In the coming months, the Tree Board and city arborist will be sharing informati on with you from the survey of trees in the front and visible side lawns of St. Regis Park. Three obvious statistics stand out, and this month we will focus on the 3rd: 1) At least 90 homes—almost 1/6– in St. Regis do not have even one significantly-sized tree in the front or visible side lawn. 2) The city is short about 500 trees of the ideal for a tree canopy (again front and sides); and 3) There are 40 ash trees in the city, ranging from 4.9 inches to 51.7 inches in diameter. Sadly all 40 are all in danger of being lost to the Emerald Ash Borer. Here’s why:
The Emerald Ash Borer (EAB) was discovered in the United States in 2002, but had probably been around for 10-12 years before that, most likely hitchhiking in wood packing materials imported from Asia via the Great Lakes. Populations of EAB began spreading quickly; they have now been confirmed in 22 states and 2 two Canadian provinces. Emerald Ash Borers have killed billions of Ash trees along the way. EAB was found in Kentucky in 2009; it is estimated that 10-17% of Kentucky’s trees are ash trees, so the Commonwealth could be looking at the loss of millions of ash trees over the next 5-10 years. Even worse, another beautiful tree, the White Fringe Tree, was recently found to be a host for the EAB, leading to the concern that the pest may start attacking other species.
To understand the destructive nature of this ti ny pest, it helps to have some knowledge of its life cycle. The adult EAB is a small metallic green colored beetle, about ½ inch long and 1/8 of an inch wide. The adult beetles will start to emerge in Kentucky in mid-May through June (depending on the weather and location). Adults feed on the leaves of the ash tree for about two weeks and then the females will start to lay eggs in the cracks of the ash tree bark. One female can lay as many as 90 eggs. The eggs hatch and the larvae eat their way into the tree tissue just under the bark. The larvae will spend a year eating and growing to an inch or so long before emerging as adults through a characteristic D-shaped hole in the bark to start the life cycle all over again. One larvae only occupies a small gallery under the bark, but hundreds of galleries can kill a tree.
The galleries that the EAB larvae excavate disrupt the movement of water and nutrients in the tree during the summer months. Foliage wilts and the canopy of the tree begins to thin as the branches die. In heavily infested trees, the canopy loss might be 30-50% aft er two years and trees will oft en die aft er 3-4 years. Trees that are stressed from lack of water or other insect or disease problems will be more susceptible to damage, but even trees that are otherwise healthy will eventually succumb to peak EAB populations if untreated.
There are some St. Regis Park residents who have been proactive and have started treati ng their ash trees to protect them from EAB damage. There are probably some trees in the city that have declined enough that treatments would not be warranted, but some that might benefit from treatment. There are a number of different insecticides and formulations that are on the market now for EAB treatment. A professional arborist can provide an evaluation of the tree’s current condition, treatment options and pricing to determine the best method for managing EAB. The cost of removal and replacement should also be considered when determining the value of trying to protect existing trees.
If you have an ash tree in your yard-front, side or back-keep it as stress free as possible by watering during dry periods and consider planti ng a new tree now to replace eventual losses.
Next month: 500 (New Trees) in Five Years!