Me and my girl were on the trail about a mile north of Winding Stair Gap heading NOBO. We pulled over on the side of the trail to stop for a minute. It was really still and quiet and no wind was blowing. All of a sudden about 30 yards or so down to our left, a couple of broomstick to wrist sized trees started to shake violently. This lasted for about 4 seconds then stopped. No noise, no movement. We froze with our eyes on the trees that had been shaking.
Nothing fell from the trees, nothing scurried away or flew away after the trees stopped shaking. When we stopped there was no sounds or anything then all of a sudden those trees started being forcefully shaken back and forth. Again there was no wind or anyone else around and there was no way it could have been something that fell from the tree.
We froze and watched and listened for about 2-3 minutes before feeling like it was time for us to leave the area. We've gone over several scenarios but we cant figure out what could cause that to happen. We came across several day hikers who have been hiking in this area for years and described our experience. No one could come up with a plausible answer. Any ideas?