Fire, not corn was key to prehistoric survival in the arid Southwest USA
Sullivan has pieced together clues firsthand and from scientific analysis to make a persuasive argument that people used fire to promote the growth of edible leaves, seeds and nuts of plants such as amaranth and chenopodium, wild relatives of quinoa. These plants are called "ruderals," which are the first to grow in a forest disturbed by fire or clear-cutting.
Fanning the Flames of the Theory
Sullivan also studied the geologic layers at these sites. Like a time capsule, the stratigraphic analysis captured the periods before and after people lived there. He found higher concentrations of wild edible plants in the period when people lived there. And when people abandoned the sites, the area they left behind saw fewer of these plants.
Indeed, succession is the way nature has always worked and always will work. Fire is the disturbance and the fire resistant trees are the ones that survive, the soil is laid bare and the first successional plants get to sprout.
This same event is how low bush blueberries and cranberries replenish. Not something that has not been known for decades It was written about back in 1924.
In the Sonoran desert (which is very much not a fire-adapted ecosystem) the cheno-ams provide a flush of greens right after the monsoon rains arrive. No burning required...in fact, prior to the introduction of Old World grasses to the region, there really wasn't a way to burn the desert. The higher elevation grasslands burned every summer at the outset of the monsoon thanks to dry thunderstorms. Native peoples in the lower deserts harvested cactus fruit and mesquite beans in the hottest part of the summer, and then when the rains arrived they got the burst of amaranth and lambs quarters to keep everyone fed until their floodwater crops were coming along.
The Spanish padres who arrived in the Pimeria Alta in the 17th century were horrified to see people happily eating the greens on all fours, grazing like sheep, and thought it was evidence of how far they had fallen from grace. The reality is more like why would you waste time and effort hand-picking your salad when it's all laid out in front of you? I used to love seeing the cheno-am carpet on the fallow beds in my garden in the middle of summer, and tried the traditional eating style myself.