I was going to say that it looks like white ash, but wanted to wait to see @tamaracks answer in case I was wrong. those trees are toast. you will see some leaves next year, but will be mostly bare. Cut them down before they become a hazard. I had a dead one standing in my woods for the last couple of years, it finally came down in the wind the other day.
the only way to stave off the ash borer beetle is preventative treatment before they invade. you are several years too late.