You may have heard of emerald ash borer, as this invasive pest has recently made its way into Maine. This is big news, as the insect is capable of killing almost all of the ash trees in Maine, which is a huge problem. If you don’t know much about what this means or what you might do, this post is offered as a starting point. First of all, it is a good idea to become aware of ash trees…those on your land and around your town. In many places in Maine, ash trees make up a significant component of our forests. In towns, along streets, in parks and schoolyards, ash is a popular tree that has been planted for a long time. How do you identify an ash tree? There are several species of ash in Maine, but you don’t really need to be able to tell them apart, as the emerald ash borer affects all kinds of ash. In general, ash trees have a leaf composed of a number of “leaflets” (which look like leaves themselves) along a stem. Ash have thick twigs, and bark with regular ridges going up and down the trunk and branches. See the picture below to see the leaves (each green stem with 5-7 leaflets along it is actually one leaf) and bark. Different species vary slightly from this basic form.
Next time you are out, try to see if you can identify ash on your property or nearby. Since it’s winter, look at the bark, and look for thick twigs gently curving upward at the ends, and coming out from branches directly opposite of one another.
In only 15-20 years since the pest arrived in North America, EAB has spread from Wisconsin and Michigan, to Missouri, to Quebec and across New England. Some states have lost nearly one hundred percent of their ash trees as the emerald ash borer has become established. If you travel through the Midwest in summer, in places you will see many trees that are bare and dead or dying, so much so that it looks like winter in places.
Can we avoid this in Maine, where the infestation is not yet widespread? Ash is an important tree for lumber, firewood and wood products. For some landowners, harvest plans for ash are part of making their forest economically productive. Our parks and streets are lined with ash trees. The seeds of ash are important food for wildlife and birds. The depressing scenario of losing all of this tends to fill our thoughts as we think that soon Maine ash will meet the fate of ash trees in many states.
The truth is that there are many reasons to hope, and to take action. Right now, in most of our towns, emerald ash borer is not established…giving us some time to respond, and to take advantage of what other states have learned. Depending on many factors, it could reach your town many years from now–or in the coming year, if somehow infested wood or trees are transported into your area. So limiting the spread of EAB is step one, which you can take right now by not moving ANY ash wood, firewood, or nursery stock – especially not from out of state. Areas of Maine are under quarantine, where movement of ash wood is prohibited, and further quarantine areas will be established.
Another important thing to do right now is to become aware of the signs of emerald ash borer… early detection of the insect is a key step in combatting the outbreak. You may be the first person to notice it in a new area if you stay alert for the signs. So its possible we could slow the spread of emerald ash borer through effort and awareness. Other methods offer hope in slowing the emerald ash borer in Maine. Scientists have developed means of slowing emerald ash borer movement through creation of trap trees and population “sinks” where the insects are lured to weakened trees and then destroyed. Insecticides have been developed that effectively protect ash trees, and so high value trees in yards or parks can be saved. Even slowing down emerald ash borer populations in Maine could save 800 million dollars, according to US Forest Service estimates.
The truth is though that eventually, many ash trees in Maine will likely succumb to the emerald ash borer eventually. But don’t panic and cut all your ash trees right away! It usually takes 5 – 10 years for a outbreak to take hold, and in some areas it may take longer for EAB damage to show up. Plus, there are strategies for managing forests with ash trees in the resources below – talk with a licensed forester or call the Maine Forest Service for additional guidance for your situation.
Will ash trees be forever lost to our forests? In fact, it is quite likely that through the efforts of scientists, landowners, towns, universities and agencies, we will be able to restore the ash tree in Maine in time. One part of the solution is using “biocontrols,” or predatory insects that will feed on the emerald ash borer. In the future, when there will be many fewer ash trees (and thus fewer emerald ash borers), such biocontrols may be an important way to keep the emerald ash borer in check. Another important strategy will likely be the effort to find the few ash trees of different species that have some inherent ability to resist the emerald ash borer, cross breed those individuals to create stronger and more consistent resistance in offspring trees, and then propagate and plant resistant trees in forest restoration efforts. This is a primary reason for leaving ash trees in place, and as trees start to die, to note any trees that seem to stay healthy in an infested area: they may be genetically resistant, and thus very important to preserve. Genetic technologies now available will likely offer further options to create resistant trees. And these technologies are developing rapidly. In the Midwest, where emerald ash borer has killed many trees, researchers are well on their way to developing methods to propagate resistant trees we can readily apply in the Northeast. We need to take the time now to learn from their work and get ready to implement these efforts here. We need to plan for how we will face emerald ash borer infestation in Maine with systematic, multi-faceted strategies. And with luck and some hard work, we’ll be able to offer our children and grandchildren forests with this strong, beautiful, important tree.
Some interesting resources to learn more:
Pictures of basic signs and symptoms of emerald ash borer infestation
Emerald Ash Borer University: a YouTube channel with lots of interesting, short videos on everything I’ve talked about here.
Emeraldashborer.info has pretty much all the information you could need on emerald ash borer in the US.
https://www.maine.gov/dacf/
