So the cycle of nature goes on. Once the hemlocks are gone in that area, those pests will have finished off their food supply and they will die off. Hemlocks will return via bird poop and wind borne seeds.

The idea that we can avert all natural occurrences is idiotic. Those dead trees will at some point fall over, rot and become part of the food chain for the understory. And by their falling over, they'll knock down other trees opening up the ground to low growing plants which the fauna needs to live. Dense forests harbor no life except pilated woodpeckers and mice. Animals live on the edge where trees and meadows meet.

Eastern forests are mostly deciduous, which makes them mostly fire proof. The one thing we can do is stop that stupid reg that the enviro-nazis had the Forest Service place: Preventing people from using deadwood for making campfires. All that detritus left is the fuel that makes those western fires so fast burning and hard to put out.

"Those dead trees will at some point fall over, rot and become part of the food chain for the understory."

Yep.

The perhaps more problematic invasion is the balsam wooly adelgid. This one is going after the spruce-fir trees that tend to appear only at the highest elevations in the GSMNP. These stands are largely coniferous and much more susceptible to fire.

Sadly even if the Park Service were willing to use pesticides it would still be a losing battle as they could never eradicate the insects outside the park and so would at best be caught in a slow motion defeat.

Given that, the best solution may be to accelerate the process that you note - rather than leaving the dead stands upright, at least drop them in place in order to reduce the risk of catastrophic wildfire and also to hasten the decay process.

The park you see today is not the park that people will see in fifty or seventy five years. Of course the same could have been said seventy five years ago - when the chestnut blight was having it's way with the park.

My husband and I hiked a number of trails of this majestic area. The saddest sight was at the top of Clingman's Dome, where huge swaths of these giant dead toothpicks stood poking up everywhere. My husband's job being in the fire service, we immediately commented to one another, "Wow! look at all those torches just waiting to be lit up." Maybe that's the NPS' ultimate solution.

Trees are attacked by insects when they are weak. Strong trees resist insect attacks. Generally. On Mt. Mitchell there was a prolonged drought. Not a total drought, just a lessening of the annual rainfall. Perfectly normal weather pattern. The Balsam Firs suffered. They live at high altitude on thin soil above solid rock. Many died, bugs came in, people blamed the bugs and fungus and everything else. Oooooooooooops. The area has cycled back to wetter and the trees are once again very happy.

Then there was the problem with the locust trees. It appears that we are currently in the middle of that "crisis".

Then the hemlocks. We are at the beginning of this "crisis". Oh my.

In a hundred years the park will look very much like it did during the previous cycle that was similar to the one a hundred years from now. Just like the park currently looks a lot like it did during the last cycle when the hemlocks were stressed. Around, around we go.

Ignoring the effects of invasive species not present prior to the early 1900s (both adelgids, chestnut blight, emerald ash borer, etc.) will not make them go away.

Both they, and their effects are here to stay.