Emerald Ash Borer
Emerald ash borer (EAB) is an insect that attacks and kills all species of ash trees. The adults are small, green beetles that live outside of trees during the summer months. The adults lay their eggs on branches and in bark crevices. The eggs hatch into larvae, which tunnel underneath the bark to feed. As the tree becomes infested with EAB larvae, it begins to decline in health and die.
The Minnesota Department of Agriculture (MDA) has imposed a quarantine for several counties, including Washington County, prohibiting the movement of potentially infested items such as ash limbs, branches, and logs out of those counties. For more information on EAB in Woodbury or to inquire about the discounted treatment program available through Rainbow Treecare.
Questions can be directed to the Public Works Department at 651-714-3720 or via email.
Emerald Ash Borer Video
- What can residents do to mitigate the effect of expected tree loss due to the emerald ash borer?
Residents are encouraged to take steps to mitigate the effects of the expected tree loss across the city as well as be on the lookout for signs and symptoms of the emerald ash borer (EAB) infestation. Here is what you can do:
- Determine if you have ash trees on your property. Look for signs of EAB damage, which include dieback of leaves in the upper one-third of the tree's branches, heavy woodpecker activity, bark splitting, S-shaped larvae tunnels under the bark, or a significant amount of water sprouts on the trunk. If you suspect an EAB infestation, please call a certified tree service provider.
- DO not plant new ash trees. For a list of recommended trees to replant, visit the University of Minnesota Extension website.
- Consider removal of declining or small ash trees on your property now, especially if they are small enough to do the removal yourself. This may save on the cost of removal in the future. Keep in mind that most trees will require a professional to remove.
- To prevent the accelerated spread of adult beetles, MDA guidelines recommend pruning and removal of ash during the months of October through April when the EAB is dormant. If possible, avoid pruning and removal of ash trees during the months of May through September, when the EAB is active.
- You can find a list of compost sites in the county on the Washington County website. Tree removal companies usually will dispose of the tree for you. In order to prevent the spread of EAB, all ash wood should be properly destroyed within Woodbury.
- Early detection and preventive treatments with approved insecticides can prolong the life of an ash tree. Tree contractors with pesticide applicators licenses should be consulted to discuss treatment options. Before deciding to treat your tree, educate yourself about the pros and cons of these chemicals. The city recommends the trunk injection application method; the soil drench application method has a higher risk for unwanted environmental effects. Keep in mind that there is no "cure" for EAB infestation and insecticide treatments will be needed every one to three years, depending on the chemical used. Hire a certified arborist with a pesticide applicator's license to perform these treatments.
- Do not remove or treat ash trees in the public right-of-way near the street (boulevard trees), as these may be managed by the city in some areas. Woodbury Heights, Park Hills, and Royal Oaks are the neighborhoods where boulevard trees are most likely city trees. Call the Public Works Department at 651-714-3720 if you have questions.
- What is the Rainbow Treecare discount treatment program?
The City of Woodbury has partnered with Rainbow Treecare to offer residents a new discount program for preventative treatment of their ash trees against emerald ash borer (EAB).
- What are the advantages of treatment?
The entire community benefits from a mature tree canopy. An average ash tree in Woodbury will keep pollution from rivers and lakes, reduce CO2 in the atmosphere by 600 or more pounds every year, and produce the cooling effect of 10 room-size air conditioners operating 20 hours per day. Treating an ash tree for 20 years is more cost-effective than removal and replacement.
- How do I know if my trees qualify?
Rainbow Treecare will inspect the tree(s) at no cost to determine if treatment is the best option. The tree must be in good condition, showing no more than 30% of canopy decline if infested, at least 10 inches in diameter, and is not competing with other trees or infrastructure.
- I'm interested in learning more about the discount program.
If you're interested in learning more about the discount program or would like to schedule a tree inspection with Rainbow Treecare, call 952-767-6920 or visit the Rainbow Tree Care website.
- Why is the city removing ash trees in parks and public property when treatment options are available?
Not all ash trees can be treated. Also, it would be too costly to treat thousands of ash trees on city property. Treatment is more affordable for residents with one or two ash trees on their property. The city is replacing ash trees it removes with a variety of species.