The Minnesota Pollution Control Agency, or MPCA, conducted an HIA on St. Paul's efforts to address the threat posed by the emerald ash borer, an invasive beetle destroying Minnesota's 930 million ash trees. Research shows strong links between tree cover and a range of health impacts. Trees filter pollutants and improve air quality, lowering rates of respiratory illness. Additionally, an urban tree canopy is one of the most effective ways to reduce the risk of health complications during a heat wave, such as asthma, dehydration, heat stroke, and cardiovascular-related deaths. The HIA also examined pesticide-use policies to minimize health impacts related to exposure. The report recommended that policymakers designate the city's urban forest a priority; set up a citizen volunteer program to meet the needs of the urban/community forestry program; offer incentives to businesses and property management companies to reduce heating and cooling costs; and identify target neighborhoods where planting more trees would be especially beneficial.
The HIA bolstered local services and programs that recruit, train, and engage citizen volunteers in urban tree management. The assessment elevated awareness of the health-related impacts of canopy loss. Additionally, the HIA process engaged local stakeholders in ways that influenced local decision-making. The report also influenced the decision to pilot a near-road vegetation project along Interstate 35E as a longer-term strategy to reduce fine particle pollution. The pilot project sparked wider interest in this approach. Finally, the HIA also resulted in stronger working relationships between state and local government agencies.