burned forests are also common. Within this generalized outline, a variety of Arizona Mountains forest ecosystems are found in the wilderness, mostly characteristic of a transition zone between the Chihuahuan Desert and flora typical of the Rocky Mountains. The wilderness includes mesquite, Apache pine and is the northernmost home of the Chihuahua pine. Gila contains one of the world's largest and healthiest ponderosa pine forests. Arizona sycamore, walnut, maple, ash, cottonwood, alder and willow trees are found along rivers and in canyons. Gila is home of predators such as the bobcat and cougar. Mule deer, white-tailed deer and pronghorn are all found in the wilderness. Other mammals include the black bear, collared peccary, gray fox and white-nosed coati. The critically endangered Mexican wolf was reintroduced to the wilderness in 1988 with eleven captive-raised individuals. Most died or were killed and more were released the following year. As of 2006, four packs have established themselves within Gila. Because of conflicts with livestock owners, the federal predator control program has killed or removed several animals. Bighorn sheep were common throughout the region until about 1900 when they became locally extinct through hunting. Rocky Mountain bighorn sheep were reintroduced to the Gila Wilderness after 1958 from a growing herd of Canadian releases in the Sandia Mountains. Elk were reintroduced by the New Mexico Department of Game and Fish in 1954 with sixteen animals from Yellowstone National Park. Game birds include wild turkey and dusky grouse; birds of prey include common black hawk, zone-tailed hawk, goshawk, osprey and bald eagle; American dippers are found in mountain streams. The wilderness is home to the largest population of near threatened spotted owls, which prefer Douglas-fir or white fir stands and can be found in ponderosa pine forests with a well-developed Gambel oak understory. Reptiles such as the Arizona coral snake and Gila monster are rarely present; common snakes include the black-tailed rattlesnake, rock rattlesnake, and Sonora mountain kingsnake. Brown trout, rainbow trout, catfish and bass are found in rivers and streams. The threatened Gila trout is present in Iron, McKenna and Spruce Creeks. It prefers sufficiently deep water, such as American beaver ponds, which provide hiding places and can withstand both floods and drought. Recreation The U.S. Forest Service describes the climate of the Wilderness area as "four gentle seasons." The lower elevations below are accessible all year with heavy winter snow uncommon. Elevation moderates the