One of the reasons for this low implementation is the insufficient thematic and spatial detail in UES research to provide guidance for urban planners and...
Article
Full-text available
Urban trees perform a number of ecosystem services including air pollution removal, carbon sequestration, cooling air temperatures and providing aesthetic beauty to the urban landscape. Trees remove air pollution by intercepting particulate matter on plant surfaces and absorbing gaseous pollutants through the leaf stomata. Computer simulations with...
Article
A typology of urban vacant land was developed, using Roanoke, Virginia, as the study area. A comprehensive literature review, field measurements and observations, including photographs, and quantitative based approach to assessing vacant land forest structure and values (i-Tree Eco sampling) were utilized, along with aerial photo interpretation, an...
Article
Full-text available
Urban Tree Canopy (UTC) plays an important role in moderating the Surface Urban Heat Island (SUHI) effect, which poses threats to human health due to substantially increased temperatures relative to rural areas. UTC coverage is associated with reduced urban temperatures, and therefore benefits both human health and reducing energy use in cities. Me...
Technical Report
Full-text available
The urban forest of the Chicago Wilderness region, a 7-million-acre area covering portions of Illinois, Indiana, Michigan, and Wisconsin, will face direct and indirect impacts from a changing climate over the 21st century. This assessment evaluates the vulnerability of urban trees and natural and developed landscapes within the Chicago Wilderness r...
Article
Full-text available
The benefits derived from urban forest ecosystems are garnering increasing attention in ecological research and municipal planning. However, because of their location in heterogeneous and highly-altered urban landscapes, urban forests are vulnerable and commonly suffer disproportionate and varying levels of stress and disturbance. The objective of...
Technical Report
Full-text available
Trees in cities can contribute significantly to human health and environmental quality. In 2002, there were an estimated 26.9 million trees (36.9 trees / acre) within non-forested urban areas in Wisconsin. In 2012, the non-forest urban areas were reassessed based on 185 field plots. Urban forest attributes changed between 2002 and 2012 due, in part...
Article
Knowledge regarding Ecosystem Services (ES) delivery and the socio-ecological factors that influence their proficiency is essential to allow cities to adopt policies that lead to resource-efficient planning and greater resilience. As one of the matrix elements of urban ecological structure, vegetation may play a major role in promoting ES proficien...
Technical Report
Full-text available
An analysis of the urban forest in Philadelphia, Pennsylvania, reveals that this city has an estimated 2.9 million trees (encompassing all woody plants greater than 1 inch diameter at breast height [d.b.h]) with tree canopy that covers 20 percent of the city. The most common tree species are spicebush, black cherry, ash, tree-of-heaven, and boxelde...
Technical Report
Full-text available
An analysis of the urban forest in Austin, Texas, reveals that this area has an estimated 33.8 million trees with tree canopy that covers 30.8 percent of the city. The most common tree species are Ashe juniper, cedar elm, live oak, sugarberry, and Texas persimmon. Trees in Austin currently store about 1.9 million tons of carbon (7.0 million tons of...
Chapter
Full-text available
The U.S. North—the 20 states bounded by Maine, Maryland, Missouri, and Minnesota—have a greater forest cover (42 percent of land area) and population density (194 people per square mile) than other large regions of the nation. Ecological, social, and economic changes anticipated over the next 50 years will profoundly affect future forest management...
Chapter
Full-text available
In the 2010 Resources Planning Act (RPA) Assessment (2010 RPA), we reviewed trends in urbanization, reported on the percent tree cover in urban areas circa 2005, reviewed urban forest ecosystem services, provided preliminary estimates of carbon stored in urban forests, and reviewed threats to urban forest health