Urban Forestry EAB Management Plan (River Falls)

The Situation

The city of River Falls is home to a high population of ash trees, many of which are considered high value. They experienced their first identified EAB case July 1, 2019. Ash tree mortality is near 100% within approximately 1-2 decades after EAB introduction, and tree decline and mortality becomes exponentially higher after approximately 5-7 years from identification in a specific location. River Falls needed a response plan, so Eocene was brought in to conduct an assessment and develop the response plan, including a solution to the insect infestation and eminent loss of a significant portion of the tree population. Ten issues were uncovered that required action on, after surveying trees on public and private lands, trees in maintained and natural areas, tree removal and replacement options, communication and resources, and EAB treatment options.

Our Solution

Eocene developed a response plan as a comprehensive assessment of the city’s ash trees, along with an evaluation of their levels of EAB infestation, overall health condition, and characterization of their growing sites. Following the assessment, Eocene posed three elements as a solution to the infestation and eminent loss of a significant portion of the tree population, all with the goal to attack the pest early on. The response plan proposed a means to confront EAB on the community’s terms, rather than do nothing and let the insect continue devastating the tree population.

Elements of Response Plan

1. Update the tree inventory which found that ash trees comprised 25% of the total 8,000 public trees within the city’s canopy.
2. Conduct survey and develop detection strategy by examining signs and symptoms of EAB.
3. Introduce ash tree management policy, noting action steps for treatment, removal and replacement of specific trees within the canopy.

Project Scope

With an overall goal to determine tree suitability for protective treatment against EAB, four steps were developed:

1. Project Kickoff
2. Implement project with kickoff meetings with community tree board and city staff in the field to explain project and calibrate the inventory methods.
3. Field Assessment to Gauge EAB Infestation Level
4. Conduct a field assessment of approximately 1,400 ash trees to determine the EAB infestation level and overall condition rating as customized to the needs of the city and recorded in the city’s ArcGIS software.
5. Next Steps Recommendation Report
6. Develop and submit a final report with recommendations on how to manage the city’s ash tree population.
7. Individualized Maintenance Recommendations
8. Create a spreadsheet with individual ash tree maintenance recommendations.