Treating Ash Trees in the Palisades

by Ken Brooks, Volunteer Preserve Monitor & Land Steward

The Nature Conservancy is faced with calamitous circumstances regarding some trees located at its Kentucky nature preserves. For example, the Chapter staff and a handful of dedicated volunteers has been treating many of the hemlocks under attack from the woolly adelgid at the Bad Branch Nature Preserve in Eastern Kentucky at a few selected trees at the Baylor Hickman Nature Preserve in south central Kentucky. Recently a new invasive problem has been reported attacking walnut trees.

Treating Hemlock wooly adelgid at the Bad Branch Nature Preserve © TNC Staff
Treating Hemlock wooly adelgid at the Bad Branch Nature Preserve © TNC Staff

In our neck of the woods, in the Palisades, ash trees are experiencing invasion from the emerald ash borer. Since entering the United States in 2002 from East Asia, this insect has now spread to 22 states including Kentucky. Ash trees represent, by some estimates, one quarter of the trees in our big cities and are a huge percentage of the trees in Lexington. They also have a significant presence in our Palisades nature preserves where some trees are already dying. In fact, you can spot the dying canopies in these trees as you visit the preserves.

Ash Borer on Leaf © University of Kentucky
Ash Borer on Leaf © University of Kentucky

In an effort to reverse a troubling trend, our nature preserve steward, Zach Pickett and myself recently treated 10 ash trees at the Brown/Crutcher/Wallace Nature Preserve. The trees chosen are all near the Brown Trail, the three-mile loop trail that eventually goes all the way to the Kentucky River. These trees will need to be treated regularly until the borer dies off – likely once virtually all the untreated ash trees have died and there is no more food to support the population. Our goal is to have a few survivors that can then help to repopulate our nature preserve.

The trees treated vary from less than 6 inches to about 2 feet in diameter. If you hike the trail, you can possibly identify the treated trees by the large blue dot painted about chest height on the trunk. Zack also treated ten trees at the Dupree Nature Preserve, including the HUGE ash tree near a picnic table where the main trail joins the Brooks-Schwantes Trail, likely the largest ash on any of the Palisades nature preserves.

Green Ash Tree at Dupree Nature Preserve © Craig Dooley
Green Ash Tree at Dupree Nature Preserve © Craig Dooley

Without treatment, we can expect nearly all the ash trees to die. Is there any hope? Two pieces of encouraging news lead us to believe there is:

1) Blue ash trees seem a bit less vulnerable and some of these seem to be surviving.
2) New trees are sprouting where the mature ash population has been killed.

We can only hope that when the infestation has passed that new seedlings will emerge from the soil, allowing these spectacular trees to return to our Palisades.