Help Save Minnesota Trees from the Emerald Ash Borer

Invasive species are bad news. Most of us in the Land of 10,000 Lakes who spend time on the water have heard of the zebra mussel and the absolute havoc it wreaks on lake ecosystems. But another significant problem that is much less known to the general public is the emerald ash borer and its devastating impact on our ash trees.

The Minnesota Department of Natural Resources estimates that the state is home to 1 billion ash trees, which include black, green, and white ash. Black ash trees play an important role in maintaining the water table in wet forest areas and providing habitat for wildlife. Green and white ash are popular shade trees in urban areas and provide nesting opportunities for birds and squirrels. The loss of these trees would have massive negative impacts on the ecosystems of which they are a part, and large monetary impacts on urban communities which would have to deal with removal of the dead trees.

But all is not lost—there are things we can do to minimize the damage caused by this invasive species and save our ash trees! Please take a few minutes to educate yourself on this problem and the actions you can take to help protect Minnesota’s ash trees.

A size illustration for the emerald ash border. Howard Russell, Michigan State University via Wikimedia Commons

What’s the Problem?

The emerald ash borer (EAB) is an invasive beetle that feeds on ash trees during the larval stages of its growth. Female EABs lay eggs in crevices in the ash bark, and when those eggs hatch, the larvae bore into the tree and begin eating the tissues under the bark. Unfortunately, those tissues include the vascular tissue through which nutrients are transported. You can kind of think of it as the tree’s circulatory system—like your veins and arteries transport oxygen and nutrients in your blood to every part of your body, the vascular tissues within a plant transport water, sugar, and other molecules around the plant. When EABs eat the vascular tissue, it disrupts the transport of nutrients, and branches begin to die. Once too many branches have died, the whole tree dies. And this can happen fairly quickly; once a tree begins to show symptoms, it can die in as little as a year.

To learn more about the emerald ash borer, check out these resources:

• Minnesota DNR
• University of Minnesota Extension
• Andrew the Arborist

What Can I Do?

First, if you own property, check to see if there are any ash trees on your land. I think this is the biggest stumbling block to stopping the emerald ash borer: how many people can just point to a tree and say, “Yup, that’s an ash”? If you don’t know you have ash trees, you won’t know to protect them. Fortunately, identifying ash trees is fairly simple, and because the EAB is such a huge problem across the United States, there are many, many online guides that can help you.

Very simply, there are three things you can look for to identify ash trees:

1. Branches that grow opposite each other
2. Compound leaves with 5 to 11 leaflets
3. Diamond-shaped ridges on the bark
   

   Left: Green ash bark with characteristic diamond-shaped ridges. Center: Compound leaves with seven leaflets. Right: Branches growing directly opposite each other.

You can also use species ID apps for help, if you need it. Brightly has compiled a list of apps.

Once you know you have an ash tree under your care, you should have it checked out by a skilled arborist to see whether it shows any signs of EAB infestation and, if so, assess the extent of any damage. Many townships in the Twin Cities area have partnerships with arborists to help deal with the EAB situation, so check your town or county’s website to find that information. My township has an agreement that included a free consultation and a discount on treatment. My ash tree does have damage from EABs, but it thankfully isn’t too extensive, and they advised treatment to try to save the tree. The treatment was a couple hundred dollars, but that is much less than the thousands it would cost to remove a dead or doomed tree. The treatment is good for about two years and then should be repeated.

If you don’t own property or you don’t have ash trees on your property, there are still things you can do to help! Share information about EABs to friends, family, and neighbors to help increase awareness and thus action, and do not move wood from location to location. The areas of Minnesota with known EAB infestations are under a quarantine to try to limit the spread of the insect—EAB eggs and larvae hitch a ride when ash wood is moved, causing infestations in new areas.

The natural resources in our state benefit us all in many ways and are a point of pride for Minnesotans. It is incumbent upon us to be good stewards of the land and environment not only for future generations but for the plants and animals with which we share the world. Please consider taking action to help save our ash trees.