WHAT DOES THE The Science Behind the Smoke
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he summer of 2021 was another historic fire season for western states with mega-fires like the 900,000-acre+ Dixie Fire and the 221,000-acre+ Caldor Fire, which crossed into the Tahoe Basin and garnered international attention. As the Tahoe Rim Trail Association grapples with how best to preserve and improve the trail experience during the West’s intensifying fire seasons, the Association is leaning into the science behind these mega-fires and taking a deeper look at why these fires are growing so big, how fires are managed, and what individuals and communities can do to help mitigate the risk of future mega-fires. Historically, and under President Theodore Roosevelt, the role of the newly formed US Forest Service (USFS) was to manage timber production and the health of US forests to provide a sustainable supply of timber for a rapidly growing country. The USFS based its management approach on European practices which relied heavily on fire suppression to protect the economic value of the timber. Eventually, as wildfire seasons grew in length and intensity due to more fuel accumulation throughout western forests, the catastrophic consequences of decades of suppression efforts highlighted the need for fire on the landscape and the deficiencies of a suppression-only management strategy towards wildfire. After 13 smokejumpers perished in the Mann Gulch fire in 1949, the USFS reevaluated its
forest and fire management practices. It created the Rocky Mountain Research Station Missoula Fire Sciences Laboratory to provide cutting-edge wildfire science and technology. The new areas of study evaluated when, where, and how to fight wildfire while also balancing the ecosystem’s dependence on occasional low-intensity wildfire. Wildfire science has provided evidence that the mega-fires the West has experienced in the past decade are the result of excessive amounts of fuels on the forest floor, climate change, and also an increase in human traffic in forested and/or remote areas. Both good and bad fire exists. Bad fire cannot be addressed without good fire, and prescribed burns are one possible solution to reduce the amount of fuel in the forest. A wildfire at the right place and time can help restore the health of fire-dependent ecosystems by reducing the number of hazardous fuels, removing invasive species which threaten the health and survival of native species, minimizing the spread of disease and pest insects, improving soil health by recycling nutrients back into the soil, and promoting the growth of trees, wildflowers, and plants. Prescribed fires and well-managed low-intensity wildfires reduce the risk of unwanted wildfires in the future. Sara McAllister, Ph.D., a Research Mechanical Engineer at the Missoula Fire Sciences Laboratory notes, “you’re really not going to
