By: Ron Gumz, Certified Arborist MN-0324A
Wouldn’t it be nice to have a time machine that could take you into the future to get a glimpse of what may be coming our way? People often say of tragedies that if they could have known what was coming, they likely would have handled the events differently. Well, we are on the cusp of a disaster with our ash tree population due to emerald ash borer (EAB). Though we do not have a time machine to bring us news from the future, we do have the experience from other areas of the country that provides a very accurate forecast for our area.
Many of you may be aware of EAB at this point and the implications of this insect. The media and others have done a good job of raising our awareness. In the summer of 2008, emerald ash borer was positively identified in Wisconsin for the first time. By the time the insect was noticed in Newburg, the consensus was that it had been in the area for several years already based on the extent of the ash tree damage. Now fast forward to the summer of 2012. Several new discoveries of emerald ash borer were discovered throughout the metro Milwaukee area during the year.
Dr. Dan Herms of Ohio State University and others have done studies on ash mortality as EAB moved through parts of Michigan and Ohio. His Ash Mortality Curve (see graph) was partially developed using dendrochronology which is the study of the annual growth rings in trees, especially as a way of dating pest infestations or determining past climatic conditions. This data shows a steep incline of the death rate of ash trees as the borer overwhelms an area. Ultimately, the graph tells us that after EAB has been in an area for a specific time period, the number of dead ash trees climbs exponentially.
The Milwaukee area is likely at a point where Michigan was in 2002 to 2004, just at the point where the number of dead ash trees start to spike. Some surrounding communities like West Bend, Oak Creek, and Franklin are already ahead of the Milwaukee time frame. At this point, the steep climb in ash mortality is close at hand. For better or for worse, the demise of ash trees in other areas has given us a glimpse into the future that does not require a time machine. We will be seeing many untreated ash trees dying from EAB in the next few years.
If you have not prepared already, the time to deal with emerald ash borer is upon us. Many people have taken steps to protect the ash trees that are important to them. Planting new, diverse species of trees is also an option when considering your possibilities. If you have been on the fence about what you would like to do about your ash trees, please get in touch with your Wachtel Tree Science Certified Arborist to develop an action plan.