Under a spreading chestnut-tree
The village smithy stands...
– Henry Wadsworth Longfellow, 'The Village Blacksmith'
The American chestnut, Castanea dentata, is a mighty tree indeed: related to the European sweet chestnut, Castanea sativa, it once provided shade and mast1 for livestock throughout the Appalachian mountain range. Its wood was prized for the quality of its grain and its resistance to rot. American chestnuts, fast-growing trees of the beech family, provided shade for more than one village smithy and increased biodiversity in the Eastern Woodlands.
The Cherokee of the Appalachian mountains had many uses for the chestnut, from firewood and lumber supplies to a coffee substitute to medicinal teas and poultices. The chestnut contributed much to the forest canopy. Its spring blossom lent the Great Smokies their distinctive look. The chestnut is one of the reasons why tens of thousands of poor immigrants from Scotland, Ireland, and Germany flocked to the mountains every year in the 18th Century. But why are we talking about these magnificent trees in the past tense?
In the youth of a man not yet old, native Chestnut was still to be seen in glorious array – the great forest below waving with creamy white Chestnut blossoms in the crowns of the ancient trees, so that it looked like a sea with white combers plowing across its surface.
– Naturalist Donald Culross Peattie (1898-1964)
In the early 20th Century, an accidentally-imported blight devastated North America's chestnut population. It was an ecological disaster with far-reaching consequences. It impoverished the ecosystem and the farmers alike. In the 21st Century, efforts are being made to facilitate the comeback of this important tree. This is the story.
What Went Wrong
Before the chestnut blight, there was a popular saying that a squirrel could travel from chestnut tree to chestnut tree from New England to Georgia without touching the ground. It makes sense: an estimated 25% of the trees in the Appalachians were chestnuts. In the early 20th Century, this changed. The blight was caused by a bark fungus, Cryphonectria parasitica, carried by Asian chestnut trees imported for decorative purposes in the late 19th Century. The chestnut blight was first observed in the Bronx Zoo in New York City in 1904. The airborne fungus spread at the rate of 80 km a year, killing up to three billion trees within a few decades – and drastically changing the ecology of the Appalachians.
Mountain farmers lost the valuable mast for their livestock. They also lost a source of income, as they often collected the chestnuts for sale and sold the quality wood, as well as using it themselves. The need to grow more fodder for farm animals strained the already tenuous economies of subsistence farms. In addition, the ecosystem of the mountain range was negatively affected.
Other imported parasites damaged the chestnut population, as well: ink blight from Portuguese cork oak trees. Oak trees play host to these various fungi without damage, but the injury to the American chestnut was devastating. The spread of the Chinese gall wasp was another blow to the chestnut population. The chestnut's loss was hard-felt, and the tree appeared doomed.
What Is Being Done About It
The American Chestnut Foundation (TACF) is a non-profit organisation with a single goal: to restore the American chestnut to the ecosystem of the eastern North American forest. TACF was founded in 1983 by a group of plant scientists that included Norman Borlaug, a world-renowned scientist who won the Nobel Peace Prize in 1970 for his work in improving the world's food supply. TACF has spent years working on a genetic solution to the problem of chestnut blight.
Using the back-cross method already successfully demonstrated in maize by plant scientist Charles Burnham, the group has crossed American chestnuts with blight-resistant Asian chestnuts. The aim is to get a tree with the desirable qualities of an American chestnut, including the large, nutritious nuts, combined with the natural genetic resistance of the Asian variety. And it's working.
Although research is ongoing, resistant trees are already being planted within the tree's former range. To date, more than 22,000 trees have been planted in Pennsylvania alone. The Pennsylvania TACF chapter offers a handy planting manual as a guide. The US Department of Agriculture (USDA) supports the initiative and found it important enough to devote an entire issue of its journal Compass to the history, genetics, and future of the American chestnut.
Why This Is Important
Restoring the American chestnut could revive forests and support wildlife. American chestnut population can also help to check the undesirable spread of hemlock and rhododendrons, both of which are poisonous to animals and provide excessive cover that inhibits biodiversity.
In a world choking for lack of fresh air and clean water, any initiative that promises to restore a major ecosystem should be welcome. Trees make oxygen. They feed wildlife. They provide natural resources that do not require mining, quarrying, or otherwise damaging the landscape. Restoring the American chestnut is a win/win for humans and nature.
Want to read a book? Sign up at Internet Archive (it's free) and read American Chestnut: the Life, Death, and Rebirth of a Perfect Tree, by Susan Freinkel (Berkeley, 2007).
Visit TACF's website to learn more about their work.
Take a course and earn credit! The USDA offers an online course in the 'basic biology and silvics of the American chestnut and the factors that led to its demise.'