Status of the Ash Trees
Have you noticed all the ash tree seedlings popping up everywhere? Maybe not. No doubt you’ve seen all the dead ash trees that have been dying and falling for nearly 20 years. Yes, the emerald ash borer was first discovered in Canton, Michigan in 2002. Well, the proliferation of seedlings doesn’t mean the ash trees are coming back. Oh the seedlings maybe, but the bug prefers older trees so these seedlings will simply grow to a suitable size for the bug to enter and kill them. The seeding of injured ash is no mystery. Plants will instinctively attempt to reproduce when they are injured or dying. I’ve had folks tell me “my plant looks bad but it’s flowering!”. Flowering is a reproductive process which can indicate that the plant is sick or dying.
It’s interesting how the states that are just getting hit by the borer (Colorado, Carolinas) have published articles talking about the “coming disaster”. We could have told them 15 years ago about the problem but I guess it’s not really a problem if it’s not in “your neighborhood”. We have found that there is a cold temperature limit to the bug. The northern tier states don’t have the problem since they commonly get temperatures down to minus 25-30 F. Also, some areas of the country have fewer ash trees so it’s not such a big issue. However, the emerald ash borer also attacks the “ash relatives” such as lilac, Japanese tree lilac, and white fringetree. We have yet to see such wholesale destruction in those species so keep your fingers crossed that it doesn’t happen!
You might occasionally see a large healthy ash tree. These are “lingering or survivor ash” which amount to about 1% of the population. Scientists are looking at these trees to develop a resistant variety. But breeding trees is a longgggg term process, as you can imagine. It will be decades before such a tree can be developed and grow to provide us shade. If you have a “survivor”, don’t trust that it will never be attacked. Even after most of the ash are gone, the bugs will persist in smaller numbers until all these seedlings grow large enough to fall victim to the bug. There are a few insecticides that can save your tree. There are a couple of homeowner products with the active ingredients “imidacloprid” or “dinotefuran”. You can simply mix these products in a bucket and pour it on the ground around the tree in early spring each year. It is taken up by the roots and distributed throughout the branches. However, the best defense is “Tree-age” (pronounced triage). This is a restricted-use chemical that needs to be applied by a licensed tree professional. This product is injected into the trunk, spreads up the tree, and is effective for up to 3 years.
If you have large dead ash trees it is important that you have them cut down as soon as possible. Dead ash trees are very brittle and dangerous as large branches fall to the ground.
This whole issue of dying tree species is very disturbing but it has happened before. We used to have huge chestnut trees across this country which are now gone. It has been said that a squirrel could have traveled coast to coast in chestnut trees. American Elm was a classic large spreading tree shading the streets of towns across our country before the 1940s. Now we are also seeing the decline of Austrian Pine and Colorado spruce. Blue spruce is probably the most popular ornamental tree. The older trees, typically overcrowded with poor air circulation, are dying to a fungal disease. But don’t let this discourage you from planting trees! Trees are essential! We simply need to be aware of all the various species available for our Central Ohio area and plant more diversity.
By the way…………summer drought season has already started so get out the hose and soak your trees at least once every 2 weeks.
Be safe and enjoy the summer!