I have noticed a few large Green Ash that seem to be hanging on and still look healthy in my area. I talked with a Forestry Professor from Yale who said they are finding some that they call lingering ash. Some kind of genetic resiatance. Some good articles out there if you google more on it.
Lingering Ash (EAB Resistance): In North America, a small percentage of ash trees have survived EAB infestations. These "lingering ash" suggest a genetic basis for resisting the beetle, allowing for efforts to breed a new generation of resistant trees.