Damn you, Smokey! Turns out fire suppression is a really bad thing if you want to avoid massive large-canopy-killing crown fires.
Unprecedented study relies on more than 1,500 years of tree-ring data and hundreds of years of fire-scar records gathered from Ponderosa Pine forests
Today’s mega forest fires of the southwestern U.S. are truly unusual and exceptional in the long-term record, suggests a new study that examined hundreds of years of ancient tree ring and fire data from two distinct climate periods.
Researchers constructed and analyzed a statistical model that encompassed 1,500 years of climate and fire patterns to test, in part, whether today’s dry, hot climate alone is causing the megafires that routinely destroy millions of acres of forest, according to study co-author and fire anthropologist Christopher I. Roos, Southern Methodist University, Dallas.
The researchers found that even when ancient climates varied from each other — one hotter and drier and the other cooler and wetter — the frequencies of year-to-year weather patterns that drive fire activity were similar.
The findings suggest that today’s megafires, at least in the southwestern U.S., are atypical, according to Roos and co-author Thomas W. Swetnam, the University of Arizona. Furthermore, the findings implicate as the cause not only modern climate change, but also human activity over the last century, the researchers said.
“The U.S. would not be experiencing massive large-canopy-killing crown fires today if human activities had not begun to suppress the low-severity surface fires that were so common more than a century ago,” said Roos, an assistant professor in the SMU Department of Anthropology.
Today’s extreme droughts caused by climate change probably would not cause megafires if not for a century of livestock grazing and firefighting, which have combined to create more dense forests with accumulated logs and other fuels that now make them more vulnerable than ever to extreme droughts. One answer to today’s megafires might be changes in fire management.