Giant Sequoia Wildfire Report

The National Park Service has released a report on the recent fires in giant sequoia groves. Long report — I’ll post onlt the discussion section here, for its conclusions about the efficacy of fuels treatments and Rx fire, and the need for more treatments.


Overall, the KNP Complex and Windy Fires burned all or portions of twenty-eight sequoia groves, burning a total of 6,109 grove acres out of an estimated ~28,000 grove acres rangewide. Although much of this acreage burned at undetected change to low severity (3,905 acres) and is expected to have beneficial effects on grove ecosystem functioning, a total of 2,204 acres burned at moderate to high severity. In previous recent wildfires that burned at moderate to high severity we have seen significant mortality of large giant sequoias (Shive et al., in review). For these two 2021 fires our preliminary estimates (based on mortality rates from these previous field surveys combined with severity mapping for these two fires) suggest a potential loss of giant sequoias over four feet in diameter between 2,261 and 3,637 large giant sequoias. These estimates need to be updated by field surveys in coming years to document the full impact of these fires. Current maps of fire severity and estimated losses from this report can be used to stratify field survey efforts across severity and anticipated mortality.

The findings in this report indicate that wildfires that burn under conditions that result in high to moderate severity fire effects are a significant threat to the persistence of large sequoias. Fires burning with large areas of high severity is a dramatic change from historic fire patterns. Data from previous prescribed burns, wildfires, and tree-rings indicate that prior to the impacts of climate change and fire exclusion, large numbers of large giant sequoias were not killed during fire events (Stephenson 1996).

Our analysis of the KNP Complex, as well as the Windy Fire Burned Area Emergency Response report, indicate that prescribed fire and thinning treatments can reduce fire severity and provide fire fighters with opportunities to safely control and manage wildfires in some locations under some conditions during wildfire events. These treatments may not be effective under all wildfire conditions but did appear to positively affect fire behavior and allow fire suppression in Giant Forest and other groves impacted by these fires.

The mortality values within this report are estimates of potential mortality. The mortality rates used for moderate severity fires do not reflect the highest mortality rate measured in post-fire sequoia groves (45% in Save the Redwoods League data for Nelder Grove) because we wanted to be conservative in our estimates. Moderate severity areas in particular should be tracked over time to assess how these rates vary by location over time.

The KNP Complex BAER report suggests a potential management action of replanting giant sequoias in high severity areas greater than 100 meters distant from intact sequoia grove areas. While planting of giant sequoias as part of reforestation, restoration, and plantation forestry has been done successfully in California (see project descriptions from Sierra Pacific Industries at and Fahey et al. 2012 and references therein), evaluating whether post-fire seedling densities are sufficient to restore giant sequoias to burned areas should be done prior to moving ahead with active reforestation. In addition, areas proposed for reforestation should be evaluated for their potential to persist under a changing climate. The National Park Service memo regarding climate change adaptation and the framework focusing on Resist, Accept, Direct (NPS 2012) and the USFS General Technical Report 270 (Meyer et al 2021) are useful frameworks for evaluating restoration areas within a climate change context.

Finally, these ecosystems will continue to see wildfire. Grove areas that were in the fire perimeters but that had very little or no wildfire (“undetected change”) may still be at risk of severe fire in the immediate future. In areas where surface fuels were removed and tree densities were reduced, reburning is unlikely for ~10 years, giving ample opportunity to plan for the next wildfire or prescribed burn. Although reburning at low severity would be desirable, high severity reburns are of concern. Many past high severity burn areas in mixed conifer forests, which are a similar fuel type, have reburned severely due to the high fuel loads created by dense fire-killed trees that eventually fall to the surface, and vigorously regenerating shrubs (Coppoletta et al., 2016; van Wagtendonk, 2012). The potential for reburning at high severity in sequoia groves should be a priority for field investigation and where such an outcome seems likely, these areas should be targeted for fuel reduction work.

23 thoughts on “Giant Sequoia Wildfire Report”

  1. No matter how many times the truth of climate change is defined as a clear and present danger and is right now actively wiping out the last of the giant sequoias at a rate of ~10% a year over the past two years all you chainsaw junkies won’t look at or address the cause of the problem, which is too much carbon in the atmosphere making fire weather more consistently catastrophic. But not to Smokey Wire folks.

    To you, it’s a management issue; a just not enough chainsaws destroying the forest issue; a just not enough carbon off gassed from industrial logging issue, a just not enough carbon off gassed from controlled burning issue. It’s quite literally the definition of insanity! As the article clearly states:

    “Data from previous prescribed burns, wildfires, and tree-rings indicate that prior to the impacts of climate change and fire exclusion, large numbers of large giant sequoias were not killed during fire events (Stephenson 1996).”

    • I’m not sure why I am wasting my time but in your quote, it clearly says that “prior to the impacts of climate change and fire exclusion”. Fire exclusion has left forests across the west denser and less resilient to disturbance. We can either reduce those densities while we work on solutions to address climate change or not and lose what little we have left in wildfires exacerbated by climate change and uncharacteristically high fuel loads. It is not a question of ‘either-or’ but of ‘yes and.

  2. “areas proposed for reforestation should be evaluated for their potential to persist under a changing climate.”

    I don’t know who will be evaluating this, but as a person who worked with conifer germplasm…I can only say the only honest thing to say is “we haven’t a clue.” That is, predicting how GS seedlings will do under conditions of unknown future climates as experienced by them with varying soils and microsite conditions. Maybe they really mean “put them in microclimate conditions as close as possible to where GS is currently flourishing”, and the other is just a token wave of the hat to climate change as a factor. I hope they don’t really believe that they can predict the future climate at the level of detail that seedlings and trees experience it.

    • I don’t think it is a good idea to replant areas still filled with dead trees, here in California. The probability of re-burns is too high to make reforestation worthwhile. I guess after it does burn again, then the land will be able to accept planted trees. That is the reality in these forests. That situation is a consequence of not salvaging thick stands of dead trees, (through snag thinning).

    • Nice to see you posting an article that advocates for active management to restore ecosystems degraded by fire exclusion and pushed to the brink of a state change by climate acerbated wildfire impacts. Something I agree with you on for once.

    • Dealing with climate change will be a long-term effort. However, we can deal now with helping sequoia stands be more resilient to whatever changes are coming.


        So, apparently you disagree with Dr. Veblen, Steve?

        • Yes, Matthew, I do agree with Professor Veblen. But in the quote he addresses only climate change. However, if we do nothing to address forest health and resilience, then the effects of climate change will only be worse. IMHO, through active forest management we can help forests survive the changes that climate change has brought and will bring.

          FWIW, I argue that we can’t just walk away from current conditions and devote our efforts and funding primarily to reducing GHG emissions. For example, The World Health Organization estimates that about 9.3 million people die each year from diseases such as malaria, malnourishment, the lack of clean water and adequate sanitation, indoor air pollution, and so on. There is much we can do NOW to address these problems while we work to reduce emissions.

    • Thanks Matthew, I think that piece is worthy of a separate post. I think the problem and solution are a bit more complex than Veblen lets on.

        • Matthew, what’s your take? Should we undertake any form of active forest management to help forests become more resilient to current and future stressors?

          • Howdy Steve,

            You have asked this type of question before, and I have responded. Yes, I support some forms of “active forest management.” Examples would include, letting more naturally-caused wildfires burn (Something that most forest/fire ecologists also agree with). Removing and or upgrading fish passage culverts to improve overall forest and ecosystem health (Some estimates I’ve seen are that upwards of 80% of culverts on the national forests are currently impassable to fish, including threatened species). I support some hand-thinning of saplings, small trees and underbrush in certain, specific cases and ecosystems, I support the Legacy Roads and Trails Act (which my organization played a central role in getting permanently authorized and funded for the next five years to the tune of $250 million). I also of course aggressive home-hardening and mandating effective FireWise principles in all parts of the Wildland Urban Interface, which would not only save lives, protect firefighters and emergency responders, but it would also go a long ways toward a future where more fire is returned to fire-dependent ecosystems. Finally, I support aggressive and immediate climate action, which as Dr. Tom Veblen points out, the better chance we have to save forests.

            • Thanks for your reply, Matthew. IMHO, the activities you describe will not be enough to help forests be resilient to climate change. The IPCC notes that climate change — warming — will continue for decades or centuries, even after GHG emissions are slowed to Paris Agreement levels.

              • Thanks Steve. IMHO, the commercial logging activities you advocate for will not be enough to help forests be resilient to climate change and, in fact, may cause significant long-term damage to forests, soils, wildlife, and watersheds. Also, according to researchers based at Oregon State University and the University of Idaho “logging is by far the number one source of greenhouse gas emissions in Oregon.” See:

                  • Tell me more about what you mean by “thinning.” I’ve noticed that “thinning” can mean everything from cutting down a 4″ diameter sapling by hand with no heavy equipment to cutting down larger native trees with heavy equipment.

                    • Does it matter, Matthew? In some of the giant sequoia (GS) stands I’ve seen, “large” white fir are competing with the GS for moisture. White fir is very good at taking up moisture. If the white fir are of commercial size, sell the logs. If they’re smaller, make biomass energy or biochar, or firewood, or use them in streams for fish habitat. Commercial products or not, these white fir have to go, to give the GS a better chance at surviving.

                    • It is well known that soil compaction is a big problem for giant sequoias. There is no way we should allow heavy equipment in the groves. Of course, there could be some creative techniques which minimize compaction. Endlining (the use of long cables to winch logs to skid trails) and directional felling could make harvesting some of the logs possible. The rest would have to be dealt with, by hand, in the form of burn piles.

                      That being said, GS are not really in such great danger of going extinct. They do seem to grow well as ornamentals, in a wide variety of locations. The natural groves are in great danger to wildfires. What happens to GS plantations that are reaching 50 years old?

  3. If we could ‘magically-fix’ our climate to some unknown point which would impact our current world the least, we would still see massive and intense wildfires in our National Forests. When you exclude so many important variables, such ‘analysis’ seems as hollow (and flammable) as an empty cardboard box. How would a new climate deal with hundreds of millions of dead trees, just in California, alone? How many decades would it take to slow and then reverse ‘climate inertia’? My guess is that current dry forests would burn in the time it would take to ‘change our climate’.

    There are numerous Giant Sequoia plantations around, planted in the 70s. We could probably learn some things by studying the dozens of them, scattered through the Sierra Nevada.,-120.3314787,144m/data=!3m1!1e3?hl=en

  4. Sierra Nevada forests are doomed to burn at high severity under climate change and our lack of will to do what is needed. Thinning is a tool in the box, but it is not feasible at the scale necessary to create landscape resilience, mostly due to slope constraints and lack of volume to pay for the treatment.

    If you live in the Sierra, look out your window right now and you’ll see proof we haven’t learned anything and do not intend to do what is needed. Perfect prescribed fire weather conditions and fuel moistures occur across the Sierra right now and the next 5 days, yet there’s no smoke.

    Grizzly Flats burned down in Caldor, yet 10,000 acres of USFS land adjacent to the town, mostly easy ground, had been NEPAed for Rx fire and several thousand acres of thinning. They got the logging done, but never did the burning. Caldor would have been a different story had the burning been done.

    We know what needs to be done and we’ve known for more than 20 years. Yet very little has changed. Hire a ton of people and get out the drip torches. If the crews are not burning they should be prepping. If they are not prepping, they should be burning. We have enough NEPAed ground to keep crews busy for years, during which more ground can be NEPAed. Not to mention, all the science shows spotted owls do just fine with Rx fire, so bag as many acres as can be accomplished each open window, then prep for the next window. The more acres Rx burned, the easier it will be to bag larger burns.

    • “Perfect prescribed fire weather conditions and fuel moistures occur across the Sierra right now and the next 5 days, yet there’s no smoke.”

      How many fire-qualified people are ready and available to work on prescribed fires, right now? My guess is; very few. (Remember, too, that SoCal has been under Red Flag Warnings and Santa Ana winds.)


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