Forest Service needs your help in ash borer battle

Steve PollickCould it be that North America’s besieged family of ash trees, under a deadly sentence from the infamous, destructive emerald ash borer, may yet survive and rise like the mythical phoenix from the ashes?

Some researchers with the U.S. Forest Service think so and they have begun an intensive search – and are seeking your help – in locating what are known as survivor trees at Ground Zero of the ash borer infestation, northwest Ohio and southeast Michigan.

It all began a few years ago when Kathleen Knight, a research forester with the Forest Service’s Northern Research Station office at Delaware, Ohio, was walking back to her car after inventorying ash trees in a research plot at Oak Openings Preserve Metropark in Swanton, Ohio. All of the ash trees that she had been monitoring had been killed by emerald ash borer, but just outside of her research plot, Knight was surprised to find a perfectly healthy ash tree.

The stout survivor encouraged Knight and her colleague, Jennifer Koch, a research biologist with the Northern Research Station, to investigate exactly how some ash trees are surviving the borer onslaught. Emerald ash borers are a non-native invasive insect that has killed millions of trees since it was first discovered in 2002. Dead trees litter woodlots and creek bottoms across northwest Ohio and increasingly south and east across the state.

Knight and Koch’s early work involved survivor ash trees they discovered or heard about from other scientists. But now they are seeking citizens’ help in finding survivor ash trees. The Northern Research Station launched a new an online system for reporting the location of survivor ash trees in 10 southeast Michigan counties and 7 northwest Ohio counties:  http://www.nrs.fs.fed.us/SurvivorAsh.

Visiting the survivor ash page online can help you identify the general location of a tree by entering an address, zip code, latitude and longitude, or even a place name, such as the name of a forest, park or wildlife refuge. Google Maps shows the area, and from there users can zoom in using either map view or satellite view until they can pinpoint a tree’s location and mark the spot with a digital “thumbtack.”

 “To understand the mechanisms of resistance, we need to study more than just a few survivors,” Knight said. “We need to be able to look at different species as well as genetic diversity within the same species.”

To be sure that suspected survivor trees truly are survivors, and not just ones that somehow have not yet been infected, Knight and Koch are limiting ash reporting to counties that have been hit hard by EAB. As the insect continues to spread, they expect to open the survivor ash reporting system to additional locations. Trees reported through the system should be natural ash trees rather than planted ash trees, and they should be 10 inches or more in diameter. Ash trees treated with insecticide to prevent EAB should not be reported.

As survivor ash trees and their locations are identified, Knight, Koch and Ohio State University partners will identify the most promising trees and then collect cuttings (small branches or twigs), which Koch will propagate in a greenhouse. Taking cuttings is relatively non-invasive and will not result in harm to the ash trees. When propagated trees in the lab are big enough, EAB eggs will be placed on the trunk and scientists will study how the trees respond to the insect.  

“Over the past two decades, emerald ash borer has changed forest landscapes and has been especially devastating to the ash trees in urban forests,” said Michael T. Rains, Director of the Northern Research Station and the Forest Products Laboratory. “The Forest Service is helping cities and states prepare for and recover from EAB invasion with research on the insect, ash trees’ resistance to EAB, and management strategies.”  

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