---
title: "A New Study Puts a Number on What Prescribed Fire Saved: About 1,900 Giant Sequoias"
description: "UC Davis researchers tracked roughly 26,400 individual sequoias through the 2020 and 2021 fires. Trees in groves that had been deliberately burned within the previous decade were about four times more likely to survive."
category: "California"
category_url: https://herald.la/category/california
author: "Desmond Clarke"
published: 2026-07-30T22:53:30.000Z
updated: 2026-07-30T22:53:30.000Z
canonical: https://herald.la/article/a-new-study-puts-a-number-on-what-prescribed-fire-saved-about-1-900-giant-sequoi
tags: ["giant-sequoias", "prescribed-fire", "wildfire", "sierra-nevada", "forest-management"]
---
# A New Study Puts a Number on What Prescribed Fire Saved: About 1,900 Giant Sequoias

UC Davis researchers tracked roughly 26,400 individual sequoias through the 2020 and 2021 fires. Trees in groves that had been deliberately burned within the previous decade were about four times more likely to survive.

For decades the argument for setting deliberate fire in a sequoia grove has rested
on ecology and on the judgment of the people who manage the groves. A study
published in Nature Communications puts an arithmetic result next to it.

Researchers led by Dan Dixon, a postdoctoral researcher at UC Davis, tracked
roughly 26,400 individual giant sequoias in Sequoia and Kings Canyon National
Parks through the fires of 2020 and 2021, comparing trees in areas that had
received prescribed burns with trees that had not. Sequoias in areas burned
deliberately within the previous ten years were
["about four times more likely to survive," Dixon said](https://laist.com/news/climate-environment/study-protecting-california-giant-sequoias-prescribed-fire).

## The two numbers that matter

Scaled across the study area, the researchers estimate that prescribed burning
[saved roughly 1,900 giant sequoias](https://www.ucdavis.edu/climate/news/prescribed-burns-saved-thousands-giant-sequoias)
in those two fire years. The counterfactual is the harder number: had every acre
in the study area been treated in the preceding decade, an estimated 3,900
additional trees would have lived.

That second figure is the policy argument. It says the constraint was not whether
the technique works but how little of the landscape had been reached.

## What was lost

The fires that prompted the study were not ordinary. The National Park Service
estimated that the 2020 Castle Fire killed
[7,500 to 10,600 large sequoias](https://www.nps.gov/articles/000/wildfires-kill-unprecedented-numbers-of-large-sequoia-trees.htm),
between 31 and 42 percent of the mature giant sequoias inside its perimeter. The
following year, the KNP Complex Fire killed or was expected to kill
[1,330 to 2,380 large sequoias, and the Windy Fire 931 to 1,257](https://www.nps.gov/seki/learn/news/giant-sequoia-mortality-estimates-released-for-the-2021-knp-complex-and-windy-fire.htm).
Taken together, the 2021 fires alone removed something on the order of 3 to 5
percent of all the large giant sequoias on earth, since the species grows
naturally only in a strip of the western Sierra Nevada.

Giant sequoias are not merely fire-tolerant; they are fire-dependent. Their cones
need heat to open, their bark is built to survive low-intensity burns, and mature
trees historically shrugged off ground fire for two thousand years at a stretch.
What killed them in 2020 and 2021 was flame that reached the crown, which requires
a ladder of accumulated fuel that a century of fire suppression built.

## Why it is not simply done

Sequoia and Kings Canyon have run prescribed fire programs since the 1960s, which
is why the study had treated and untreated ground to compare in the first place.
Expanding that work across the roughly 75 groves in the Sierra Nevada runs into
obstacles that have little to do with whether the science is settled.

Burn windows are narrow: the weather has to be dry enough to carry fire and wet
enough to hold it. Smoke from a prescribed burn lands on communities in the San
Joaquin Valley that already carry some of the worst air quality in the country,
and air districts limit when crews may light. Agencies compete for the same
firefighters who are deployed to suppression through much of the year. And
liability has long discouraged private landowners, though California created a
claims fund in 2022 to absorb some of that risk.

None of those obstacles is imaginary, and none is answered by a study. What the
study does is set a price on delay, in trees, for a species that cannot be
replanted on any timescale that matters.

## Sources

- [Study: protecting California's giant sequoias from wildfire takes fire](https://laist.com/news/climate-environment/study-protecting-california-giant-sequoias-prescribed-fire)
- [Prescribed Burns Saved Thousands of Giant Sequoias](https://www.ucdavis.edu/climate/news/prescribed-burns-saved-thousands-giant-sequoias)
- [Wildfires Kill Unprecedented Numbers of Large Sequoia Trees](https://www.nps.gov/articles/000/wildfires-kill-unprecedented-numbers-of-large-sequoia-trees.htm)
- [Giant Sequoia Mortality Estimates Released for the 2021 KNP Complex and Windy Fire](https://www.nps.gov/seki/learn/news/giant-sequoia-mortality-estimates-released-for-the-2021-knp-complex-and-windy-fire.htm)