A rock ring around the pit does little to prevent ashes from spreading, so resist building one. Collect only dead or down wood and think small. Bonfires are dangerous, especially during midsummer when forests are dry. Burn the fire to ashes and douse heavily with water until dead and cold. Finally, cover the cold ashes with the soil that was originally removed from the pit.
National parks prohibit the collection of firewood, even of deadwood that has fallen to the ground.
At backcountry camping sites, the use of a fire pan is required and all ashes must be packed out. National forests may prohibit the use of ground fires during seasons of high fire danger. Keep a clean campsite Pack out your trash, recycle it whenever possible, and go the extra distance to clean up after less thoughtful visitors. No one wants to camp where someone has left trash and human waste, and creating a new campsite can stress the environment. Carry plastic bags in your vehicle and pack out all trash if garbage collection is not available.