In a low-lying stretch of Georgia’s southern pine belt Monday, six workers planted row after row of twiggy aspen trees.
These aren’t just ordinary trees, though: some seedlings growing in moist soil have been genetically modified to grow wood at turbocharged speeds while absorbing carbon dioxide from the air.
Poplars may be the first genetically modified trees to be planted in the United States outside of research trials or commercial orchards. Just as the introduction of the Flavr Savr tomato in 1994 ushered in a new industry of genetically modified food crops, Monday’s tree planters hope to transform forestry.
Living Carbon, the San Francisco-based biotech company that produced the poplars, intends to make its trees a large-scale solution to climate change.
βWe were told it was impossible,β Maddie Hall, the companyβs co-founder and CEO, said of her dream of deploying genetic engineering for the climate. But she and her colleagues have also found believers β enough to invest $36 million in the four-year-old company.
The company has also drawn criticism. Environmental organization Global Justice Ecology Project, already called The company’s trees posed an “increasing threat” to forests and expressed alarm that the federal government had allowed them to evade regulation, opening the door to commercial cultivation earlier than typical engineered plants.
Living Carbon has yet to publish a peer-reviewed paper; its only publicly reported results come from a greenhouse experiment that lasted only a few months. These figures have intrigued some experts, but are far from being fully endorsed.
“They’ve had some encouraging results,” says University of Illinois geneticist Donald Ort, whose experiments with plants helped inspire Living Carbon’s technique. But the idea that the greenhouse effect will translate into real-world success is “not a slam dunk,” he added.
π³π³
Living Carbon’s poplar trees begin their lives in a laboratory in Hayward, California. There, biologists study how trees carry out photosynthesis, the series of chemical reactions that plants use to weave sunlight, water and carbon dioxide into sugars and starches. In doing so, they followed evolutionary precedent: Improvements in photosynthesis have repeatedly enabled plants to absorb enough carbon dioxide to significantly cool the planet over Earth’s long history.
While photosynthesis has profound effects on Earth, as a chemical process it is far from perfect. Many inefficiencies prevent plants from capturing and storing even a fraction of the solar energy that falls on their leaves. These inefficiencies, among others, limit how quickly trees and other plants can 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 colleagues announced that, They genetically engineer tobacco plants to photosynthesize more efficientlyγ Normally, photosynthesis produces a toxic by-product that plants must dispose of, wasting energy. Researchers in Illinois added genes from squash and green algae to induce tobacco seedlings to convert toxins into more sugar, allowing the plants to grow nearly 40 percent larger.
In the same year, Ms. Hall, who has been working in Silicon Valley companies such as OpenAI (responsible for language models), Chat GPT), met her future co-founder, Patrick Mellor, at a climate tech conference. Mr Mailer is investigating whether trees can be engineered to produce rot-resistant timber.
With funding from venture capital firms and Ms. Hall’s network in the tech world, including OpenAI CEO Sam Altman, she and Mr. Mailer started Living Carbon, which aims to juice trees to fight climate change. “Few companies are considering large-scale carbon removal in a way that combines cutting-edge science with large-scale commercial deployment,” Ms Hall said.
They hired Yumin Tao, a synthetic biologist who had worked at DuPont Chemical. He and others have adapted Dr. Ott’s poplar genetic hack. Living Carbon then grew the modified poplar clones and planted them in pots.Last year, the company Published in a paper that has not yet been peer-reviewed Over five months in the greenhouse, the adjusted poplars grew more than 50 percent faster than unmodified poplars.
Researchers at the company used a bacterium to splice foreign DNA into the genome of another organism, creating trees that were tested in greenhouses. But for the trees they planted in Georgia, they turned to an older, cruder technique called the gene gun method, which essentially injects foreign genes into the trees’ chromosomes.
In a space accustomed to slow development and strict regulation, Living Carbon’s development was fast and free. Biogun-engineered poplar avoids a set of federal regulations restricting genetically modified organisms that could stall biotech projects for years. (Those rules were later revised.) By contrast, a team of scientists genetically engineered a chestnut tree to resist blight using the same bacterial approach Living Carbon had earlier adopted, and has been awaiting a decision since 2020. . Washington State’s scale would take several years to be approved.
“You could say the old rules were a little bit loopy,” said Beardowley, a consultant who helps manage the Department of Agriculture’s GMO regulatory process through 2022.
On Monday, pickaxe-wielding workers with backpacks planted nearly 5,000 improved poplar trees on the property of Vince Stanley, a seventh-generation farmer who manages more than 25,000 acres of forest in Georgia’s pine belt. The adjusted poplars had names like kookaburra and baboon, indicating which “parent” tree they were cloned from, and were interspersed with roughly equal numbers of unmodified trees. Workers were sweating by the end of an unseasonably warm day, and the plantings were dotted with pencil-thin seedlings and colored marker flags poking out of the dirt.
Compared with the fast-growing pines, the hardwoods that grow in these depressions produce wood so slowly that landowners may only harvest it once in a lifetime, Mr Stanley said. He hopes Living Carbon’s “elite seedlings” will allow him to grow swale trees and make money faster. βOur timber rotation is 50 to 60 years and we are cutting that in half,β he said. “It’s totally a win-win.”
Forest geneticists are less optimistic about Living Carbon’s trees. Researchers typically evaluate trees in limited field trials before moving to large-scale plantings, said Andrew Newhouse, director of the Chestnut Engineering Program at SUNY College of Environmental Science and Forestry. “Based on very limited real-world data, their claims seem bold,” he said.
Oregon State University geneticist Steve Strauss agrees with the need to look at field data. “My experience over the years is that greenhouses are pretty much useless for the outdoor prospects of trees whose physiology has been altered,” he says. “Venture capitalists may not know this.”
Dr Strauss, who previously served on Living Carbon’s advisory board, has planted some of the company’s seedlings since last year as part of field trials funded by the company. He said the trees were growing well, but it was too early to tell whether they outperformed unmodified trees.
Even if they do, Living Carbon will face other challenges that have nothing to do with biology. While the outright destruction of GM trees has declined, in part because of tougher law enforcement against acts of ecoterrorism, the trees still cause unease in forestry and environmental circles. The major organizations that certify sustainable forests prohibit the planting of engineered trees from the forests they approve; some also prohibit member companies from planting artificial trees anywhere. To date, the only country known to have planted significant numbers of GM trees is China.
The U.S. Forest Service, which plants large numbers of trees each year, has said little about whether engineered trees will be used. To be considered for planting Living Carbon’s trees in national forests that account for nearly one-fifth of U.S. woodland, they need to be consistent with existing management plans that often prioritize forest health and diversity over reducing atmospheric carbon content, says Dana Nelson, serving geneticist. “It’s hard for me to imagine it would be a good fit for a national forest,” Dr. Nelson said.
Living Carbon is currently focusing on private land, where it will face fewer obstacles. Later this spring, it will plant poplars on abandoned coal mines in Pennsylvania. By next year, Ms Hall and Mr Mellor hope to have millions of trees in the ground.
π³π³π³
To generate a revenue stream not dependent on venture capital, the company has begun marketing credits based on the carbon its trees absorb.but Carbon credits have come under fire recently The future of the industry is in doubt.
To avoid environmental concerns, Living Carbon’s modified poplar trees are all female so they don’t produce pollen. While they can be pollinated and produce seeds by wild trees, Mr Mellor said they were unlikely to spread into the wild because they do not breed with the poplar species most common in the southeast.
They are also being planted next to native trees such as sweet gum, tulip tree and bald cypress to avoid being called monocultures of genetically identical trees; non-engineered poplars are being grown as experimental controls. Ms Hall and Mr Mailer described their planting as a pilot project and research trial. Company scientists will monitor the growth and survival of the trees.
Such measures are unlikely to appease opponents of GMOs. Last spring, the Ecological Project for Global Justice argued that Living Carbon’s trees could harm the climate by “interfering with efforts to protect and regenerate forests.”
“I’m absolutely shocked by how quickly they’ve moved,” said Anne Petermann, the group’s executive director, planting vast numbers of improved trees in the wild. A better understanding of the potential risks to the larger ecosystem is needed, she said.
Dr. Ott of the University of Illinois dismisses such environmental concerns. But he said investors were taking a big risk on a tree that might not live up to its creators’ expectations.
“It’s not exciting,” he said. “I just think it’s super high risk.”
Audra Melton contributed reporting from Georgia.
