Field Trip · The Washington Post

Yosemite National Park

June 28, 2023·56 min·4 clips

Tara Fouchmore of the Southern Sierra Miwok describes how tribal fire management — called vandalism in an 1860 newspaper — was actually thousands of years of systematic agricultural science that made Yosemite's famous landscapes possible.

1. Field Trip, a Washington Post podcast hosted by Lillian Cunningham, opens its first episode inside the Mariposa Grove of Yosemite National Park to examine how giant sequoias are under existential threat from catastrophic wildfire. 2. Forest ecologist Garrett Dickman is Yosemite's tree scientist; superintendent Cicely Muldoon manages the park's $30 million annual budget and 750 summer staff; Tara Fouchmore is tribal secretary of the Southern Sierra Miwok; Irene Vazquez is Yosemite's first cultural ecologist. 3. The episode's core question is: how does the way national parks are protected need to change in the era of climate change, and what does Yosemite's fire crisis reveal about the consequences of a century of wrong decisions? 4. Cunningham establishes that the Mariposa Grove's 500 ancient sequoias are where the national park idea was born: Abraham Lincoln signed the Yosemite Valley Grant Act in 1864 to protect this grove, and Congress modeled Yellowstone on its language and concept eight years later. 5. Garrett Dickman explains that giant sequoias can survive traditional ground fire because their bark at the base is up to two feet thick, airy, and spongy, leaving only black cat face scars; the trees also produce bitter, tannin-rich sap that repels insects and fungi. 6. Giant sequoia seeds require fire to open their cones and reproduce, meaning fire suppression also blocks the birth of new trees. 7. Modern catastrophic wildfires reach 300-foot flame lengths, exceeding the trees' 200-250 foot height; once flame enters the canopy where bark is thin, a redwood botanist described the result as the trees boiling to death. 8. More than 7,000 giant sequoias died in a single recent fire, representing over 10 percent of all sequoias in the High Sierra; since sequoias exist only in this range, any lost are gone permanently. 9. On July 7, 2022, the Washburn Fire started heading toward the Mariposa Grove; Dickman prioritized the Grizzly Giant first and his crew of 10 spent one hour clearing each fairy ring — a quarter-acre circle of debris around each tree — using chainsaws and heavy rakes. 10. Dickman slept in the back of his truck during 16-hour shifts; the crew cleared fairy rings around more than 100 trees before the fire turned away from the grove and was fully contained by early August. 11. The Grizzly Giant was also the site where President Theodore Roosevelt and John Muir camped in 1903, developing their ideas about conservation in America. 12. Tara Fouchmore explains that the Southern Sierra Miwok are directly descended from Chief Tenaya, the last great chief of Yosemite, and that her people lived in the valley for at least 8,000 years before being forced out by a state-sponsored militia in the 1850s. 13. Fouchmore describes tribal land management as systematic scientific agriculture conducted over thousands of years through experimentation — not the passive hand-to-mouth existence depicted by settlers — including deliberate fire management for forest health. 14. The Southern Sierra Miwok used fire in two ways: allowing natural lightning fires to burn and deliberately setting fires themselves, which maintained open meadows, used smoke as a pesticide for black oaks, kept forest floors clear, and opened sequoia cones. 15. John Muir called native people savages and wrote they seemed to have no right place in the landscape; an 1860 article called tribal burning vandalism by vandal hands; Muir's view that all fire was a threat influenced policy toward total fire suppression on public lands. 16. Irene Vazquez, Yosemite's first cultural ecologist and a Southern Sierra Miwok member, was appointed to restore Indigenous ecological practices including controlled burning of black oak groves in the valley. 17. A century of fire suppression left forest floors covered in thick matted debris, turned meadows into dense forest, sickened black oaks, and blocked new sequoia births; by the 2000s, Vazquez describes the groves as deteriorated, sad, and disrespected. 18. The park now conducts pile burns — gathering debris into piles and burning them — and broadcast burns, where a low-intensity fire is monitored as it moves through the forest; in areas with prior prescribed burns, sequoias were far more likely to survive the Washburn Fire. 19. Cunningham records inside 30 simultaneously burning bonfires with flame lengths of 15-20 feet during a pile burn near El Capitan, and audio producer Emma Talcoff's microphone cover melts from the heat. 20. Listeners interested in environmental journalism, national park history, Indigenous land rights, or the policy failures behind today's wildfire crisis will find this episode substantive and emotionally grounded; those seeking lighter nature content or travel advice will want a different episode.

As heard by us

A Yosemite story that makes protection the real tension.

The episode treats Yosemite as a story about memory, fire, and the work of keeping a grove alive. It starts with the host's childhood love of national parks, then moves into the pressure around Mariposa Grove, where helicopters, radio chatter, and the words "air attack" make a…

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When Yosemite catches fire, every detail starts to matter.

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