Ash trees have been an important part of the American landscape for thousands of years – lining streets, shading backyards, and welcoming patrons to businesses from coast to coast. Known as the Fraxinus Americana, the white ash (or American ash) is the species commonly found and native to much of North America.
But a highly invasive pest known as the Emerald Ash Borer (EAB) threatens the extinction of a tree as familiar to America as apple pie.
Studies reveal that EAB first infected ash trees in Detroit suburbs in the early 1990s, though it wasn’t until 2002 that researchers and foresters officially identified it. Now, 35 states in the U.S. and five Canadian provinces are battling EAB from destroying every ash tree in its path.
It is believed that the first infestation of EAB was caused by the transportation of pallets from overseas which contained the beetle. Since then, many surmise that infected firewood and lumber have been the culprit for spreading EAB to many states and provinces in North America. Unfortunately, it’s often been difficult to control the spread when infested trees are improperly removed and disposed of by homeowners and municipalities.
How do you know if you have an ash tree on your property?
Trees form foliage buds known as opposite and alternate. In other words, the buds (leaves) are either directly across from one another (opposite) or found in different positions along the branch (alternate). In ash trees, the foliage buds are opposite. Ash trees have compound leaves with 5-11 leaflets, “which are attached to the middle vein and have their own stalks. Envision a bunch of single leaves, all attached to the main stem, called a rachis, which in turn is attached to a twig.”
What are the visible signs of EAB infestation?
It’s important to know that the adult beetle does little to no damage to an ash tree. Instead, it’s EAB’s larvae. They bore their way through the cellular makeup of the ash tree, which eventually cuts off the supply of water and nutrients leading to its demise. Because of this, it can be difficult to identify infestation until it’s too late.
Some things to look out for to determine if your ash tree may be infested with EAB include dieback of the tree canopy, new branch growth in unusual locations, splitting of the tree bark, and an increased presence of woodpecker feeding.
How effective is the treatment for EAB?
Typically, ash trees that are treated early while they’re still strong often have the highest success rate. While a tree may survive a severe EAB infestation if treated, it’s improbable.
Treatment for EAB is considered systemic, which means that the insecticide is either injected directly into the tree trunk for immediate absorption or into the soil, where the root system absorbs it. Either way, the treatment enters the vascular walls of the tree where EAB feeds.
What to expect from an EAB treatment?
If an ash tree is left untreated, especially in areas where EAB has been detected, the tree will almost certainly die. While the success rate for treatment remains high, if the infestation is already present, ash trees could have a sparse appearance with accumulating dead branches. This doesn’t mean that the treatment is not working, but rather that the tree’s health is slightly compromised in terms of strength and vigor. Once the mortality curve of EAB subsides, the tree should return to its normal state. For some recently treated, healthy trees without prior infestations, tree growth can accelerate, causing leaves to be abundant that season.
How long do you have to treat your ash tree from EAB?
When EAB infestations are high in your area, it’s wise to treat them yearly for the best efficacy. Under normal conditions, the treatment has been proven effective when performed every two years. As for how long you will need to treat ash trees on your property, that answer is more complicated. Once all trees have been treated or sadly destroyed in any one geographic location, EAB will be without its host and should become extinct. However, EAB has been a continual problem since 2002 and shows no signs of slowing down.
What are suitable trees to plant to replace an ash tree?
The sad reality is that many ash trees will be lost, and due to the destructive severity of EAB, many are unwilling to replant the same species if replacements are necessary. The following are suitable replacements with similar qualities to ash trees. Big tooth maple, state street maple, pink sensation boxelder, Caddo sugar maple, western catalpa, honeylocust, Kentucky coffee tree, Texas red oak, bur oak, chinkapin oak, English oak, Shumard oak, London planetree, chokecherry, linden, hackberry.
For more information on EAB treatment options, give your local SavATree branch a call today!