BOONE, N.C. — Timothy Silver served as a professor at Appalachian State University for 30 years. During that time he developed an interest in Mt. Mitchell. The billion-year-old peak is the highest in the Appalachians. 

"I was interested in unraveling that story," Silver said.

The story of Mt. Mitchell includes the mountain's namesake: Elijah Mitchell. The mountain was named for him after he fell and died while measuring it. Silver first visited the mountains in the 1990's and wrote a book after researching the area. 

Silver surveyed the view and pointed to areas that were previously logged, changing the landscape. 

There's still controversy about what caused damage to the area. It could be one thing or a combination of many. 

"In the 1950's, they discovered this really tiny exotic insect here called the balsam woolly adelgid, which is a bug," Silver said.

The balsam woolly adelgid is a boring bug that infested the fraser firs, which are native to the peak. That infestation didn't explain the damage to the other trees, like the dead and dying red spruce that bugs did not bother. People then began speculating the cause could be acid rain. 

"Air pollution, air pollutants caught in the fog and clouds," Silver said.

There is a third possible culprit — logging that was done years ago. Silver says its unclear exactly what happened. 

"You can't put a bubble over the mountain, you can't measure just air pollution or just the adelgid or just the effects of logging or just climate change, there's a long environmental history here of things," Silver said. 

Large sections of the forest are still dead, but new trees have been planted and are beginning to grow back underneath. Silver says those trees are forming a natural resistance to the bug and are able to thrive. He is hopeful to see it going in the right direction.