Before Columbus, a vast continuous mature hardwood forest stretched from Canada to the Gulf coast and changed little over the centuries. It was home to many creatures, including passenger pigeons that once darkened the skies by the millions, ivory-billed woodpeckers that depended on large stands of mature trees, woodland bison, Carolina parakeets, wolves, and mountain lions, though several of these later disappeared or became probably extinct. For eastern Indians, the white-tailed deer was a mainstay, providing meat, buckskin, antlers, and bones for tools, while stone, wood, clay, and plants supplied weapons, utensils, canoes, huts, pottery, body paint, food, basket materials, and medicines. Settlers who followed the explorers cleared the forest and put the land to the plow, and farming later deteriorated as repeated planting of corn, cotton, and tobacco depleted the soil and erosion ruined many farms. As fields were abandoned, nature began reclaiming them, and in certain areas along the Trace the forest returned through plant succession, from sassafras and sweetgum to pines, then to oaks, black gums, and finally the hardwoods that again dominate the eastern forest.