By studying fire scars in ancient wood, many scientists have become convinced that Indigenous people transformed North America long before European colonizers arrived. M.R. O’Connor spends time with dendrochronologists, who study tree rings, and other experts to understand what they’re learning:

Anthropologist Omer Stewart, who began documenting Native American burning practices in the nineteen-thirties . . . found that Indigenous communities burned prairies to attract bison to fresh grass and to maintain oak “orchards” where food could be gathered. He became convinced that Native Americans had reshaped the geography, and in some cases the climate, of North American ecosystems. Their impact “was profound, in terms of the amount of land converted to agriculture, the species they hunted and fished, and most particularluthe way they shaped their world through the use of fire,” the naturalist Scott Weidensaul wrote, in his 2012 book The First Frontier. Weidensaul argued that early America “was fruitful beyond modern recognition, it was riotous in its natural wealth, but it was not wilderness.” The dendrochronologist Evan Larson, at the University of Wisconsin-Platteville, made a similar claim: settlers encountered rich landscapes because Native Americans were tending them. “Whenever you’re talking about fire, you’re engaging with a central narrative around this untamed frontier and wilderness,” Larson told me. “In fact, that’s never been true. The early success of pioneers was already benefitting from the labor of somebody else.”