The city’s shade tree disease control program manages tree diseases such as Dutch elm disease and oak wilt on private and public property, in order to prevent epidemic-level outbreaks and actively prepares for emerging or new threats to the community forest such as emerald ash borer.
The city's natural resources staff provides consultation and inspection services to residents to diagnose and verify if a tree has Dutch elm disease, oak wilt, or emerald ash borer. Tree inspectors scout the city street by street throughout the summer, and fit in inspection requests when they reach the reported neighborhood.
Tree disease and insects of concern:
History of Minnetonka Shade Tree Disease Control Program
Minnetonka’s shade tree disease control program began in 1974 after Dutch elm disease (DED) appeared in Minnesota. By that time, DED had already infected and killed millions of elms east of the Mississippi River. In 1974, a total of 25 oaks and 26 elms were lost to disease in Minnetonka. In 1978, the peak year of the epidemic, Dutch elm disease killed 8,339 elms and oak wilt claimed 244 red oaks in our city.
The city has required property owners to remove diseased elms and red oaks from their land since that time. Details about the city ordinance can be found in the city code of ordinances. In 2007, the city began a cost-sharing program for diseased elms and red oaks along the road edge. Under this program, the city and the property owner are each responsible for half of the removal cost if the tree is located within the right-of-way.
Every year, between June and September, the city forester and 3-4 seasonal tree inspectors complete hundreds of initial tree inspections on public and private property in order to identify elms with DED and red oaks with oak wilt. In 2016, 626 elms and 51 red oaks were identified as diseased and marked for removal in Minnetonka. Every site is rechecked for compliance after the property owner’s deadline lapses. Each private property owner is notified with a door hanger when their property has met the city’s guidelines for disease control.
How To Report a Diseased Elm or Oak Tree
Call the forestry information line at 952-988-8407 between June 1–September 1, or fill out an online request form via Minnetonka Mike (click on the Forestry category and select “Dutch elm or oak wilt disease inspection”).
Provide the address of the site and a brief description of the tree(s) condition and location (near the street, in backyards, within outlots, etc.).
Anonymous Inspection Requests
Inspection requests are anonymous. Tree inspectors respond to requests, but also mark diseased trees they notice while scouting the city. Requested inspections will occur once a tree inspector reaches the reported neighborhood.
City Property Inspections
Tree inspectors scout the entire city for diseased elm and oak trees and take inspection requests. This includes city parks and outlots, schools, businesses, residential properties, county and state road edges, railroad properties and trail easements. Diseased trees marked on city properties are issued to one of several work crews, who must follow the same removal guidelines and timelines as private property owners. Sites are rechecked for compliance after the removal deadline lapses.
After Trees are Marked for Disease
After a tree is marked for disease, the following occurs:
- A letter is posted on-site.
- A letter is mailed to the property owner.
- Tree inspectors recheck the site for proper removal (30 days after initial marking for diseased elms, and after November 1 for diseased oaks).
Diseased Elm Trees - What to Look For
The city marks elms with Dutch elm disease (DED), which is a fungal disease that kills trees. Elms with DED typically have wilting and/or browning leaves in the upper portions of the canopy. Dead elms (including firewood) with tight bark are also marked for removal because, like standing trees, they create breeding sites for the beetles that spread the DED fungus. Dead elms without intact bark are no longer a disease risk and are not marked for removal. Good sanitation (removal of diseased trees) and chemically treating at-risk trees are the best strategies for managing Dutch elm disease.
There are chemical injections that may prevent Dutch elm disease from spreading to your elm trees. Click here to view the city's injection program brochure to learn more (pdf), or consult with your preferred tree care company.
No type of elm tree is immune to DED, though some have greater resistance. The disease may progress slower in Siberian elms, causing dieback over time instead of rapid and complete wilting and death. Forestry staff condemn Siberian elms with 50 percent or greater dieback because they become high risk breeding sites for elm bark beetles.
Diseased Oak Trees - What to Look For
The city marks select red oaks with oak wilt (OW), which is a fungal disease that kills trees. Only red oaks that have a capacity to produce a spore mat are marked for removal. Trees with OW typically have wilting and/or browning leaves in the upper portions of the canopy. Red oak firewood is not marked, but if you are required to remove a diseased red oak, you must debark it or properly dispose of the wood. White oaks are not marked for removal. Good sanitation (removal of diseased red oak trees), chemically treating at-risk trees, and root graft disruption with a vibratory plow are the best strategies for managing oak wilt.
Oak wilt is a fungus that affects red and white oaks differently. A red oak infected with the disease will generally wilt and die in the same season, while in white oaks the infection may affect the tree gradually over several years. Prompt therapeutic treatments (taking place from May-September) have been successful in minimizing the progression of the disease in infected white oaks. Forestry staff does not require the removal of white oaks with oak wilt.
Tree Inspections by the City of Minnetonka
Beyond Dutch elm disease and oak wilt, there are hundreds of other tree diseases, insects, disorders, and environmental conditions that can lead to a tree’s decline. At this time, the city only inspects elms, oaks and select ash on private property. As time permits, the city forester can provide over-the-phone guidance to residents with tree disorders/diseases other than Dutch elm disease and oak wilt.
Consider contacting a certified arborist to find out what is wrong with a tree. Click here for informational advice on hiring tree care professionals.
If the tree in question is dead or dying and is located in the right-of-way portion of your property, the city may inspect it and may prune or remove it for safety reasons. Report a dead or risk tree in the right-of-way by filling out an online request form via Minnetonka Mike (click on the Forestry category and select “Dead/risk tree on public property or along the road”).
Additional Informational Resources:
Removing Diseased Trees: Hiring a Tree Care Professional
View the Hiring Tree Care Professionals information for helpful tips and a list of contractors who work in Minnetonka.
Trees in the Right-of Way
The right-of-way is the portion of your property that borders the road edge. Although the street right-of-way is not listed as part of your property title, homeowners own the property under the right-of-way, generally to the centerline of the street. The city uses the right-of-way for snow storage, utilities, and trims trees that hamper visibility or safety along the road. If there is a diseased tree in your right-of-way that is marked for removal, the city will share the cost with you.
Trees and Property Lines
City tree inspectors determine property lines based on physical factors such as fences, mowing lines, overhead power lines (which generally mirror property lines), and our computer system that produces aerial photos showing parcel lines. In order to get the tree(s) reassigned to another property, you must show or explain the location of your property corners.
Please note: property line disputes are a civil matter
- Please try to resolve the dispute with your neighbor.
- If you cannot agree and would like more detailed information, you can visit the “public use” area at City Hall to see if there is a survey on file for your property. You can also hire a surveyor to find and mark your property stakes.
- You may also check out a metal detector at City Hall to locate the stakes. Call 952-939-8200 to see if one is available.
- If this research shows that a marked tree is on your neighbor’s property, please contact the forestry information line at 952-988-8407 so the records can be updated.
Disposing Diseased Elm and Oak Wood
For disposing of disease elm or oak wood, there are the following options:
- Bring the wood to the city’s free brush drop, located at 11522 Minnetonka Blvd.
- Brush is accepted only during normal brush-drop hours.
- The brush drop is open Mondays and Tuesdays from 11 a.m. to 7 p.m. and Saturdays from 7 a.m. to 3 p.m., mid-April thru mid-November.
- If you hire a contractor, they can also bring the wood to our drop-off free of charge, but you must accompany them. We use a large tub grinder to chip all of the wood into mulch.
- Brush is accepted only during normal brush-drop hours.
- Grind the wood and keep the wood chips on site for landscaping.
- Once the wood is chipped, it can no longer spread the disease.
- You may grind the wood yourself or pay your contractor to provide this service.
- Pay your contractor to haul the wood off site and dispose of it.
If the stump is in a high-traffic or grassy (mowed) area, you may want to consider removing it for aesthetic or safety reasons—but it is not necessary for disease control.
If you leave the stump in place, all the bark must be pulled back or removed from it. The city will not record the work as “complete” until all bark is removed from the stump.
This is a properly debarked stump.
Diseased Tree Removal Deadline Extensions
If you believe you will need an extension beyond the removal deadline, please contact the Natural Resources Division before your deadline has passed. The forestry information line, at 952-988-8407, is open Monday through Friday (you can leave a message any time). Extensions of up to one week will be granted on a case-by-case basis.
When calling, please provide the following information:
- Your property address and phone number.
- Reason for needed extension.
- Contact information for the tree service/contractor you have hired (an extension cannot be granted until you have hired a contractor, unless you plan to do the work yourself).
The site will be re-checked for completion after your extension deadline.
After Diseased Tree Removal
It is not necessary to notify our office. After the removal deadline has passed, a tree inspector or the city forester will revisit each address to confirm the removal of all diseased trees and wood.
Local Firewood Sources
Using locally produced firewood is more important than ever before. Click here to learn why local firewood is important and to find out where to buy it.
Visit the Minnesota DNR website to find out where to buy local firewood.