Prehistoric people in the Southwest relied on fire, not corn

It has long been thought that prehistoric villagers in the American Southwest survived on corn. But according to new research from the University of Cincinnati, even though corn was an important part of life thousands of years ago, it was not the main fare for all people in that region.

The study was led by Alan Sullivan, a professor of archeology, who argues that prehistoric people who lived near the Grand Canyon burned down the understory of forests and lived off of wild crops. Sullivan’s theory comes from years of research and excavations around the Grand Canyon where no presence of corn as a crop has been found.

“It’s been widely considered that prehistoric peoples of Arizona between A.D. 900 to 1200 were dependent on it,” said Sullivan. “But if corn is lurking out there in the Grand Canyon, it’s hiding successfully because we’ve looked all over and haven’t found it.”

The Grand Canyon is home to vast, dense forests on both the south and north rims in the Upper Basin, and this is where Sullivan and his research team have completed their excavations. The archaeological team found ancient shards of pottery but little evidence of corn.

However, the researchers did identify pollen from the clay pot remnants which date back 1,000 years and found evidence around the excavation sites that point to fires being set to burn the grassy, weedy understory of the forest.

Sullivan examined ancient tree rings and found no burn scars, which are caused by massive wildfires. If there wasn’t a buildup of underbrush and felled trees, there would be fewer major wildfires.

The research team also examined the geologic layers at the excavation sites and found that there were more edible plants available during this time, further proof that native plants were the primary foodsource for ancient people around the Grand Canyon.

The fires not only managed the underbrush but also created ideal soil conditions for ruderals, which are edible plants and quickly spring up after a fire.

These prehistoric land management practices could help foresters enlist stronger policies that drastically reduce forest fires.

Controlled burning and clearcutting are common practices by the National Parks Service and the Department of Natural Resources, but it is becoming increasingly difficult to control the fire hazards in national forests.

“These forests are unnatural. They’re alien to the planet. They have not had any major fires in them in decades,” said Sullivan. “The fuel loads have built up to the point where you get a little ignition source and the fire is catastrophic in ways that they rarely were in the past.”

Preserving forests in the face of climate change and deforestation is important for conservation, biodiversity, and reducing the risk of wildfires destroying homes in residential areas. Sullivan’s research could help present alternative strategies based off ancient cultivation practices.

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By Kay Vandette, Earth.com Staff Writer