What is Emerald Ash Borer and how does it kill ash trees?
The Emerald Ash Borer (EAB) is an invasive wood-boring beetle. It has devastated ash populations wherever it has become established. EAB has been found in several counties in Minnesota and Wisconsin, including Chisago and Douglas. EAB kills ash trees when the larvae under the bark become so extensive they prevent the flow of nutrients and water throughout the tree. This “girdling” starves all parts of the tree, killing it from the top down.
Why should I care about EAB?
All species of ash trees are susceptible to EAB, and millions of ash trees have been killed in infested areas already. Minnesota has one of the largest populations of ash in the U.S. with an estimated 900 million trees growing in urban and natural forests. The potential economic and environmental impacts of losing these trees are substantial. Where ash occur in home landscapes, the cost to remove and replace trees can reach into the thousands of dollars.
What impact could EAB have on the co-op’s system?
EAB will eventually kill ash trees throughout our service territory. Trees that are infested by EAB become very brittle and quickly break near ground level, creating a serious potential for widespread outages and damage to property. Arborists cannot climb infested trees because of the danger of failure, making removal difficult and expensive.
What steps is ECE taking to minimize the impact of EAB?
ECE has developed an EAB Management and Response Plan. The plan includes removing healthy ash trees before they become infested. We are learning from other utilities that it is critical to be proactive. EAB populations quickly expand, making a reactive approach unmanageable and less effective. ECE has already removed many healthy ash trees within quarantined counties near known infestation areas. We will also be strategically targeting ash tree removal in other areas of high ash density throughout the service territory. Trees are marked by one of our certified arborists, and the property owner is notified of the plan. A contractor will later remove the trees or take the tops out to prevent the outage risk. This process will take several years to complete.
Minnesota quarantine map
Wisconsin quarantine map
Is there anything ECE members can do to identify EAB and prevent it from spreading?
Since EAB kills by girdling the trunk in the larval stage, damage is not visible during the first year of infestation. Members should be on the lookout for woodpecker activity. The birds will feed on the larvae on the main trunk of the dead or dying tree. High value trees can be treated to protect them. If you are close to a known infestation, you may wish to consult a local arborist company for more information. The treatments are ongoing and can be quite costly. Begin planting trees now that can replace the ash trees in your landscape. However, don’t plant too close to ash trees or they could be damaged during removal operations.
Do not move ash materials, especially firewood. This is one of the most common ways for infestations to be moved to new locations. Please give ECE’s contractors your cooperation in removing ash trees.
If you don’t plan to treat your trees, we would like to remove them before they become infested.
Resources
Emerald Ash Borer Information Network
International Society of Arboriculture
Minnesota Department of Natural Resources