Here in Maine, in my lifetime alone (34 years) we have been hit with the Spruce Budworm epidemic, a hackmatack bark beetle infestation, Dutch Elm Disease and now are going back to a Hackmatack Beetle infestation again. Its painful to see the trees be lost, but it's actually just part of mother nature and forests.
I've been cutting 12 acres of trees we planted in 1994 and 1996 because the hack we planted has been hit hard by the beetle. Its one of the reasons I chose to get into sheep. The trees were dying and I needed to make 12 acres productive. The Maine Forest Service pathologist said my trees were being hit at 3-4 trees per acre per year. He was way off. I have only cut 2 acres so far and yet the infestation is far worse then that.
The Spruce Budworm was far worse and hit northern Maine really hard. Something like 11 million acres affected and killed them off. It was one of the reasons thousands upon thousands of acres of trees were clearcut in the 1980's. In the 1990's some environmentalists tried to ban clearcutting in the state, but they already missed the boat. It was not so much a forestry tactic as it was a recovery effort. Of course in 40 years when those replanted tree mature, it will mean thousands of acres of same-aged trees hitting maturity.
Overall I don't get to concerned about forest diseases. Even with quite a few acres in trees, it runs it course, then changes. In between keeping up with it is just part of being a responsible landowner. Adapt and keep going...
I have no intention of traveling from birth to the grave in a manicured and well preserved body; but rather I will skid in sideways, totally beat up, completely worn out, utterly exhausted and jump off my tractor and loudly yell, "Wow, this is what it took to feed a nation!"