St. Anthony Village and WSB are working together to formulate a comprehensive emerald ash borer (EAB) management plan. Thirteen years since the invasive species was first detected in Minnesota, it has reached a critical state in the Twin Cities, devastating native ash tree populations.
What is EAB?
EAB (Agrilus planipennis Fairmaire) is a non-native invasive wood boring beetle with larvae that tunnel under the bark in the living tissue. This disrupts the tree’s ability to transport water and nutrients, eventually killing the ash tree. The greater the beetle population, the more tree death. As ash die from EAB, the wood becomes unstable becoming a public safety issue, and it is why communities like St. Anthony are prioritizing the health of their ash trees.
Large scale tree death also causes negative environmental impacts. With more than 1 billion ash trees in Minnesota, an organized and systematic approach helps distribute the impacts and ensures an orderly response while maintaining as many trees as possible.
Doing a Tree Inventory Analysis for St. Anthony Village
In 2022, St. Anthony Village, a first ring suburb of Minneapolis, Minnesota, was awarded a Minnesota Department of Natural Resources Preparing for EAB Grant and is now engaging with WSB’s forestry services to assist with their response.
St. Anthony had already started inventorying trees with a local non-profit organization using a previous grant award. It is about two-thirds complete and the results to date show that green ash account for about 7.5 percent of the total tree species composition on city property. The death of these ash trees is an adverse outcome for the city because trees serve as part of the community’s green infrastructure: they clean the air, slow down and absorb stormwater, reduce erosion, save electricity by reducing air conditioning costs, enhance property values, and provide habitat for wildlife.
WSB’s first step was to analyze the in-progress ash tree inventory data to determine the total number of ash and quickly assess if any of the condition ratings were high enough to merit protection with a systemic insecticide. The analysis revealed that more than half of the inventoried ash met the size and condition ratings to be preserved. Although St. Anthony Village has an above average tree canopy coverage, identifying ash that can be preserved is an important step to halt any further EAB-driven ash mortality. One figure provided by the Minnesota Shade Tree Advisory Council (MnSTAC) indicates the loss of all urban ash trees in the state will lead to 1.7 billion gallons of water entering our stormwater systems annually. While cities in the region have a tree canopy cover of 27.8 percent, the goal is for most cities is to have an average of 45 percent tree canopy coverage (Growing Shade mapping tool, Metropolitan Council 2022).
Creating an EAB Management Plan
WSB is continuing to support St. Anthony Village to understand their operations and capacity. These pieces will form the basis for a plan and future budget projections. Since each community has a different tree population, canopy cover, resident base, staff work responsibilities, budget constraints, and leadership/city council goals, each EAB management plan should be tailored to suit the specific needs of the organization. Doing so helps ensure it is a practical document that can help drive yearly work plans and budgets.
The next steps of the project will entail reviewing the existing dead/dying ash trees to determine removal priorities based on condition and location. In addition, the remainder of ash trees that are living but not eligible for preservation will be divided into a workable removal schedule, dependent on budget and staff time.
Beyond the management of ash trees, the other components of the plan will involve public outreach and education, reforestation/canopy replacement, and a review of policies/ordinances relating to ash and/or trees to ensure they match the proposed EAB management plan.