Most people know that trees provide oxygen which we need to breathe, but did you know that trees also:
- Capture fine particles on leaf surfaces, reducing the circulation of airborne particulate matter
- Provide shade, reducing impacts of daytime heat and production of ozone
- Reduce the urban heat island effect (the tendency for built-up urban areas to retain more heat)
- Increase stormwater absorption and groundwater recharge
- Reduce rates of crime and stress
- Increase property values
- Promote outdoor exercise
- Provide natural habitat
- Enhance the landscape
- Offer an effective strategy for climate adaptation
So what will happen when Saint Paul loses 1 out of every 5 of its trees due to the invasive emerald ash borer?
Analyzing an emerging threat
The emerald ash borer (EAB), an invasive species native to Asia, was first found in Saint Paul in May 2009. If the EAB infestation mirrors results from elsewhere, all ash trees —20% of Saint Paul’s urban forest — will need to be removed. In 2014, the Minnesota Pollution Control Agency (MPCA) conducted a health impact assessment (HIA) of Saint Paul’s EAB Management Plan, by analyzing projected major tree loss and its impact on human health. The HIA illuminates the human health implications of Saint Paul’s EAB infestation and offers health-supporting recommendations for future urban forestry program decisions. This HIA can help forestry staff and other city officials in making program and funding decisions for the city’s management of EAB. More broadly, the assessment connects the health of a city’s urban forest with the health of its citizens, and will be relevant to future significant projected losses to the urban forest, including a 32% chance that another highly destructive borer species will invade the U.S. in the next 10 years.
The value of ash trees in Saint Paul
Urban trees contribute significant benefits to Saint Paul, and according to iTree calculations based on the city’s tree inventory, ash trees alone contribute over $2.5 million worth of health and other benefits each year, including:
- $138,847 of air quality services
- $922,044 of stormwater mitigation
- $691,126 of aesthetic and other benefits
Download the full report to view the detailed analysis, including projected implications, health pathways, and recommendations.
What is a health impact assessment (HIA)?
HIA is an emerging tool used to project the impacts to human health of a proposed program or policy change.
HIA is a systematic method that uses data, scientific research, evidence, and stakeholder input to determine how a proposed policy or project would impact health. HIA is a systematic process that uses an array of data sources and analytic methods and considers input from stakeholders to determine the potential effects of a proposed policy, plan, program, or project on the health of a population and the distribution of those effects within the population. HIA provides recommendations on monitoring and managing those effects. (National Research Council, 2011) An HIA can provide recommendations to increase positive health outcomes and minimize adverse health outcomes. HIA brings potential public health impacts and considerations to the decision-making process for plans, projects, and policies that fall outside the traditional public health arenas, such as transportation and land use. (Centers for Disease Control and Prevention, 2014)
For more information
About health impact assessments: www.cdc.gov/healthyplaces/hia.htm
About the emerald ash borer and how you can help: Are green aliens destroying your ash trees?
About trees and climate change https://www.arborday.org/globalwarming/treeshelp.cfm and http://www.theatlantic.com/technology/archive/2015/02/the-best-technology-for-fighting-climate-change-trees/385304/