Is It the End of the Ash Tree?
Writer / Janelle Morrison
Many Hoosiers are already aware of the exotic beetle and the ecological catastrophe that the nonnative forest insect is creating throughout the U.S., Indiana and in Zionsville. What many may not know is that the EAB has become the “most destructive forest insect to invade the U.S.” according to American Forests, a forest advocacy organization based out of Washington, D.C. Local residents may have noticed the infested ash trees or areas in which the ash trees have been cut down and wondered what is causing the damage and what is being done by local experts.
The EAB population has been confirmed in more than 18 states and recently as far south as Texas. EABs have destroyed tens of millions of ash trees in the U.S. and have been confirmed by the Indiana Department of Natural Resources (DNR) in over 95% of the Hoosier State.
The EABs were first discovered in the U.S. in southeastern Michigan in 2002. It is thought that the EABs probably arrived on solid wood packing material carried in cargo ships or airplanes originating in Asia. Indiana reported its first finding in 2004. The adult beetles feed on the ash foliage and cause little damage to the trees. However the larvae feed on the inner layer just beneath the bark of the ash trees, which essentially starves the trees of water and nutrients.
The infestation of the EABs has caused regulatory agencies such as the USDA and DNR to enforce quarantines to prevent infested ash trees, logs, or firewood from moving out of infested areas. The damage created by these beetles has cost property owners, nurseries, the forest products industry and municipalities hundreds of millions of dollars.
The Zionsville Parks and Recreation department has been hard at work identifying and mitigating the damage to the ash trees located in the parks, along trails and other properties managed by the town.
The Zionsville Parks Department Director, Matt Mickey, discussed what he and his team have been doing to treat, remove and replace the damaged trees.
“The EABs especially like the Green Ash, an ornamental ash, that was heavily planted in the 70s, 80s, and 90s,” Dickey explained. “They also like our native ashes, the White and Blue Ash which are the ones that people will see more of in parks and wooded areas. One of our parks became infested a few years ago and 14 ornamental ash trees, planted near the parking area, were all damaged. It used to be a common practice to plant one type of tree, especially when it was proven to do well in a particular area. Nowadays, we need to always think about diversification when planting trees, even in our own yards.”
The department is actively treating ash trees that have been detected in the early stage of infestation with an injectable pesticide that lasts two years. Each treatment is approximately $2,500 per tree.
Another method, soil injection, will last one year. While treatments for EAB infestation are greatly effective, the treatments must continue or else the EABs will return to the ash tree. While the ash trees are being treated, Dickey and his team are planting new and more diverse trees. Eventually, the new and diverse trees will grow and fill the gap when the ash trees succumb to the culprit beetle and are either topped or dropped. They will “top” or cut the trees and leave the trunks for the woodpeckers and other woodland inhabitants to feed from. The ash trees that are more advanced and pose a threat to pedestrians and/or structures are cut down by the department. Sadly, several ash trees throughout town have been identified as infested, including several of the beautiful ornamental ash trees planted throughout Zionsville.
According to Dickey, “We’ve been working on this for some time but it has reached a tipping point in the EAB population. It has been an issue in eastern Hamilton County in the last few years and has worked its way throughout Boone County. We took a professional certified forester around who provided a detailed assessment. Along the Rail Trail, alone, there are 85 trees that are recommended that come down over time. We are practicing dropping (taking down) the infested ash trees that are closest to the trails and structures.”
Residents who have ash trees in their yards, particularly the ornamental Green Ash, should keep an eye out for increased woodpecker activity in their neighborhoods. The telltale “D”-shaped holes in the bark or serpentine galleries in the bark indicate EAB activity. Bark splitting, canopy dieback and epicormic shoots (new shoots growing at the base and along the trunk) also indicate EAB activity.
“If someone suspects that their ash tree is infested and has seen any of the signs on their tree, they can contact DNR or any tree services that are in the area for an identification,” Dickey offered. “Once confirmed, the owner can decide the proper treatment for their tree(s).”
If you would like more information on how to identify the Emerald Ash Borer and the treatments that are available, contact the Indiana Department of Natural Resources at www.in.gov/dnr