City dwellers around the world could live healthier lives and see health care costs shrink simply by implementing better urban forest design, planning and management.
Recent innovative studies conducted in Canada and the U.S. show that trees remove air pollution – both gaseous and particulate pollutants – and this has a beneficial effect on human health.
And, while the concepts of trees scrubbing the air and cleaner air having beneficial effects are not particularly new, “the innovation derives from linking pollution removal by trees to human health in cities,” said Dr. David Nowak of the US Forest Service, and one of the authors of the studies.
“We know the existing forest is already removing air pollution, but better designs and management could be used to produce further air quality improvements using trees and forests. This, in turn, would improve human health and significantly reduce associated health care costs,” he said.
“Computer simulations with local environmental data reveal that trees in 86 Canadian cities removed 16,500 tonnes of air pollution in 2010, with human health effects valued at $227.2 million Canadian dollars,” said Dr. Nowak.
In an earlier study of U.S. trees and forests nationally, again using 2010 as the base year, human health effects were valued at US $6.8 billion, and 17.4 million tonnes of air pollution were removed.
The Canadian government – Environment and Climate Change Canada – helped fund the more recent study (Air pollution removal by urban forests in Canada and its effect on air quality and human health) shortly after the 2014 publication of the assessment for the U.S. done by Dr. Nowak and his colleagues.
“All countries could use and benefit from this type of information,” Dr. Nowak said. “The processes of trees are fairly consistent across the globe, but the results will vary based on local environmental conditions and human and forest populations.
“A series of free tools is available to aid cities and forest managers globally in assessing their current forest structure and benefits (www.itreetools.org). We’ve now incorporated this particular process into the i-Tree Eco model to help managers estimate these and other effects and values from trees and forests,” he said.
i-Tree is a state-of-the-art, peer-reviewed software suite from the Forest Service of the USDA that provides urban and rural forestry analysis and benefits assessment tools. The i-Tree tools can help strengthen forest management and advocacy efforts by quantifying forest structure and the environmental benefits that trees provide.
Since the initial release of the i-Tree tools in August 2006, thousands of communities, non-profit organizations, consultants, volunteers and students around the world have used i-Tree to report on individual trees, parcels, neighborhoods, cities, and entire states.
By understanding the local, tangible ecosystem services that trees provide, i-Tree users can link forest management activities with environmental quality and community livability.
Dr. Nowak pointed out that trees provide multiple benefits in addition to pollution removal, so it follows that better urban forest design and management, in addition to improving human health and lowering health-related costs, could also reduce other urban problems and costs, such as energy use, flooding, high air temperatures, etc.
“If better forest designs and management are instituted to improve air quality, people living in cities everywhere should benefit,” he continued.
“Even though the percentage of air quality improvement is relatively small, these improvements in air quality impact human health,” said Dr. Nowak.
“Cities are not just people, buildings, roads and cars. They also have substantial amounts of natural elements such as trees, grass, soil, wildlife etc. that play essential roles within city environments,” he said.
Dr. Nowak said the role of natural elements within cities has been known for centuries. “But, to better incorporate these elements, we need to include them throughout the design, planning and management process of the cities.”
Cities would have to assess their current forest distribution and conditions. With that information and knowledge of tree effects on air pollution, specific management plans could be developed to maximize tree impacts on human health.
Policy makers, he said, should recognize that trees and forests within cities affect air quality and can be used to further improve that air quality. Investing in improving city forests and their management can yield improvements in human health and wellbeing and save money in the long run.
The full report can be found at: https://www.sciencedirect.com/science/article/pii/S1618866717302182
Dr. David Nowak is the coordinator of IUFRO Research Group 6.07.00 – Urban forestry: https://www.iufro.org/science/divisions/division-6/60000/60700/.
IUFRO All-Division 7 Meeting at the 125th Anniversary Congress
An Interview with Division 7 Coordinator Eckehard Brockerhoff of Scion (New Zealand Forest Research Institute)
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Supersites for Superior Forest Science
The initiative for establishing Supersites for forest research is only a few years old.
In these supersites, sophisticated, state-of-the-art instruments are used and a multitude of factors in the ecosystem is to be measured to obtain baseline data. As examples: spectrometers will measure how trees absorb and scatter light; laser scanners will map the forest’s three-dimensional structure; soil, plant and atmospheric sciences will be integrated; and mechanistic and policy-oriented modeling will be part of the concept. Read more…
Threats to Forest Health – Forest Pests and Diseases, Biological Invasions, Air Pollution and Climate Change
For more information on IUFRO Division 7 Forest Health: http://www.iufro.org/science/divisions/division-7/
The papers presented in this session addressed the relationship between changing climatic conditions and biotic factors such as bark beetles and wasps causing forest health problems of various degrees.
One paper highlighted present and projected changes caused by interactive impacts of increasing temperatures, ground-level ozone, nitrogen deposition, and CO2 on forests growth and soil and water processes in south-western and northern forests in the United States. These changes may predispose forests to altered water regimes, biodiversity insect attacks, wind-throw, frost damage and catastrophic fires.
Other presentations highlighted the effects of insects on forests in Northern and Central America. Generally, the number of severe outbreaks is increasing, but little is known about the causes of these calamities. Recent research clearly indicates, however, that several earlier benign insect species show damaging outbreaks because of increased stress on the ecosystem. Range expansions of e.g. bark beetle could also be observed and appear to be closely linked to changing climatic conditions.
A cost-benefit analysis of surveillance of ash borer population which is rapidly spreading in many regions due to international trade is worthwhile and cost-effective. Using bio-economic modeling on surveillance trapping helps to optimize surveillance and eradication programs. Given the increasing frequency and severity of insect outbreaks in Northern America continuous surveillance of invasive wood borers and bark beetles is also recommended for Latin America.
Presentations in this session:
Interactive effects of air pollution and climate change on forests in the United States (Andrzej Bytnerowicz, USDA Forest Service, USA)
Sirex noctilio in Argentina: What we know and still need to know to manage populations successfully (Juan Corley, Argentina)
A cost-benefit analysis of surveillance for invasive wood borers and bark beetles (Eckehard Brockerhoff, IUFRO Division 7 Coordinator, Scion, New Zealand)
Evaluation of mortality in natural stands of Pinus ocarpa an P. caribeae in Nicaragua (Lori Eckhart, Auburn University, USA)
The bark beetle outbreaks of Western North America (Christopher Fettig, Pacific Southwest Research Station, USA)
Second Session: Threats to Forest Health: Forest Pests and Diseases, Biological Invasions, Air Pollution and Climate Change
The main focus of the session was the impact of invasive species on forests and solutions for tackling these problems. Examples were given from different countries and continents including the US, South Africa, Argentina and New Zealand. Solutions are various and obviously depend on the respective case.
Common issues related to globalization and its impact on forest health were raised by all speakers. Live plant material, including seeds, have been implicated in many cases as pathways for invasions of alien pests and pathogens of forest trees and other plants. Solving this problem is difficult because many plants may be asymptomatic and infected plants may thus be difficult to exclude. Answering specific research questions, such as what type of organisms invade from where and related aspects, are required to allow informed decision-making. These are complex problems that require application of newest technologies and also require broad international collaboration.
Actions taken for integrated pest management include education of students, companies, pupils; communication with all stakeholders and the inclusion of locals in monitoring activities. Last but not least, training, early research including close collaboration and teamwork, the maintenance of quarantine facilities are keys to success.
It was recognized that in many countries, there is not good communication between forestry researchers and plant quarantine agencies that hold the responsibility for solving these problems. The group also concluded that the problem of biological invasions is perhaps not adequately recognized by the forestry research community, including within IUFRO. This suggests that there remains a need to educate the broader research community on the importance of this issue.
Presentations in this session:
Invasions by non-indigenous forest insects and diseases in the US (Andrew Liebhold, US Forest Service, USA)
Continuing spread of plantation pests and pathogens – is there a solution? (Jolanda Roux, University of Pretoria, South Africa)
Advances in IPM of a key pest of poplars in Argentina, Megaplatypus mutates (Mariana Moya, Universidad de Buenos Aires, Argentina)
Successful forest protection is a multifaceted endeavour (Tod Ramsfield, Natural Resources Canada)