Freinkel, Susan. American Chestnut: The Life, Death, and Rebirth of a Perfect Tree. Berkeley: U of California P, 2007.
Freinkel chronicles the history of the American chestnut tree in the 20th century and through that history, explores arguments about native species restoration, federal funding for scientific research, and bioengineering.
At the turn of the 20th century, the American chestnut had a near-ubiquitous range through the eastern United States and was a vital part of Appalachia’s ecology, culture and economy. The chestnut blight, a non-native fungus that probably came to the U.S. by way of imported Japanese chestnuts, caused a virtual extinction of the American chestnut tree by the middle of the century. Other species of chestnut – Chinese, Japanese, and European chestnuts – had some degree of natural resistance to the Cryphonectria parasitic fungus. The fungus’ spores could spread widely via wind and birds and quickly infiltrate even the smallest cracks in a chestnut tree’s bark. An infected chestnut tree developed lumpy, unsightly cankers as it tried to fight the fungus, but ultimately, the tree quickly dies.
Early efforts to contain the spread of the fungus by spraying trees, quarantining, or creating a dividing line in Pennsylvania between the infected eastern and the uninfected western part of the state did not work, and eventually, scientists and US Forest Service officials recommended cutting down all chestnuts, infected or not, as a way to prevent the spread of the disease. The fungus lived on in the root systems of chestnut trees, so that when young saplings sprouted from the stumps, they were quickly infected and died.
In the mid-century, scientists took a few different approaches to try to resurrect the American chestnut and make it more resistant to the fungus. The first approach was through plant breeding: Arthur Graves did controlled cross-breedings of American chestnuts with Japanese and Chinese chestnuts beginning in the 1930s, hoping that eventually the cross would create a hybrid that retained the American chestnut’s desirable qualities and add in fungus resistance. In the 1980s, the plant breeding approach took another step further through the American Chestnut Foundation’s backcross breeding program (promoted by Charles Burnham, Philip Rutter, and Fred Hebard), which resulted in a tree that was 15/16 American chestnut (and 1/16 Chinese chestnut). Another breeding approach started in the 1980s was to stay within the American chestnut species and attempt intercross breeding (this was promoted by Gary Griffin and the American Chestnut Cooperators’ Foundation.)
A second approach for restoring the American chestnut was through the fungus. Scientists discovered the phenomenon of “hypovirulence” by observing how a virus could cripple the fungus and leave it less able to kill off a chestnut. The virus would not completely destroy the fungus, but it would leave the fungus’ attack weak and thus give the chestnut a chance to fight the infection. Scientists (Sandra Anagnostakis) began inoculating infected and non-infected chestnut trees with that virus to help them fight of the fungus, hoping that the virus could be spread from tree to tree and result in a more widespread defense against the fungus.
A third approach is through bioengineering the American chestnut tree by altering the two to three genes on its DNA that control fungus resistance. Two scientists at SUNY ESF (Charles Maynard and William Powell) have been working on this problem and have successfully planted a half-dozen bioengineered American chestnuts on the SUNY ESF campus.
There is much debate about how to reintroduce the American chestnut into its natural eastern US range. When the chestnuts died off, they were overtaken by other trees, notable oaks, and so replanting the American chestnut would require cutting down mature trees. Some advocate planting the American chestnut on abandoned, ravished mountaintop mining sites. Others question whether the American chestnut, so carefully breeded or inoculated or bioengineered, has the ability to be reintroduced into the wild and survive.
“Practically speaking, of course, the tree’s salvation depends on scientific answers. Yet in the end, the daunting challenge of saving the species – or any species, for that matter – requires a marriage of science and passion. The American chestnut has been lucky enough to inspire such a marriage, though whether it proves to be enough to ultimately bring back the perfect tree remains an open question” (6).
“The comes the trickier issue of letting go: planting backcross chestnuts in the wild so the species may start the unpredictable process of going forward on its own. The hows, whens, wheres, and what-ifs of that process are sources of continuing debate” (212).
Problem – “Even if the hybrids do prove a desirable replacement for the original tree, some scientists have expressed concern that the perfect tree could be too perfect.” (213)
restoration and authenticity – “Just as a copy of the Mona Lisa, however perfect, will never be as valuable as the original, so even the most faithful restoration of a wild place cannot reproduce the value of the original wilderness, for that value lies in its intrinsically non-human nature, the fact that it exists free of human influence.” (218)
Robert Frost, “Evil Tendencies Cancel”
Will the blight end the chestnut?
The farmers rather guess not.
It keeps smouldering at the roots
And sending up new shoots
Till another parasite
Shall come to end the blight.
Is restoration – going back to an earlier ecosystem – a practical or possible effort? (218 and 219)
Leopold, A Sand Country Almanac
Phyllis Windle, “The Ecology of Grief”
USDA quarantine of imports of non-native species
bioengineering and plant breeding a wild tree, not a domesticated crop or a garden plant.
other tree blights: elm, sudden oak death. The death of the elm was more apparent, more publicly discussed because the elm was a city/town tree, and the chestnut was a country tree (3)
Patrick County, VA – lost all its chestnuts, destroyed the Appalachian community that lived there. Families depended on the chestnut harvest for food, to feed their livestock, and to harvest and trade for goods.
Chestnut trees – “the perfect tree” – were valuable for their nuts and their tall, straight, relatively rot-resistant wood.
Bronx Zoo, 1904 – first sight of the chestnut blight, completely destroyed chestnuts in the zoo by 1908.
A few chestnuts survived in the wild, including a stand in West Salem, Wisconsin (Chestnut Hill).