Here, a legal mountain biker goes airborne down a trail. Mountain bikers have pushed to overturn the prohibition on riding in federal wilderness and they've blazed "user-created" trails in wilderness study areas in national forests and BLM lands. Illegal trails represent a chronic problem in Greater Yellowstone and throughout the West. On the internet, mountain bikers have vowed to carve out trails whether it's legal or not. Given the lax record of enforcement by the Forest Service and BLM in putting a stop to outlaw trails, can the Custer-Gallatin be trusted to regulate mountain biking use in areas like the Porcupine and Buffalo Horn drainages in the Gallatins? Photo courtesy BLM/Bob Wick.