Genetically modified trees are planted in the USA – 02/26/2023 – Environment

Last Monday (20), in a low ground in the pine belt of southern Georgia, half a dozen workers planted rows and rows of poplars that look like nothing more than twigs.

Not just any trees, though: some of the saplings placed in the soggy soil have been genetically engineered to produce wood at turbocharged rates while sucking carbon dioxide out of the air.

Poplars may be the first genetically modified trees planted in the United States outside of a research trial or commercial nursery. Just as the introduction of the Flavr Savr tomato in 1994 launched a new industry of genetically modified food crops, tree planters hope to transform forestry.

Living Carbon, the San Francisco-based biotechnology company that produced the seedlings, intends its poplar trees to be a large-scale solution to climate change.

“Some people have told us it’s impossible,” said Maddie Hall, the company’s co-founder and CEO, of her dream of using genetic engineering to improve the climate. But she and her colleagues also found enough believers to invest $36 million in the four-year company.

The company has also attracted critics. The environmental group Global Justice Ecology Project called the company’s trees a “growing threat” to forests and expressed concern that the federal government would allow the company to evade regulation, opening the door to commercial plantations much earlier than normal for modified plants.

Living Carbon has not yet published peer-reviewed articles; its only published results come from a greenhouse test that lasted only a few months. That data has some experts puzzled, but they’ve stopped short of a full endorsement.

“They have some encouraging results,” said Donald Ort, a geneticist at the University of Illinois whose plant experiments helped inspire Living Carbon’s technology. But he added that the idea that greenhouse results will translate into real-world success is not guaranteed.

Living Carbon poplar trees 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 transform sunlight, water and carbon dioxide into sugars and starches.

In doing so, they follow a precedent set by evolution: Several times throughout Earth’s history, improvements in photosynthesis allowed plants to ingest enough carbon dioxide to substantially cool the planet.

While photosynthesis has profound impacts 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. These 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, Ort and his colleagues announced that they had genetically modified tobacco plants to photosynthesize more efficiently. Normally, photosynthesis generates a toxic by-product that the plant has to dispose of, wasting energy. The Illinois researchers added genes from squash and green algae to trick the tobacco seedlings into recycling toxins into more sugars, producing plants that grew nearly 40% longer.

That same year, Hall, who worked for Silicon Valley ventures like OpenAI (responsible for the ChatGPT language model), met his future co-founder, Patrick Mellor, at a climate technology conference. Mellor was researching whether trees could be modified to produce rot-resistant wood.

With money raised from venture capital firms and Hall’s contacts in the tech world, including OpenAI CEO Sam Altman, she and Mellor founded Living Carbon, in an attempt to perfect trees to fight climate change.

“Few companies were looking at large-scale carbon removal in a way that combined cutting-edge science and large-scale commercial deployment,” said Hall.

In a field accustomed to slow progress and heavy regulation, Living Carbon moved quickly and freely. Gene-weapon-engineered cottonwoods have avoided a series of federal regulations on genetically modified organisms that can stall biotechnology projects for years. (These regulations have since been revised.)

By comparison, a team of scientists who genetically engineered a chestnut tree resistant to rust using the same bacterial method previously employed by Living Carbon has been waiting for a decision since 2020. A modified apple grown on a small scale in Washington state took several years to get approved.

“You could say the old rule was kind of buggy,” said Bill Doley, a consultant who helped manage the regulatory process for genetically modified organisms at the Department of Agriculture through 2022.

On Monday, on the land of Vince Stanley, a seventh-generation farmer who manages more than 10,000 hectares of forest in Georgia’s “pine belt,” workers carrying pickaxes and backpacks of seedlings planted nearly 5,000 modified cottonwood trees.

The modified poplars had names like Kookaburra and Baboon, indicating which “mother” tree they were cloned from, and were interspersed with approximately equal numbers of unmodified trees. At the end of the unseasonably hot day, the workers were drenched in sweat and the flowerbeds dotted with pencil-thin seedlings and colorful flags poking out of the mud.

In contrast to the fast-growing pines, the hardwoods that grow in lowlands like these produce wood so slowly that a farmer may only get one harvest in a lifetime, Stanley said. He hopes Living Carbon’s “elite seedlings” will allow him to grow lowland trees and make money faster.

“We are taking a forest rotation of 50 to 60 years and halving it,” he said. “It really is a win-win for everyone.”

Forest geneticists were less optimistic about Living Carbon’s trees. Researchers typically evaluate trees in confined field trials before moving to large-scale plantations, said Andrew Newhouse, who directs the modified chestnut project at the State University of New York’s College of Environmental Science and Forestry (SUNY).

“Their claims seem bold based on very limited real-world data,” he said.

Steve Strauss, a geneticist at Oregon State University, agrees with the need to see field data. “My experience over many years is that the nursery means next to nothing” about the outdoor prospects of trees whose physiology has been modified, he said. “Investors may not know this.”

The US Forest Service, which plants large numbers of trees each year, said little about whether it would use modified trees. To be considered for planting in national forests, which account for nearly one-fifth of the US’s forests, Living Carbon’s trees would need to align with existing management plans, which typically prioritize the health and diversity of forests over reducing the atmospheric carbon, said Dana Nelson, a geneticist at the service.

“I find it hard to imagine that it would fit well into a national forest,” said Nelson.

Living Carbon is focusing for now on private land, where it will face fewer obstacles. Later this spring, he will plant poplar trees in abandoned coal mines in Pennsylvania. Next year, Hall and Mellor hope to plant millions of trees in the ground.

_{Translated by Luiz Roberto M. Gonçalves}