Helping to Restore Giant Sequoias after Significant Wildfires

A Giant Sequioa tree seen from below, looking up to its tall trunk, branches and leaves. Photo by Adobe Stock images. 

BY CHRISTY BRIGHAM

There’s nothing like standing under a giant sequoia, the world’s largest tree. If you perch at a sequoia’s base and gaze up its massive red-orange trunk, it’s easy to feel infinitely small as your eyes follow red-orange bark hundreds of feet into the air, up to evergreen leaves that appear to mix with the sky itself. 

Giant sequoia bark is spongy and thick, an adaptation that has allowed these towering giants to evolve with wildfire and protect them against significant damage. At up to 18 inches thick, sequoia bark not only resists burning, it also insulates the tree against fire's heat. Should fire penetrate the bark and scar the living tissue, new growth may heal the scar. 

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A photo of Board Camp Grove after a wildfire burned through the area in 2020. Photo by NPS.

A photo of Board Camp Grove after a wildfire burned through the area in 2020. 

Fire plays a crucial role in the giant sequoia ecosystem. Fire scars in tree rings dating back 2,000 years show that widespread fires occurred naturally at intervals ranging from 6 to 35 years in these forests. However, as wildfires become more extreme, sequoias are dying. During 2020 and 2021, two major wildfires burned through numerous sequoia groves within Sequoia and Kings Canyon National Parks. Between 2020 and 2021, three major fires, the SQF Complex, the Windy Fire, and the KNP Complex, are estimated to have killed as many as 14,000 large giant sequoias, or 19 percent of all giant sequoias in their range. These losses were unprecedented and revealed a need for new approaches to studying and mitigating wildfire impacts. 

Giant sequoias have a short natural regeneration window after a wildfire. The trees capitalize on soil conditions and small canopy openings created by the fire.

In response to the recent large wildfires, a burned area emergency response team began an analysis to determine ground conditions and effective restoration activities. The team created a rehabilitation plan, which enables personnel to identify areas where sequoias will likely struggle to regenerate due to overstory losses and a high erosion potential that could remove any surviving sequoia seeds.

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Planning for the future. Giant sequoia cones collected from the handful of surviving trees in Board Camp Grove.

Planning for the future: giant sequoia cones collected from surviving trees in Board Camp Grove.

A vital component to implement restoration activities is the preparation of seed stock and seedlings so planting can begin after the environmental compliance process, analysis, and planning phases. Burned Area Rehabilitation funding is allowing the National Park Service to complete this preparatory work while completing the necessary environmental analyses. 

This work is groundbreaking in its effort to address forest ecological damage caused by a combination of more than a century of wildfire suppression and droughts in the Southern Sierra Nevada driven by climate change. As these rehabilitation projects continue into fiscal year 2024, park staff hope their efforts will allow giant sequoia groves to recover from wildfire and continue to thrill future generations of visitors.

Sequoia and Kings Canyon National Parks are currently inviting public review and comment on the environmental assessment for this project. Read all about the project and share your feedback between now and August 6 at: https://parkplanning.nps.gov/projectHome.cfm?projectId=107200

Christy Brigham is the Chief of Resources Management and Science at Sequoia & Kings Canyon National Parks