Windy Fire killed 35% of large giant sequoias in 7 groves
(And a rebuttal to Camp 70 Foresters from Chad Hanson)
Volume 2, Number 61 - Monday, July 8, 2024
Published every Monday and Thursday
Perspective
THE MOST RECENT of major fires in the Sierra Nevada that killed giant sequoia trees were the 2021 Windy Fire and the KNP Complex Fire.
Both were started by lightning on Sept. 9, 2021. The KNP Complex Fire burned more than 88,000 acres, mostly in Sequoia National Park. Further south in the Sierra Nevada, the Windy burned more than 97,000 acres, largely on Sequoia National Forest (SQF) and the Tule River Reservation.
According to a report from the National Park Service, updated about a year ago (HERE), scientists estimated that between 931 to 1,257 large sequoias were killed in the Windy Fire or would die in the next 3-5 years.
In that same report, the NPS said, “More than 85 percent of all giant sequoia grove acreage across the Sierra Nevada has burned in wildfires between 2015 and 2021, compared to only one quarter in the preceding century.” The park service also noted that the mortality was greatest in areas where fires burned at high severity.
A report published in April provides a more precise look at the impact of the Windy. Sampling seven giant sequoia groves, scientists found that 35% of large giant sequoias experienced mortality following the Windy Fire, and another 6% are anticipated to experience mortality by the third post-fire year.
They noted:
Large giant sequoia mortality was greatest in high-severity patches (73% mortality) compared to low-severity (0 to 4%) and moderate-severity (8%) burned areas within groves. In areas of very high severity … large giant sequoia mortality was 92%.
Regular readers may recall that former Forest Supervisor Teresa Benson signed decisions for the restoration projects related to the Windy Fire and the 2020 Castle Fire last December, just before her retirement from Sequoia National Forest.
Readers may also recall that on Feb. 22, the Sierra Club, Earth Island Institute and Sequoia ForestKeeper sued the Forest Service over the projects, the Forest Service calling them “large logging and vegetation management projects.” The litigation is still pending.
Authors of the April report about Windy Fire impacts are Marc D. Meyer and Travis Sowards of the USDA Forest Service, Pacific Southwest Region Ecology Program, Southern Sierra Province; Rebecca Wayman of the University of California Davis, Department of Environmental Science and Policy; and Beverly Bulaon of the USDA Forest Service, State and Private Forestry, Forest Health Protection, South Sierra Service Area. The authors thanked SQF and the USDA Forest Service’s State and Private Forestry Health Protection Program for funding the study.
Their report is entitled “Windy Fire Post-Fire Ecological Assessment: 2022 Field Inventory Report.” It focuses on a post-fire inventory of seven giant groves one year after the fire and assesses fire effects on large giant sequoias, stand structure and composition, and regeneration. It also prioritizes forest restoration and fuel reduction treatments.
The 88-page report contains a lot of information, along with priorities for forest restoration and fuel reduction treatments. It also shows that scientists and land managers are still working to understand better the impacts of fire and fuel and specifics about giant sequoia groves.
After referencing analyses conducted in the groves impacted by the 2020 Castle Fire, the authors of the Windy Fire report emphasized one point:
Collectively, these results strongly suggest that forest management efforts designed to reduce ladder and surface fuels can help minimize the impacts of uncharacteristic wildfires on large giant sequoias.
Here’s the report:
A rebuttal …
Last Monday, this newsletter included an article entitled “Camp 70 Foresters respond to Chad Hanson’s views on giant sequoias.” If you missed it, you can read it HERE. The Camp 70 Foresters are a group of former forestry classmates who attended the University of California Forestry summer camp near Quincy, California, in 1970 and graduated with B.S. degrees in Forestry. In the article published here on July 1, they were responding to comments Hanson made during a presentation at a Sierra Club meeting in Bakersfield in April. I reported on his presentation HERE.
Hanson wrote to me and asked if I would publish a rebuttal to the Camp 70 piece. That seems fair to me, so you will find it below.
Logging in remote forests does not protect communities, or sequoias
By Chad Hanson
I write this article in reply to a comment written by “Camp 70 Foresters”, who recently attacked me in Giant Sequoia News in the course of promoting a logging industry perspective on forest management (“Camp 70 Foresters respond to Chad Hanson’s views on giant sequoias”, July 1, 2024).
The Camp 70 Foresters would have us double down on logging in remote public forestlands under the rubric of “thinning,” supposedly to save communities and giant sequoia groves from wildfires. The foresters do not offer a single citation to any scientific source to support their position. Here’s why their approach would increase, not decrease, the threat of wildfires to communities while also degrading and harming giant sequoia groves and other forests (I have included numerous key scientific sources in hyperlinks).
The basic assumption of the Camp 70 Foresters—that wildfires burn more intensely in places due to dense forest conditions—is outdated and contradicted by the best and most comprehensive science. The U.S. Forest Service’s own scientists are now increasingly moving away from this old narrative. For example, in April of 2024, the Forest Service publicly promoted the findings of a comprehensive analysis of the 2020 wildfires in the Pacific Northwest. The Forest Service reported the following:
Researchers also found little difference in burn severity among stand structural types related to previous management in the 2020 fires. This finding suggests that forest management and fuel treatments may not be effective in mitigating fire severity during extreme fire weather. Rather, adaptation strategies for similar fires in the future could benefit by focusing on ignition prevention, fire suppression, and community preparedness.
The Forest Service scientists found that weather and climate change drove large wildfires, not dense forest conditions, suggesting that we focus our attention directly on creating fire-safe communities.
In another recent study by Forest Service scientists—this one including 30 years of data from 472 wildfires—the agency found that denser forests had lower wildfire severity due to microclimate effects that buffer dense forests from extreme weather driven by climate factors and climate change. The Forest Service scientists concluded that less dense, lower-biomass forests have “hotter, drier, and windier microclimates and those conditions decrease dramatically over relatively short distances into the interior of older forests with multi-layer canopies and high tree density…”
Tragically, the approach advocated by logging interests — removing vast numbers of live and dead trees across forest wildlands under the guise of thinning, fuel breaks, and community protection — is a proven failure. This approach is associated with the loss of many human lives and destruction of many thousands of homes in recent wildfires while also increasing carbon emissions that exacerbate climate change, which increases numerous threats to communities. The U.S. Forest Service and other land management agencies have known for years that wildfires spread much faster through more open forests, like those resulting from “thinning.” That means the fires reach communities in far less time when spreading through thinned forests, giving people and their animals less time to be safely evacuated.
The Camp 70 Foresters also have it wrong with regard to giant sequoias and wildfires. The conclusion that giant sequoias depend on higher-intensity fire to effectively reproduce did not originate with me. It came from reports and studies from U.S. government scientists, including the U.S. Forest Service. A 1994 study released by the Forest Service found that giant sequoias had been suffering a “massive failure of sequoia reproduction” over a century due to the lack of fire. But the study made clear that giant sequoias do not effectively reproduce in low-intensity surface fire areas, but instead need some patches of high-intensity fire to create the conditions for the growth of the next generation of sequoias. The study noted that the “Giant sequoia is what is known as a ‘pioneer species,’ requiring canopy-destroying disturbance to complete its life cycle.”
A 2011 study by Forest Service scientists found that giant sequoia regeneration was by far the highest in high-intensity fire areas, and observed that giant sequoia seedling survival is about 7 times higher in high-intensity areas than in lower-intensity fire areas.
To be clear, low- and moderate-intensity fire is natural in giant sequoia groves, too, just as high-intensity patches are natural. The species evolved with this mix of fire intensities. Recent wildfires in giant sequoia groves have, in fact, been heavily dominated by low to moderate-intensity fire, but it is in the higher-intensity fire patches where giant sequoias are regenerating best.
In contrast, where the Forest Service has conducted logging in giant sequoia groves under the banner of thinning and wildfire management, they have killed 83% of the young giant sequoias, devastating the next generation of sequoias and leaving behind a wasteland of stumps and barren ground.
The Camp 70 Foresters repeat the claim that 20% of all large giant sequoias were killed in the 2020 and 2021 wildfire seasons, but that claim is not based on any published study with external peer review. Rather, it is a preliminary claim based on limited data and anecdotal accounts that have since come into serious question. My own much more comprehensive research on this subject, still in preparation, is finding far lower levels of mature sequoia mortality from these fires. Until published, peer-reviewed science is available, people should be cautious about relying upon and repeating the claim that 20% of large sequoias were killed in 2020-2021.
Our best approach for public safety, climate change mitigation, and biodiversity is to recognize that wildfires are weather and climate events, and we would be best served by moving away from backcountry logging and focusing our efforts directly on helping communities become fire-safe through home hardening, defensible space pruning, and evacuation assistance.
Chad Hanson, Ph.D. is a research ecologist with the John Muir Project.
Wildfire, water & weather update
Wildfires and excessive heat throughout California, as you probably already know. This morning’s report shows that the Basin Fire, on Sierra National Forest, is 14,020 acres and 60% contained. At least the Red Flag Warnings (for wildfire) are gone this morning. The best Sierra Nevada weather forecasts are at NWS Hanford, HERE, and NWS Sacramento, HERE.
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Thanks for reading!
One thing I don't understand is how has it been determined that the sequoias called "dead" are, in fact, dead. Black trunks and all foliage burned away does not always equal dead. But perhaps the forest experts can describe the methodology that determined mortality.
Thank you for publishing the Chad Hanson rebuttal regarding the Camp 70 Foresters claims that you published last week ... I deeply appreciate the balance that is now achieved by the publishing of the CH rebuttal ...