Dear EarthTalk:

What is the status of California's giant sequoias trees and what's being done to save them from extinction?

M.L., Sacramento, CA

Giant sequoias, which can grow upwards of 300 feet tall with circumferences of 90+ feet around at ground level, are among the largest and longest living species on the planet today. Some are over 3,000 years old. But climate change, human activities and wildfires are threatening their very existence in their native habitat on the western slopes of California’s Sierra Nevada mountains.

Biologists estimate there are about 80,000 naturally occurring giant sequoias left there and worry that another bad wildfire year—like 2015, 2017 or 2020, when National Park Service biologists clad the lower flanks of the biggest trees with tin foil to deter the flames—could decimate those remaining trees.

Giant sequoias have evolved to withstand moderate fires, but the recent infernos, exacerbated by climate change, have been catastrophic. Not only do these fires destroy the trees directly, they also hinder the natural reproduction process by killing young sequoias and preventing seeds from germinating.

While fire has been the most immediate threat in recent years, climate change in general is altering the trees’ environment—and may be the final nail in their coffin. Rising temperatures, prolonged droughts and erratic precipitation patterns have weakened the trees, making them more susceptible to pests and disease, and disrupting the natural fire regime that they have depended on for regeneration for millennia.

To mitigate the impacts of climate change, researchers and conservationists are studying how these trees respond to changing environmental conditions. They are also implementing measures like controlled burns to mimic natural fire cycles and create a more suitable habitat for the sequoias.

Human activities, such as logging, urban development and recreation further exacerbate the challenges faced by giant sequoias. Urbanization around these groves disrupts their ecosystems, and recreational activities can harm their shallow root systems. Efforts are also being made to limit human impacts in sequoia territory. Strict regulations on logging, urban expansion and recreational activities near these groves aim to preserve the natural ecosystem and minimize disturbances to the trees.

Moreover, collaborative initiatives between government agencies, conservation organizations, and local communities are crucial for the long-term protection of these ancient giants. Public awareness campaigns, educational programs, and eco-tourism practices that emphasize responsible visitation also play a vital role in ensuring the survival of these magnificent trees. Whether or not our grandchildren will get to visit these giant sequoias may well depend on our ability to rein in carbon emissions here and around the world in time to stave off cataclysmic climate change. Indeed, the fate of these giant trees, as well as thousands of other plants and animals, hangs in the balance.

CONTACTS

• Helping or hindering? US scientists debate how to save giant sequoias, https://phys.org/news/2023-09-hindering-scientists-debate-giant-sequoias.html
• Save The Giant Sequoias, https://www.savetheredwoods.org/redwoods/fire/save-the-giant-sequoias/
• The race to save ‘awe-inspiring’ giant sequoias, https://yaleclimateconnections.org/2023/08/the-race-to-save-awe-inspiring-giant-sequoias/.

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