On Monday, in a lower stretch of the southern Georgia pine belt, half a dozen workers planted row upon row of twiglike cottonwoods.
These weren’t just any trees, however: some of the seedlings nestling in the soggy soil had been genetically modified to produce wood at an accelerated rate while absorbing 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 commercial fruit orchard. Just as the introduction of the Flavr Savr tomato in 1994 ushered in a new industry of genetically modified food crops, tree planters on Monday hope to transform forestry.
Living Carbon, a San Francisco-based biotech company that produced the poplars, intends its trees to be a large-scale solution to climate change.
“Some people have told us it’s impossible,” Maddie Hall, the company’s co-founder and chief executive, said of her dream of implementing genetic engineering in the name of climate. But she and her colleagues have also found believers, enough to invest $36 million in the four-year venture.
The company has also drawn criticism. The Global Justice Ecology Project, an environmental group, has called The company’s trees are “growing threats” to forests and they 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 not yet published peer-reviewed articles; its only publicly reported results come from a greenhouse trial that lasted only a few months. These data have some experts intrigued, but they do not reach a complete endorsement.
“They have some encouraging results,” said Donald Ort, a University of Illinois geneticist whose plant experiments helped inspire Living Carbon’s technology. But he added that the notion that the results of the greenhouse effect will translate into success in the real world “is not a piece of cake.”
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Living Carbon’s aspens begin their lives in a laboratory in Hayward, California. There, biologists study how trees carry out photosynthesis, the series of chemical reactions plants use to convert sunlight, water and carbon dioxide into sugars and starches. In doing so, they follow a precedent set by evolution: Several times throughout Earth’s long history, improvements in photosynthesis have allowed plants to ingest enough carbon dioxide to substantially cool the planet.
While photosynthesis has a profound impact on Earth, 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 on their leaves. Those inefficiencies, among other factors, limit how fast trees and other plants grow, and how much carbon dioxide they absorb.
Scientists have spent decades trying to pick up where evolution left off. In 2019, Dr. Ort and his colleagues announced that they had genetically hacked tobacco plants to make photosynthesis more efficiently. Normally, photosynthesis produces a toxic byproduct that a plant must dispose of, wasting energy. The Illinois researchers added genes from gourds and green algae to induce tobacco seedlings to recycle the toxins into more sugars, producing plants that grew nearly 40 percent larger.
That same year, Ms. Hall, who had been working for Silicon Valley companies such as OpenAI (responsible for the language model ChatGPT), he met his future co-founder Patrick Mellor at a climate technology conference. Mr. Mellor was investigating whether trees could be engineered to produce decay-resistant wood.
With money raised from venture capital firms and Hall’s tech contacts, including OpenAI CEO Sam Altman, she and Mellor started Living Carbon in a bid to stimulate trees to combat climate change. “There were so few companies looking at large-scale carbon removal in a way that combined cutting-edge science and large-scale commercial deployment,” Ms Hall said.
They recruited Yumin Tao, a synthetic biologist who had previously worked at the DuPont chemical company. He and others modified Dr. Ort’s genetic trick for poplars. Living Carbon then produced modified poplar clones and grew them in pots. Last year the company reported in a paper that has not yet been peer-reviewed that their modified poplars grew more than 50 percent faster than their unmodified ones over five months in the greenhouse.
The company researchers created the trees tested in a greenhouse using a bacterium that splices foreign DNA into the genome of another organism. But for the trees they planted in Georgia, they turned to an older, cruder technique known as the gene gun method, which essentially shoots foreign genes into the trees’ chromosomes.
In a field accustomed to advancing glaciers and strong regulation, Living Carbon has moved quickly and freely. The GM poplars avoided a set of federal GMO regulations that can bog down biotech projects for years. (Those regulations have since been revised.) By contrast, a team of scientists who genetically engineered a blight-resistant chestnut tree using the same bacterial method previously employed by Living Carbon has been waiting for a decision since 2020. An engineered apple grown on a small scale in Washington state took several years. in being approved.
“You could say the old rule had some leaks,” said Bill Doley, a consultant who helped manage the Department of Agriculture’s GMO regulation process through 2022.
On Monday, on the land of Vince Stanley, a seventh-generation farmer who manages more than 25,000 wooded acres in the Georgia pine belt, hoe-swinging workers carrying backpacks of seedlings planted nearly 5,000 modified cottonwoods. The modified poplars had names like Kookaburra and Baboon, indicating which “parent” tree they were cloned from, and were intercropped with a roughly equal number of unmodified trees. By the end of the unseasonably warm day, workers were drenched in sweat and planting plots were dotted with pencil-thin seedlings and colorful flags poking out of the mud.
In contrast to fast-growing pines, lowland-growing hardwoods like these produce wood so slowly that a landowner might get only one crop in his lifetime, Stanley said. He hopes Living Carbon’s “elite seedlings” will allow him to grow trees in the lowlands and earn money faster. “We’re taking a 50 to 60 year wood rotation and cutting it in half,” he said. “It’s totally a win-win.”
Forest geneticists were less optimistic about the Living Carbon trees. Researchers typically evaluate the trees in confined field trials before moving on to large-scale plantings, said Andrew Newhouse, who directs the engineered chestnut project in SUNY’s College of Environmental Sciences and Forestry. “Their claims seem bold based on very limited real-world data,” he said.
Steve Strauss, a geneticist at Oregon State University, agreed with the need to look at the field data. “My experience over the years is that the greenhouse means almost nothing” about the outdoor prospects of trees whose physiology has been modified, he said. “Venture capitalists may not know that.”
Dr. Strauss, who was previously on Living Carbon’s advisory board, has been growing some of the company’s seedlings since last year as part of a company-funded field trial. He said the trees were growing well, but it was still too early to tell if they were outgrowing the unmodified trees.
Even if they do, Living Carbon will face other challenges unrelated to biology. Although the total destruction of genetically modified trees has decreased thanks in part to stricter enforcement of the laws against acts of ecoterrorism, the trees still cause concern in the forestry and environmental world. The major organizations that certify sustainable forests ban GM trees from forests that win their approval; some also prohibit member companies from planting modified trees anywhere. To date, the only country where large numbers of GM trees are known to have been planted is China.
The US Forest Service, which plants a large number of trees each year, has said little about whether it would use modified trees. To be considered for planting on national forests, which make up nearly one-fifth of US forest land, Living Carbon trees would need to align with existing management plans that generally prioritize forest health and diversity over reducing the amount of atmospheric carbon, said Dana Nelson, a geneticist with the service. “I find it hard to imagine that it would fit well in a national forest,” said Dr. Nelson.
Living Carbon is focusing for now on private land, where it will face fewer obstacles. Later this spring, he will plant cottonwood trees in abandoned coal mines in Pennsylvania. By the next year, Ms. Hall and Mr. Mellor hope to plant millions of trees in the ground.
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To produce a revenue stream that doesn’t rely on venture capital, the company has begun marketing carbon-based credits that will soak up its trees. But carbon credits have come under fire lately and the future of that industry is in doubt.
And to avoid environmental concerns, Living Carbon’s modified poplars are all female, so they won’t produce pollen. While they could be pollinated by wild trees and produce seed, Mellor says it’s unlikely they’ll spread into the wild because they don’t breed with the more common cottonwood species in the Southeast.
They are also being planted alongside native trees such as sweetgum, tulip and bald cypress, to avoid groups of genetically identical trees known as monocultures; unengineered poplars are being planted as experimental controls. Ms. Hall and Mr. Mellor describe their plantings as pilot projects and research trials. The company’s scientists will monitor the growth and survival of the trees.
Such measures are unlikely to appease opponents of genetically modified organisms. Last spring, the Global Justice Ecology Project argued that Living Carbon’s trees could harm the climate by “interfering with efforts to protect and regenerate forests.”
“I am very surprised that they are moving so quickly” to plant a large number of engineered trees in the wild, said Anne Petermann, the organization’s executive director. The potential risks to the larger ecosystem needed to be better understood, she said.
Dr. Ort of the University of Illinois dismissed such environmental concerns. But he said investors were taking too much risk with a tree that might not live up to its creators’ expectations.
“It’s not boring,” he said. “I just think it’s super high risk.”
Audra Melton contributed reporting from Georgia.
