Can We Save the Redwoods by Helping Them Move?
Can We Save the Redwoods by Helping Them Move?
Excerpt from this New York Times story:
Giant sequoias live only in scattered groves, at midelevations, on the southwestern side of the Sierra Nevada. Milarch thought that as the world warmed, the unique conditions in which they thrived — well-drained soil that’s neither too hot nor too cold and that is also fed by water from snow melting upslope — would disappear, eventually leading to the trees’ extinction.
Some, though not all, experts share these worries. “It’s highly likely that many of the giant sequoias in their current groves may not make it for the next century,” Park Williams, a climate scientist at the University of California, Los Angeles, who focuses on the Western United States, told me. He notes that the soil is becoming drier in the southern Sierra Nevada, and snowpack is disappearing earlier in the year, ushering in a longer dry season. “We’re already pushing up against the boundaries of what these trees can tolerate,” Williams says. Indeed, in 2020, one of the trees Stielstra visited years earlier on his trip, known as the Waterfall Tree, was killed by wildfire, after having survived climatic lashings for millenniums.
This problem — a species under increasing threat in the place it has long inhabited — isn’t limited to giant sequoias. According to the International Union for Conservation of Nature, more than 12,000 species are in similar situations. The question is what, if anything, can be done to prevent a raft of extinctions driven by our remaking of the earth’s climate. For Milarch, the answer was clear. He ascribed to something called “assisted migration”: moving species to more hospitable areas. Of course, you can’t move a massive, 200-foot tree itself, so Milarch learned to grow new trees from samples he had collected in order to plant these genetic copies beyond the tree’s current range. Stielstra was taken with this idea (though he would later be unable to find any scientists who agreed with Milarch’s claim that the genetics of specific “champion” trees were special). Not only would the species be more likely to survive, he thought, but because the trees suck so much carbon out of the atmosphere, they could also help fight climate change. By the end of the trip, Stielstra resolved to move some of Milarch’s trees to Seattle.
Stielstra knew that Milarch would send him coast redwoods, a close relative of the giant sequoia (both species are commonly referred to as “redwoods”). And he knew they could survive Seattle’s climate: Three giant sequoias, about 80 feet tall, were growing by the entrance to a freeway that passed through his neighborhood, and there were groves of both coast redwoods and giant sequoias, healthy and majestic, in the Washington Park Arboretum that were planted decades earlier.