Emerald ash borer (EAB) is an invasive insect that has made its way through much of southeastern Minnesota, including the park here at Ney, and continues to spread across the state, killing as many ash trees as it can along the way. These invasive insects lay their eggs directly into the bark grooves of ash trees, so when the eggs hatch, the larvae immediately make their way under the bark to begin feeding. Emerald ash borers feed on the inner layer of the bark that allows the tree to transport water and nutrients, so when this cycle is disrupted, the tree begins to die. In their larval stage, EAB look like flat, white worms, growing to around 1 inch long. As an adult, these beetles can be identified by their iridescent green body and purple abdomen under the wings, growing to only about ½ inch long.
One of the easiest ways to identify if an ash tree has been infested with the borer is by blonding on the bark. As the insect makes its way through the tree, the tree will begin to lose the outer layer of its bark, making it look like the bark is “blonding” or becoming lighter in color. If you look up close to the tree, however, you will be able to see that the bark of the tree is actually falling off. In some cases, when the tree has been infested with EAB for a long time or has died already, there will be no bark left along the trunk and branches. In this case, it can be easy to see another common sign of EAB infestation. Under the bark of an infested ash tree, you can often see the tunnels that the larvae feed their way through. These tunnels look like S-shaped galleries winding through the wood. When the bark is still intact, EAB infestation can also be identified by D-shaped exit holes in the bark, where the adult beetles emerge from.
As the emerald ash borer makes its way through Ney’s park, more and more of our ash trees are dying and showing signs of infestation. To manage the spread of this invasive species, we have come up with a plan to identify all the infested ash trees along the trails and mark them for removal. Our removal process of these trees began last weekend, as a group of volunteers came out with their saws and began felling some of the dead ashes along the trails that could be in danger of falling across the path or could potentially become a safety threat to visitors. Though it’s never fun to see sick or dying trees get removed, the ash trees that are getting cut down in our park are still serving a beneficial purpose! Some trees will be chopped into firewood for our future use, and many others will be left along the trails and in the forests to serve as habitat space for other wildlife within the park.
There is still a lot of work to be done to manage the ash tree population at Ney, but we are always grateful for the work that volunteers help us with as we continue to implement management strategies to best serve the environment in our park!