Can Genetically Modified Trees Save American Forests?

By Richard Levine

Yesterday I attended the sixth North American Forest Insect Work Conference, a meeting that has been held every five years since 1991. This one is taking place in Washington, DC and ends on Friday, June 3, 2016. The meeting brings together regional forestry groups, including many from the USDA Forest Service, whom I estimate represent about 25 percent of the participants.

Richard Levine

Tom Tidwell, chief of the USDA Forest Service kicked off the event during his keynote address about why the work of forest entomologists and others is so important.

“Why should Americans care about healthy forests and grasslands?” he asked. “Well, if you don’t breathe air or drink water, then you shouldn’t care. But if you do breathe air and drink water, then you should. If you want clean air and water, you have to have healthy forests and grasslands.”

Forests also have recreational value for campers, hunters, and hikers, not to mention the economic value that is generated by these activities and the jobs that they create. Unfortunately, according to Dr. Tidwell, the threats posed by invasive insects and diseases will inevitably increase in the future due to increased international trade and climate change.

Unfortunately, the funding to manage these threats is decreasing, according to Monica Lear, director of Forest Health Protection at the USDA Forest Service. The proposed budget devoted to forest pests for 2017 is about $92 million, down from $104 million in 2014 and 2015.

Carlton Owen, the third plenary speaker and president of the U.S. Endowment for Forestry and Communities, believes that the answer could lie in biotechnology. Genetically modified trees that are resistant to viruses and other forest pests could help to restore tree populations, some of which have been decimated in recent decades.

For example, take the American chestnut tree, which used to be the dominant tree in the eastern United States. They were so big that they were sometimes called “the sequoias of the east.” The wood was excellent and could be used to make houses, railroad ties, and cabinets, and the edible nuts were eaten by people and fed to livestock.

But in the late 1800s these mighty trees began to disappear due to a fungus called Cryphonectria parasitica, which causes a disease called chestnut blight. Today, large, healthy American chestnut trees are rarely seen.

However, modern plant breeding techniques may help to restore American chestnuts and other trees in the near future, according to speakers at a symposium called “Off-the-shelf Kits for Saving the World’s Forests. Available Now!” The symposium, which was organized by University of Florida entomologist Jiri Hulcr and his PhD student Caroline Storer, discussed current and future technologies, how GMOs are currently regulated, and how the general public perceives them.

During a presentation called “Transgenic Blight-resistant American Chestnut Trees Demonstrate Potential for Restoring Threatened Species after Invasions by Exotic Pathogens,” Andrew Newhouse, a PhD student at SUNY-ESF, explained work that is being done on American chestnuts, eastern hemlocks, ash trees, walnut trees, and American elms.

Scientists determined that a gene found in wheat, called OxO, can enhance resistance to fungi. OxO, which is also found in bananas, strawberries, barley, and other plants was then introduced into the American chestnut, and, according to Newhouse, “IT WORKS!” Trees with the OxO gene that were first planted in 2006 are resistant to blight, and they do not require fungicides or other chemical treatments. Instead, the OxO gene works by producing an enzyme called oxalate oxidase that is found naturally in many food crops and is consumed by billions of people each day.

Newhouse also talked about the use of biotechnology in ash trees, tens of millions of which have been destroyed by an invasive beetle known as the emerald ash borer. Starting in the 1950s, a bacterium called Bacillus thuringiensis, or Bt, has been used by organic farmers as a natural insecticide. The Bt bacterium produces proteins that are toxic to certain insects, but are safe for human consumption, and for nearly 20 years farmers in the U.S. have grown corn, soybeans, cotton, and other crops that were modified to produce Bt proteins. The USDA Forest Service has also conducted research on Bt ash trees, and, according to Newhouse, some have shown resistance to emerald ash borers and to Japanese beetles.

While the scientists at the symposium were optimistic about the potential benefits these technologies hold, they also discussed regulatory and societal factors that may make them difficult to implement. Alison Adams, an environmental sociologist at the University of Florida, talked about “Public Trust in Science and Genetic Modification Technology,” and Adam Costanza, president of the Institute of Forest Biosciences, gave a presentation called “Biotech vs. Forest Pests: An Uneven Fight.” The opponent in his “uneven fight” was public perception, not forest pests, because of uncertainties about GMOs. The regulatory process is also burdensome, according to Costanza, because current regulations were developed 30 years ago, and the process takes a very long time and can be very expensive.

“In risk assessment, too much emphasis is put on ‘What might happen if we use a new technology?'” he said. “But we should also ask, ‘What will happen if we do not use it?'”

Read more at:

Reviving the American forest with the American chestnut: William Powell at TEDxDeExtinction

The American Chestnut Research and Restoration Project

New genetically engineered American chestnut will help restore the decimated, iconic tree

Transgenic American chestnuts show enhanced blight resistance and transmit the trait to T1 progeny

Development of transgenic North American ash trees expressing a Bacillus thuringiensis protein for management of the emerald ash borer


Richard Levine is Communications Program Manager at the Entomological Society of America and editor of the Entomology Today Blog.

Comments

  1. Paul Cherubini says:

    “Save American Forests” sounds overly sensational. Can the author actually specify the GPS coordinates of multiple areas of the USA that are permanently no longer forested because of invasive insects and/or climate change? Using these coordinates, readers could view these alledged areas on Google Earth.

  2. btremback says:

    Although I’m a proponent of using transgenic techniques to preserve our dwindling tree species, I would hope there would be some attention paid to the other species that might be adversely affected by something like a Bt ash tree. There are, after all, many species of butterflies and moths (150 just in the U.S. mid-Atlantic region, according to Tallamy) whose caterpillars feed on ash and in turn provide sustenance for birds, mammals, and predatory/parasitic insects.

  3. btremback, Andrew Newhouse said testing of non-targets is definitely required. Also, remember that some Bt proteins specifically target Coleoptera, not Leps. If you have other questions or concerns, please contact the USDA Forest Service: http://www.nrs.fs.fed.us/disturbance/invasive_species/eab/control_management/eab_resistent_ash/

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