Barely a week ago, in a low-lying tract of southern Georgia’s pine belt, a half-dozen workers planted row upon row of twig-like poplar trees. These weren’t just any trees, though: Some of the seedlings being nestled into the soggy soil had been genetically engineered to grow wood at turbocharged rates while slurping up carbon dioxide from the air.
The poplars may be the first genetically modified trees planted in the United States outside of a research trial or a commercial fruit orchard. Just as the introduction of the Flavr Savr tomato in 1994 introduced a new industry of genetically modified food crops, the tree planters hope to transform forestry.
Living Carbon, a San Francisco-based biotechnology company that produced the poplars, intends for its trees to be a large-scale solution to climate change. “We’ve had people tell us it’s impossible,” Maddie Hall, the company’s co-founder and CEO, said of her dream to deploy genetic engineering on behalf of the climate. But she and her colleagues have also found believers — enough to invest $36 million in the 4-year-old company.
The company has also attracted critics. The Global Justice Ecology Project, an environmental group, has called the company’s trees “growing threats” to forests and expressed alarm that the federal government allowed them to evade regulation, opening the door to commercial plantings much sooner than is typical for engineered plants.
Living Carbon has yet to publish peer-reviewed papers; its only publicly reported results come from a greenhouse trial that lasted just a few months. “They have some encouraging results,” said Donald Ort, a University of Illinois geneticist whose plant experiments helped inspire Living Carbon’s technology.
Living Carbon’s poplars start their lives in a lab in Hayward, California. There, biologists tinker with how the trees conduct photosynthesis, the series of chemical reactions plants use to weave sunlight, water and carbon dioxide into sugars and starches. As a chemical process, it is far from perfect. Numerous inefficiencies prevent plants from capturing and storing more than a small fraction of the solar energy that falls onto their leaves. Those inefficiencies limit how fast trees and other plants grow, and how much carbon dioxide they soak up.
In 2019, Ort and his colleagues announced that they had genetically hacked tobacco plants to photosynthesize more efficiently. Normally, photosynthesis produces a toxic byproduct that a plant must dispose of, wasting energy. The Illinois researchers added genes from pumpkins and green algae to induce tobacco seedlings to instead recycle the toxins into more sugars, producing plants that grew nearly 40% larger.
That same year, Hall, who had been working for ventures like Open AI, met her future cofounder Patrick Mellor at a climate tech conference. With money raised from venture capital firms, she and Mellor started Living Carbon. Their scientists retooled Ort’s genetic hack for poplar trees and then produced engineered poplar clones that grew in pots. Last year, the company said in a paper yet to be peer reviewed that its tweaked poplars grew more than 50% faster than non-modified ones over five months in the greenhouse.
On the land of Vince Stanley, a seventh-generation farmer who manages more than 25,000 forested acres in Georgia’s pine belt, mattock-swinging workers carrying backpacks of seedlings planted nearly 5,000 modified poplars. The tweaked poplars had names like Kookaburra and Baboon, which indicated which “parent” tree they were cloned from, and were interspersed with a roughly equal number of unmodified trees.
In contrast to fast-growing pines, hardwoods that grow in bottomlands like these produce wood so slowly that a landowner might get only one harvest in a lifetime, Stanley said. He hopes Living Carbon’s “elite seedlings” will allow him to grow bottomland trees and make money faster. “We’re taking a timber rotation of 50 to 60 years and we’re cutting that in half,” he said. “It’s totally a win-win. ” To date, the only country where large numbers of genetically engineered trees are known to have been planted is China.