Opinion polls might matter as much as genetic experiments in protecting America’s trees, according to a new study of biotechnology and forest health.
“We struggled with that a lot, and didn’t come up with an answer,” said Diana Six, a University of Montana tree pathology researcher and co-author of the national study. “There are a lot of people who don’t want to see genetically modified natural forests. It will affect their lives and how they interact with the forest. Is wilderness still wilderness if the trees are all human products?”
But there are lots of tree species at risk of dying, and people value them for timber, shade, fruit, scenery and many other things. New lab techniques of gene editing, gene silencing, and controlled genetic mutation hold promise of blocking pests like insects, fungi and disease. Letting those modifications loose in the wild raises lots of unknown ecological and ethical questions.
So the U.S. Forest Service, Environmental Protection Agency and other policy makers asked the National Academies of Sciences, Engineering and Medicine to produce a “consensus study” showing how trees might be protected through genetic engineering.
Forests cover nearly a third of the continental United States: a million square miles of trees. Forest Service analyses predict the hardest-hit forests, covering 81.3 million acres, risk losing at least a quarter of their trees between 2013 and 2027 to insects and disease. The study asked its experts to gather all the current information about biotechnology and forest health, and present recommendations.
“This is a highly controversial topic,” Six said. “We had a group with a philosopher and an ethics person, social scientists, forest ecologists, entomologists and population geneticists. It’s not a quick fix.”
Six recalled a conference where someone asked why we can’t simply use gene-editing techniques like CRISPR to destroy pests. In addition to being an extremely complex laboratory challenge, Six said there are ethical problems to solve. We might agree it’s OK to genetically wipe out an invasive bug like the emerald ash borer. But the mountain pine beetle is a natural part of North American forests. Can we use the same biotechnology on it? And what if either project has unintended side effects?
For example, a national debate erupted in 1987 when Montana State University plant pathologist Gary Strobel injected a test grove of elm trees with a genetically altered bacteria intended to protect them from Dutch elm disease. He did so before receiving EPA approval for the experiment, resulting in a reprimand and sanction from the agency.
According to a New York Times story after Strobel personally cut down his trees to stop the experiment, the public was “uneasy about some aspects of biotechnology, particularly the potential dangers of releasing an altered microbe into the environment.” However, a competing research team in Holland completed the same experiment.
The new study had several poignant examples for its origin. The American chestnut tree used to number in the billions in the East before introduced blight and root rot pathogens nearly wiped it out in the early 20th century. Much more recently, the invasive emerald ash borer beetle has walloped urban forests. And Montanans like Six are familiar with the plight of whitebark pine trees, which nearly succumbed to an invasive blister rust fungus as well as infestations of native mountain pine bark beetles.
The study concluded that common methods of detection and eradication of pests were the best first course of defense for the nation’s forests. Using biotechnology has promise, but has to overcome a number of obstacles first.
Biggest among those is the overall big-ness of trees. Getting a single whitebark pine tree to reproduce itself takes almost 60 years, so the time frame of a multi-generation breeding study of effectiveness will take centuries. Pests typically attack multiple parts of a tree, so pinpointing which genes need reinforcement or modification quickly gets complex. And trees have widespread effects on their surrounding environment, from providing nuts for squirrels to shading snowbanks that provide late-summer water supplies.
Then there are the social aspects. What happens if a forest in the United States gets treated with a genetically modified agent, and its pollen drifts across the border into a Canadian forest?
“We heard quite a lot of resistance from Native American groups,” Six said. “They don’t see trees as Western cultures do, but as parts of their communities. If you change those organisms, they’re not the same. And indigenous communities don’t have large numbers of votes.”
As of 2018, only American chestnuts and hybrid poplar trees have been subject to biotechnological modifications on a field-trial scale. The study specifically did not explore using biotechnology against the pests attacking the trees.
The 217-page report goes to the White House, Congress, federal agencies and research organizations. From there, it becomes the National Academies’ official stance on the topic of biotechnology and forest health.
“It’s the go-to document for all those agencies,” Six said. “They tend to get a lot of heavy use by Congress for writing bills.”