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July/August 2024

Time for transgenic trees?

Thomas Parker Redick


  • In the article below, we review the current challenges facing transgenic trees, including Regulatory approval in the US (as well as overseas markets).
  • We will also review litigation risks in the US, which can include economic risks to “NonGMO” tree products and export-related risks.
Time for transgenic trees?
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This article reviews the issues arising from the marketing of transgenic or genetically modified trees. Such trees are in the process of development, but face opposition from anti-biotechnology activists. Litigation under the National Environmental Policy Act (NEPA) can await any transgenic tree approved by the federal government without adequate review of risks, including both environmental and economic risks. Mass tort actions have followed other biotech crops (corn, wheat, and rice, for example) and that risk also looms over transgenic trees. New forms of plant breeding involving genetic editing could make the breeding of transgenic trees even easier.

Trees may need biotech to beat pests

For three years, I served as pro bono counsel to the U.S. Department of Agriculture (USDA) Forest Health Initiative, which addressed the potential use of biotechnology in tree breeding. Trees that could be addressed under this program included the Hemlock, which has the wooly adelgid pest, the American Chestnut, which blight killed off nearly completely, the Dutch Elm Disease afflicting many an elm alongside the avenues of U.S. towns, and the Ash tree, which is under attack from the emerald ash borer. Pines are also under threat from various pests and could benefit from innovation in biotechnology.

The biomass revolution in power generation, as one form of alternative fuel, also offers a market for biotechnology in tree breeding.

Given all the threats our trees face, any and all tools for saving them should be used.

Trees enter a crowed crop marketplace

Around the world, transgenic, genetically modified organisms (GMO), or biotech crops have been grown for food in 31 countries and for feed in 19 countries. The most commonly incorporated trait is herbicide tolerance (HT; e.g., crop tolerance to glyphosate and glufosinate), followed by insect resistance (IR; e.g., crops containing genes that produce insecticidal proteins derived from the soil bacterium Bacillus thuringiensis (Bt)) (Aldemita et al., 2015), and some viral innovation (e.g., the papaya). Crops with stacked traits (i.e., several traits), are increasingly used, particularly in corn (maize with 30 percent of the total trait approvals).

As of 2023, for example, the U.S. Animal and Plant Health Inspection Service (APHIS) had approved petitions for various transgenic crops including, in order of varieties approved, maize, cotton, tomatoes, soybeans, rapeseed/canola, potatoes, sugar beets, papaya, rice, summer squash, alfalfa, plum, rose, tobacco, flax, and chicory.

Adoption of genetically engineered crops in the United States, 1996-2023. Percent of planted crop acres for each crop

Graph Source: USDA, Economic Research Service using data from the 2002 ERS report, Adoption of Bioengineered Crops (AER-810) for 1996–99 and National Agricultural Statistics Service, (annual) June Agricultural Survey for 2000–23. Note: HT indicates herbicide-tolerant varieties; Bt (Bacillus thuringiensis) indicates insect-resistant varieties (containing genes from the soil bacterium Bt). Data for HT/Bt corn and cotton are not mutually exclusive, as HT and Bt categories include those varieties with overlapping (stacked) HT and Bt traits.

Adoption of genetically engineered crops in the United States, 1996-2023. Percent of planted crop acres for each crop

The following table shows the rapid adoption of biotech crops in the three row crops of corn, soy, and cotton.

In the United States, major field crops use either pest or herbicide resistance traits, including soy (94 percent), maize (89 percent), and cotton (89 percent), covering about half of the total cropland. Most maize (77 percent) and cotton (79 percent) have stacked herbicide‐tolerant and insect‐resistant traits.

Increasing numbers of reports of herbicide resistance in weeds and insect pest resistance to Bt crops make it very clear that more comprehensive risk assessments over longer temporal and larger spatial scales may be needed. Other crops with viral traits, like the papaya, require assessments that account for different types of potential environmental effects beyond those associated with herbicide and pest resistance.

The USDA is actively promoting biomass for energy in 2024, noting the potential for trees as well as switchgrass and hemp in creating high volume biomass.

Time for transgenic trees?

Trees cover more than 30 percent of the land biosphere and play an essential part in our lives by photosynthesizing, cleaning the air, and contributing to the beauty of landscapes. They are also a major source of fuel and processed products. Technologies for speeding up tree breeding using genetic editing have recently arrived. Such technologies could include modifying wood composition and structure, manipulating growth and development, improving pest or disease resistance, and landscape restoration.

Biotech innovation is a promising approach to speeding up tree breeding. Traditional tree breeding identified mature tree traits, but breeding programs took 20 years or more for trees to reach reproductive maturity with no guarantee that the desired trait will take. Biotechnology can overcome many of the drawbacks of conventional breeding.

Given the push for biomass, fast-growing eucalyptus may be needed. Aborgen’s transgenic eucalyptus, a rapidly growing Australian tree, is a dominant player in the tropical timber industry. International Paper Company and MeadWestvaco Corporation are industry giants planning to transform plantation forests in the southeastern United States. Their joint biotech venture, ArborGen LLC, aims to replace native pine with genetically engineered eucalyptus trees. These trees are designed to resist freezing temperatures. They also have a gene restricting the trees’ ability to reproduce, which prevents any unwanted spread or invasive aspect.

Two species from the genus Agrobacterium (A. tumefaciens and A. rhizogenes) have been used for gene transfer into trees. Agrobacterium rhizogenes, responsible for hairy root disease, transfers genes from an Ri, or root-inducing, plasmid. A feature of this disease is the formation of profuse, fluffy white roots at the site of inoculation. This enhanced rooting may be of value for urban trees in helping establishment.

Trees regenerated from hairy roots are frequently dwarf in stature, often with reduced internode distance and pronounced leaf wrinkling. Such trees may be attractive for streetscape, park, or domestic garden situations and may have occurred spontaneously in some plant species without human interference.

The iconic American Chestnut has been transformed via biotechnology and is also emerging from its USDA regulatory process in the coming year. It hit a snag in its choice of trees to use, since the trees are struggling as they get older, and they may need another set of genes in the next tree. Meanwhile, the traditional chestnut breeding program has a hybrid chestnut tree growing tall with good nuts at 15 years, so these traditional methods of plant breeding might be ahead of the game at this point. Given the long lead time required for traditional plant breeding methods, however, it is clearly the tortoise trying to beat the hare.

Litigation risks

The risk of NEPA litigation is the most immediate risk to the introduction of transgenic trees in the United States.

In 2010, activist attorneys from the Center for Biological Diversity filed a suit to stop the launch of Arborgen’s biotech eucalyptus, due to USDA’s alleged failure to properly assess the risks of this transgenic tree. In addition to risks of invasiveness, they alleged such trees excessively used water, increased fire risks, and could harbor a fungus that sickens people.

In 2022, the Biden administration restored NEPA to full strength after it was weakened by President Trump. This could increase the risk that NEPA will be used to stop the commercial launch of biotech trees. NEPA could enjoin future genetically edited trees, particularly if those trees do not trigger either USDA or EPA regulatory scrutiny. USDA has let other genetically edited crops in the row crop area be marketed.

Mass tort litigation poses a risk if undesirable economic effects arise, particularly from interference with exports of tree products. The American Chestnut was transformed via biotechnology and could generate delicious nuts that Americans might roast on an open fire as early as Christmas 2025. If it reaches the point of having a commercially marketable nut, and is grown widely, this could trigger an economic conflict with other sellers of chestnuts, which rely on European and Asian hybrids of American Chestnuts.

If unwanted commingling of genes meets certain legal standards, it could trigger litigation over the economic impacts of the biotech chestnut. Such impacts could arise from contamination with organic or non-GMO products, as well as exports of tree products to nations banning GMOs.

One of the main sources of chestnuts around Christmas time is the Whole Foods Market, which has taken a position that it will not sell GMO crops. As a result, it could have pollen drift from biotech chestnuts to its own growers, causing nuts unsuitable for marketing in Whole Foods Markets.

Whether for biomass, tasty nuts, or other benefits, biotechnology-bred trees will be coming to America soon. They face litigation risks that can be managed through careful stewardship, and such risks will need to be managed if biotech trees are to reach their full potential.