What If Gone

Species → Giant Sequoia

Giant Sequoia

Sequoiadendron giganteum

Fewer than 80,000 trees in total, occupying an actual area of just…
Extinction risk Endangered
Foundation speciesTemperate forestClimate changeCatastrophic decline
Giant Sequoia (Sequoiadendron giganteum)
Photo: Tuxyso, Wikimedia Commons (CC BY-SA 3.0)

What if it disappeared?

Impact Major
Castle Fire

The Castle Fire alone killed 10 to 14% of all large giant sequoias on Earth — 7,500 to 10,600 trees — with mortality reaching 93% in high-severity burn areas, compared with just 7% in low-severity areas.

Documented
Detail

Stephenson, N. et Brigham, C. (2021). Preliminary Estimates of Sequoia Mortality in the 2020 Castle Fire. U.S. Geological Survey, Western Ecological Research Center et National Park Service.

Within the fire perimeter itself, 31 to 42% of large sequoias died — far above the average across the species' total range, since the fire did not burn that whole range with equal intensity. The species, though historically well adapted to fire thanks to thick bark and cones that open under heat, had never experienced mortality at this scale in its documented history.

Over 2 fire seasons

Counting the Castle Fire (2020) and the KNP Complex Fire (2021) together, 19% of the entire mature giant sequoia population disappeared in just two years — but groves that had received prescribed burns within the prior decade were four times more likely to survive, a measure that prevented roughly 1,900 additional deaths.

Documented
Detail

Dixon, D.J., Das, A.J., Dong, X., Latimer, A.M., Soderberg, D.N., Stephenson, N.L., Caprio, A.C. et Jin, Y. (2026). Previous prescribed burns saved thousands of ancient sequoias during historically unprecedented wildfires. Nature Communications.

The study covers roughly 26,400 sequoias across 19 groves. Recent prescribed burning reduced a given tree's risk of death by 77% — and if every grove had received this treatment before the fires, an estimated 3,900 additional sequoias would likely have survived, according to the authors.

Not measured to date

The giant sequoia is considered a foundation species of its grove, but no study measures what would happen to the understory, microclimate, or associated species if a grove lost its large trees — available research documents their mortality from fire, not their structuring role for the rest of the grove's ecosystem.

Insufficient

Documentation

Last verified: August 14, 2026