Although many Americans still associate the winter holidays with chestnuts, the tree that once produced them – the American chestnut – no longer does, except in rare cases. During the first half of the 20th century, billions of chestnut trees died due to an exotic fungus, which was introduced into this country on Japanese chestnut. The loss of the American chestnut was a historic event, as the trees provided not only nuts, but also timber for the construction of houses, caskets and furniture, and the raw material for making railroad ties, shingles, telephone poles, fences and leather tannins.
In the 21st century, there are those who believe that trees can be resurrected via genetic engineering (GE). In fact, the United States Department of Agriculture (USDA) has just released a draft environmental impact statement and draft pest risk assessment that will allow the unrestricted planting of genetically modified blight-tolerant chestnut trees on land. public and private. If approved, the tree would be the first genetically modified plant released with the aim of spreading freely in the wild. Although the agency recommends releasing the tree into wild forests, it is also seeking public input regarding its recent decision to do so. (You can submit comments here.)
Restoration of the American Chestnut is a noble undertaking that certainly deserves our serious consideration and thoughtful deliberation. If the plan is successfully implemented, the tree would improve forest health, increase biodiversity and provide significant economic benefits to local communities. However, as an environmental historian, I am deeply concerned that those who endorse the unregulated status of the GM chestnut tree have not educated themselves sufficiently about the potential problems associated with genetically modified trees.
First, trees are complex organisms that interact with other living things over many growing seasons, even centuries. For this reason, more research is needed if we are to fully understand the impact of genetically modified chestnuts on larger forest ecosystems. Since Castanea dentata emerged on the planet 40 million years ago, humans have interacted with trees for 11 millennia but only studied the fungus Cryphonectria for a single century. The assumption that GM chestnuts will behave in a specific and predictable way, based only on a decade of research, is premature, if not wrong.
Indeed, studies have shown that the genomic structure of transgenic plants can mutate following gene insertion events and exhibit unexpected traits after reproduction. It is also possible that genetically modified chestnuts, as they age and grow, may not be able to repel blight, particularly if the enzyme OxO, produced by a wheat gene inserted into the chestnut’s DNA from America, becomes less prevalent in mature trees. . Scientists must be able to predict the future results of their experiments and cannot do so reliably in the case of genetically modified chestnuts.
As cliché as it may be to assert that those who don’t learn the past are doomed to repeat it, in the case of the American Chestnut, that could very well be true. Chestnut restoration is an honorable business, but the process should be done as carefully as possible, without harming the genomic heritage of this iconic tree. A wiser approach would be to adopt what the United Nations calls the “precautionary principle”, which limits actions that can permanently harm a species or ecosystem, especially if there is no certainty absolute as to their safety.
Although the large-scale cultivation and planting of American-Chinese hybrids is unlikely to be prohibited under the principle’s guidelines, transgenic chestnuts do not currently meet this threshold.
Obviously, the best option moving forward would be to have Castanea dentata thriving again in the eastern hardwood forest of the United States, because it is this tree, and no others, that has shaped the human and natural communities of North America.
Donald Edward Davis is a part-time researcher for the Harvard Forest, and a founding member of the Georgian Chapter of the American Chestnut Foundation. A former Fulbright Scholar, he is the author or editor of seven books, including “The American Chestnut: An Environmental Story.”
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