Science Daily —
If you were to visit the Great Basin and Colorado Plateau a thousand years ago, you’d find conditions remarkably familiar to the present. The climate was warm, but drier than today. There were large populations of Indigenous people known as the Fremont, a who hunted and grew crops in the area. With similar climate and moderate human activity, you might expect to see the types of wildfires that are now common to the American West: infrequent, gigantic and devastating. But you’d be wrong.
In a new study led by the University of Utah, researchers found that the Fremont used small, frequent fires, a practice known as cultural burning, which reduced the risk for large-scale wildfire activity in mountain environments on the Fish Lake Plateau — even during periods of drought more extreme and prolonged than today.
The researchers compared lake sediment, tree ring data and archaeological evidence to reconstruct a 1,200 history of fire, climate, and human activity of the Fish Lake Plateau, a high-elevation forest in central Utah in the United States. They found that frequent fires occurred between the years 900 and 1400, a period of intense farming activity in the region. Prehistoric cooking hearths and pollen preserved in lake sediment show that edible plant species dominated the landscape during this period, indicating that Fremont people practiced cultural burning to support edible wild plants, including sunflowers, and other crops. Large-scale farming ceased after the year 1400. Hunters and foragers, ancestors of the Ute and Paiute, continued to burn, although less frequently than during the farming period. After Europeans made cultural burning illegal, the ecosystem returned to be dominated by a thick forest of trees.