BOULDER CREEK — A recently published, multiyear study about the recovery of redwood trees in Big Basin Redwoods State Park after the CZU Lightning Complex fires shows that long-stored carbon reserves and ancient, dormant buds within redwood trees allow the plants to recover quickly after a catastrophic fire.
The study was sponsored by the National Science Foundation and Save the Redwoods League, with additional support from California State Parks and Sempervirens Fund, and was authored by a team of scientists and researchers from Northern Arizona University led by Drew Peltier, biologist and assistant professor at University of Nevada, Las Vegas, formerly with Northern Arizona University.
“Some of the results of this study suggest many of the redwoods at Big Basin were actually well prepared for this fire event,” said Peltier in a statement. “Coast redwoods are extremely fire-adapted and perhaps unusual in that they resprout after disturbances like fire. We were amazed to discover how they actually do that physiologically.”
The 2020 CZU Lightning Complex fires spanned more than 135 square miles in the Santa Cruz Mountains and burned about 97% of Big Basin Redwoods State Parks, destroying nearly every structure and laying waste to the park’s flora and fauna.
According to the study, long-living organisms such as coast redwoods often develop “insurance strategies” to increase their resilience in times of resource shortages, stress or traumatic events such as pest outbreaks and wildfires. After a fire, burned redwoods recover by resprouting from roots, trunk and branches, which are supported by reserves of carbon, consisting primarily of sugars and starch, within the tree that can be years and even decades old.
The research team from Northern Arizona University collected samples of small redwood tree sprouts at Big Basin following the CZU fires. Using a unique mini carbon dating tool at Northern Arizona University, the team studied the samples to determine the age of carbon reserves used to grow new leaves.
Researchers estimated that in some of the trees that were studied, up to half of the sprout carbon was created through photosynthesis nearly 60 years prior. According to the study, direct use of this old carbon has rarely been documented and never in such large, old trees as some of the old-growth trees in Big Basin that are more than 1,500 years old.
Dormant sprouts emerged from buds that are estimated to be waiting for a traumatic event under redwood bark for centuries. According to the study, “For organisms with millennial lifespans, traits enabling survival of infrequent but catastrophic events may represent an important energy sink. Remobilization of decades-old photosynthate after disturbance demonstrates substantial amounts of nonstructural carbon within ancient trees’ cycles on slow, multidecadal timescales.”
“The CZU Fire consumed all of the leaves on some of the tallest and oldest trees in the world, yet many are recovering,” said George Koch, professor of biological sciences at Northern Arizona University, in a statement. “Redwoods’ scientific name is sempervirens, which means ever-flourishing. It’s very satisfying to have learned a bit more about how this remarkable species lives up to its name.”
As part of the study, the team installed cameras in Big Basin’s tree canopy to monitor the progression of growth. The cameras are part of the university’s PhenoCam Network, which tracks vegetation growth and seasonal changes in ecosystems around the globe.
“This fascinating research reveals how coast redwoods have been able to adapt and survive for millennia by drawing on carbon they’ve stored for decades to give them new life,” said Joanna Nelson, director of science and conservation planning for Save the Redwoods League in a statement. “These discoveries underscore why we have to protect the last remaining old-growth redwood trees, use best forest management practices and continue to restore younger second-growth forests, so they’ll have the capacity for resilience to future wildfires and other effects of climate change.”