On a warm July morning, roughly two dozen volunteers gathered at a ranch outside Cody, Wyoming, carrying wire cutters, gloves, buckets, and bottles of water. The goal was to take down several miles of barbed wire that had not been used to fence livestock for many years—and were now a useless and even dangerous blemish on the landscape.

West of Cody, on the road to Yellowstone National Park, the North Fork of the Shoshone River winds through the Absaroka Mountains, a landscape of extinct volcanoes that once towered thousands of feet higher. Strange formations of eroded volcanic rock, known as hoodoos, cap the hillsides. If you’re lucky, you might see a flock of bighorn sheep scampering beneath these ancient