Study shows Western Apache peoples used more effective controlled burns long before U.S.

A study done in collaboration with multiple universities, including the University of Arizona, analyzed tree rings to prove that the Western Apache people were using small controlled burns to mitigate wildfire risk long before the U.S considered it a good strategy.

UA researcher Tom Swetnam says a century of just putting out fires led to vegetation buildup, especially in Arizona.

“The forestry and government stopped the Native American people from burning, and they’ve been putting fire out for 100 years," Swetnam said. "So most landscapes in Arizona have not had a fire for over 100 years. So now they’re [the U.S.] starting to put fire, to use fire, controlled fire where they can.”

He says the tree ring study proves the oral histories that Western Apache people were using controlled small fires to mitigate wildfire danger. And that there are lessons for current fire management.

The report also shows those burns were frequent enough to break down the correlation between hot and dry conditions — and the risk of fire. And the smaller the fire, the more effective in controlling the fuels.

“So [the Western Apache] people using fire, and increasing the frequency, actually made these forests probably more resilient and more able to withstand droughts and not have high intensity fires like we’re seeing today," Swetnam said.

He says prescribed burns are not up to the frequency used in the past.

Swetnam also says they plan to do more studies on different tribes, as the Western Apache were not the only Indigenous communities using controlled burns.

"I think as we expand both our tree ring fire history and other paleo, long time fire history studies, and talk to Native people and collaborate with Native people, Indigenous people — on what they know and understand about fire — we'll learn that the story is more complicated," Swetnam said.

He says there may have been different strategies.

"When you look at the history of ecology and landscapes and the history of people, it's not all the same everywhere. Not every tribe probably used fire the same way. And so there's going to be different stories that come out of studies elsewhere in the Southwest," Swetnam said.