As far as I know not a single living Ash tree is left in this region, and most have been dead for several years now. I started telling everyone to take the trees down right away, the answer was always, they still look good it's a nice shade tree. Well now they had to call in a tree company to come in and take the trees out the expensive way, as I wasn't going to touch the rotten messes, can't even use them for firewood. So yes the sooner you can get to then the better.Fortunately it hasn't got that bad here YET. Very rarely do I come across one that's beetle killed in fact. I looked at a tract a few months ago that's got some of the best ash Ive ever seen on it and the idiot that owns it still hasn't decided to cut! His wife wont let him cut it! I told him to bring her up there, show her one of the bigger ones and tell her to take 700 bucks out of her purse and burn it because that's what she is going to lose when that one tree dies. Theres probably 50 or more trees like that on just one little hillside too.
Here's one that came down on it's own just the other night, took out the power for over 100 homes.