Not to be too controversial i'll like to toss in a new aspect to this Ash tree death. I have been told by an old time forester that it is not the beetle killing the trees. But it is a fungi infecting some of the trees. Importantly not all of them. At least here in Europe they try to save the still healthy trees and use them for future seed suplyers. The beetle is a sign that the tree is ill as the healthy trees don't get infected with beetles. I remember that from my early years in my dads woodpile. In the hot summers I could hear the beetles chewing and see the dust from theit poo. The beetle have been there longbefore the Ash tree death was invented. Now they just seem to have an endless foodsuply.
And this maybe have to be moved to another forum. And so ....!
Motorsen