A new "super grove" of endangered coast redwood trees has arisen in California, thanks to a nonprofit group that planted 75 saplings at a park in San Francisco.
Since their species is endangered, any new community of coast redwoods would be welcome news. Yet these 75 saplings are also newsworthy for another reason: They're all clones, born of DNA that conservationists retrieved from ancient redwood stumps. Now growing together at the Presidio of San Francisco, they carry on a valuable genetic legacy that dates back thousands of years.
The trees were planted on Dec. 14 by Archangel Ancient Tree Archive (AATA), a nonprofit group that creates "living libraries of old-growth tree genetics." Each sapling was sourced from one of five ancient stumps in Northern California, remnants of redwoods that were all larger than the largest tree standing today, a giant sequoia known as General Sherman. After discovering the stumps were still alive, AATA co-founder David Milarch and his team led an expedition to clone them.
Pictured above, for example, is the 35-foot-wide (11-meter) Fieldbrook stump, left by a coast redwood that was about 400 feet tall and more than 3,000 years old when it was cut down in 1890. And pictured below is one of 20 saplings cloned from it:
Because they're clones of trees that were larger than any currently living redwoods, the AATA is calling these saplings "champion trees," a term for the largest tree of a given species. There's no guarantee they'll live up to that title, but their genes and protected location at least give them a chance. And they may also become champions in a broader sense, both for their own species and many others — including us.
A mature coast redwood can remove huge amounts of carbon dioxide from the air, the AATA points out, sequestering as much as 250 tons of the greenhouse gas per tree. They also perform other important ecosystem services, like filtering water and soil, and they're highly resistant to wildfires, droughts and pests.
Volunteers plant a coast redwood at the Presidio of San Francisco on Dec. 14, 2018. (Photo: Rob Lovato Victor Aquino)
"We're excited to set the standard for environmental recovery," Milarch says in a statement. "These trees have the capacity to fight climate change and revitalize forests and our ecology in a way we haven't seen before."
Once the source material is collected from a redwood stump, it takes about 2.5 years to cultivate the saplings and get them large enough to plant. The idea of cloning trees may sound "complicated and unnatural," the AATA acknowledges on its website, but this process is actually mimicking a natural kind of asexual redwood propagation.
In the wild, coast redwoods can reproduce by self-cloning from masses of unsprouted bud tissue known as burl, as the U.S. National Park Service explains:
"Occasionally, an almost perfect circle of redwood trees grows in the forest. These 'fairy rings' or 'family circles' sprouted from the basal burls of one parent tree, long harvested or fallen. ... If a redwood falls or is otherwise damaged, the burl may begin to sprout from the trunk or branch it developed on, sharing or taking over the established root system of the parent tree. The new tree is an exact clone of the original tree, carrying its genetic identity far into the future."
In addition to the Fieldbrook stump, which yielded 20 saplings, the AATA created clones from four other coast redwood stumps with diameters of at least 31 feet (9 meters): the Barrett stump (25 saplings), Barrett stump No. 2 (14 saplings), Big John stump (11 saplings) and Ayers stump (five saplings).
"These saplings have extraordinary potential to purify our air, water and soil for generations to come," Milarch says. "We hope this 'super grove,' which has the capability to become an eternal forest, is allowed to grow unmolested by manmade or natural disasters and thus propagate forever."