Wolves returned to Yellowstone; 30 years later, young aspens followed

 Thirty years after wolves were reintroduced to Yellowstone National Park, researchers say aspen trees are showing stronger signs of recovery. The findings add to growing evidence that restoring a top predator can reshape an entire ecosystem. Thirty years after wolves were reintroduced to Yellowstone National Park, researchers say aspen trees are showing stronger signs of recovery. The findings add to growing evidence that restoring a top predator can reshape an entire ecosystem.