Modified Trees Raise Hope, and Concern
Recently, in a low-lying tract of southern Georgia’s pine belt, workers planted row upon row of twig-like poplar trees.
These were not just any trees, though: Some of the seedlings 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. Living Carbon, a San Francisco-based 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,” said Maddie Hall, the company’s co-founder. But she and her colleagues have also found believers, enough to invest $36 million in the fouryear-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 U.S. government allowed it to evade regulation, opening the door to commercial plantings much sooner than is typical for engineered plants.
Living Carbon’s poplars start in a lab in Hayward, California. There, biologists tinker with how to get the trees to photosynthesize more efficiently, allowing the trees to grow faster and soak up more carbon dioxide.
Last year, the company reported in a paper that has yet to be peer reviewed that its tweaked poplars grew more than 50 percent faster than non-modified ones over five months in a greenhouse.
On February 13, nearly 5,000 modified poplars were planted on the tract in Georgia. Vince Stanley, a farmer who manages the land, said hardwoods that grow in bottomlands like his produce wood so slowly that a landowner might get only one harvest in a lifetime. He hopes Living Carbon’s “elite seedlings” will allow him to grow 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.
Forest geneticists were less sanguine. Researchers typically assess trees in confined field trials before moving to large-scale plantings, said Andrew Newhouse, who directs the engineered chestnut project at the State University of New York. “Their claims seem bold based on very limited real-world data,” he said.
Living Carbon will face other challenges. Major organizations that certify sustainable forests ban engineered trees from forests that get their approval; some also prohibit member companies from planting engineered trees anywhere. The only country where large numbers of genetically engineered trees are known to have been planted is China.
Dana Nelson, a geneticist with the U.S. Forest Service, said that to be considered for planting in national forests, Living Carbon’s trees would need to align with management plans that typically prioritize forest health and diversity over reducing carbon.
Living Carbon is focusing for now on private land, where it will face fewer hurdles. This spring, it will plant poplars on abandoned coal mines in Pennsylvania. By next year, the company hopes to be putting millions of trees in the ground.
To head off environmental concerns, Living Carbon’s modified poplars are all female, so they will not produce pollen. While they could be pollinated by wild trees and produce seeds, they are unlikely to spread into the wild because they do not breed with the most common poplar species in the region, said Patrick Mellor, a company founder. They are also being planted alongside native trees to avoid genetically identical stands of trees known as monocultures.
Such measures are unlikely to assuage critics. 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’m very shocked that they’re moving so fast,” said Anne Petermann, the organization’s executive director.