The idea seemed self-evident: Why not replant redwoods to replace the giants destroyed by the terrible California fires of 2020 and 2021? The majestic Sierra Nevada trees, among the tallest and oldest in the world, were decimated by megafires fueled by drought and climate change. By nature, redwoods love flames, which burst their cones and release their seeds. But these fires had spread from treetop to treetop, right up to the crowns of the trees (sometimes 80 meters high), leaving the cones destroyed to the point of threatening the regeneration of certain groves.
When the National Park Service (NPS) crunched the numbers in 2022, it estimated that over 15,000 trees over one meter in diameter had been lost. In other words, 20% of the global stock. Giant redwoods (Sequoiadendron giganteum) are a unique species – not to be confused with their cousins, the Pacific Coast redwoods (Sequoia sempervirens), with their tapering trunks that are taller but narrower. They grow only on the western slopes of the Sierra Nevada, at altitudes of between 1,500 and 2,100 meters.
Growing to a venerable age (up to 3,000 years), giant sequoias are more than trees: They are icons, symbols of stability in a world of transience. In the 19th century, American pioneers felled many, to show their compatriots the wonders of the West as it was being conquered. But even then, their ardor was curbed. As early as 1864, amid the Civil War, the American government decided to protect them by granting the state of California sovereignty over Yosemite Valley and the nearby Sequoia Park forest, on condition that they be preserved for the public in the name of the common good – a world first. Years later, after the creation of Yosemite National Park, names were assigned to the great trees. President this, General that, Congress, Senate: A sign of respect still attached to institutions at the time.
General Sherman survived the fire of September 2021 (its 30-meter trunk was encased in fireproof material). At 84 meters tall, it is as fit as ever in its grove, surrounded by a marked trail for tourists. But you only have to stray a little from the Generals' Highway, in Sequoia National Park, to see an army of charred trunks. In the steep canyon of Redwood Mountain Grove, trees over 2,000 years old have been destroyed. This is one of six groves where the NPS decided in early October to replant seedlings, believing that the redwoods would not come back on their own.
Among environmentalists, the reforestation project has provoked an outcry. There are two types of opposition. From a scientific point of view, some are concerned about the genetic modification that could be introduced into these natural treasures by "importing" seedlings from other forests. The NPS project involves using shoots from species more resistant to heat. They are also grown in nurseries, several of which have recently been infected with pathogens, raising fears of disease transmission, according to René Voss, a lawyer for the collective of organizations opposed to the project.
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