Back to the Mar-Apr 2020 issue

How Did Your City Complete a Tree Inventory?

Photo of Julie MooreJULIE MOORE
Communications And Recycling Coordinator
Shorewood (Population 7,708)

The Shorewood City Council voted in 2011 to participate in the Minnesota GreenStep Cities program in an effort to channel sustainability efforts and implement best practices.

Understanding our urban forest

To help meet our environmental management goals, the city Planning and Inspection Services Department recommended a public spaces tree inventory. The widespread concern about emerald ash borer (EAB) accelerated the need to have a better understanding of Shorewood’s forestry.

Building Inspector Joe Pazandak began the process of documenting the number and health of trees in parks and public properties.

The information was compiled into a GIS system that gave us a good base to determine how the city would budget for the future of EAB and other tree disease mitigation. The initial inventory took approximately five years to compile. A major challenge was limited staff time. One staff member can only cover so much ground.

A 10-year plan

When the majority of the city inventory was complete, and the information was reported to the Council, a local tree company, hired to handle diseased trees, was also asked to inventory the remaining areas. Then, a 10-year tree management plan was developed and approved by the Council. We are also taking steps to better maintain our tree inventory. A recent grant received through Hennepin County will help us add the tree inventory as a layer of the city GIS maps. In addition, we are upgrading the city’s GIS tools to allow Public Works employees to update the inventory when they are in the field removing or planting trees. They will also be able to document when they perform EAB treatments and other maintenance work.

Useful information

The tree inventory is already providing useful information. The tree canopy not only affects the aesthetics of our community, but the trees have a great impact on our stormwater and renewable energy goals. Knowing the location of many large ash trees in relation to other trees and structures has helped determine which trees should be removed and which should be treated. All the information gives us a more complete picture and helps us make important environmental decisions.

Photo of Andrea LauerANDREA LAUER
Royalton (Population 1,237)

In the City of Royalton, we love our trees and we’re committed to keeping them healthy. Royalton was designated as a “Tree City USA” community in 1985 by the Arbor Day Foundation, and the city has maintained that designation ever since.

Worried about EAB

We became concerned in 2009, when emerald ash borer (EAB) was discovered in Minnesota. The City Council decided we should do a tree inventory — or survey, as we called it — to help determine whether our trees were at risk. We partnered with the University of Minnesota Department of Forestry to do the tree survey in 2010. Our goal was to prepare for and manage infestations of invasive pests and diseases that would impact city trees.

Residents pitched in

The Tree Board enlisted resident volunteers to help with the survey. The U of M experts trained the volunteers and also actively participated in the survey. It included counting trees, identifying types of trees, determining the overall condition of each tree, and measuring trees. They did an excellent job of recording the data for future use. When examining trees on private property, volunteers had to explain to residents what they were doing and obtain permission to come onto the resident’s property. If the homeowner was not available, the volunteers did not go onto the property. Trees that could be seen from the street were recorded. Through this survey, we created baseline information on the health of our urban forest, which was great. We are still working to find a way to keep the data current.

Taking another look at ash trees

A student from the U of M Forestry Department contacted us in 2018 to follow up on the survey, and he asked specifically about the use of volunteers. It made us realize how important volunteers were to the tree survey and how we still rely heavily on volunteers for the care and planting of trees. The conversation prompted us to look at the data again since EAB was found in a neighboring county. We developed a tree management plan and used the data from the original survey to estimate how many ash trees we have that may be impacted by the disease. We want to keep our urban forest healthy, and we’re very grateful for the work of the Tree Board and citizen volunteers to help us do that.