The entire eastern half of the United States was once blanketed by 4 billion chestnut trees that were suddenly wiped out by disease in the early 1900s. Here’s how a team of citizen scientists are bringing them back:
Chestnut trees once covered the entire eastern half of the United States, from Canada to Georgia.
They were a staple of the colonial economy and Native American diets for thousands of years.
And then, a little over a century ago, they were suddenly wiped out by a fungus imported along with Japanese chestnut trees.
There are more uses for American chestnut than for any other kind of tree, according to University of Tennessee biology professor Hill Craddock.
“European chestnut is one of the columns upon Western Civilization was built, ranking up there with the grapevine and olive tree as Mediterranean staples,” he adds in a Ted Talk titled The Return of the American Chestnut.
An acre of American chestnut trees can produce 2000-3000 pounds of delicious, protein-packed nutrition each year, and the nuts can be easily stored for long periods of time.
On top of the tons of nutritious nuts, chestnut trees made ideal lumber. It grew straight, tall and often branch-free for up to 50 feet. The high-quality, rot-resistant hardwood was once used for virtually everything until the Great Depression– telegraph poles, railroad ties, heavy construction, shingles, paneling, fine furniture and musical instruments.
Second only in size to the redwoods, they were the backbone of the eastern forests. Mature chestnuts are well over 100 feet tall and up to 10 feet in diameter and can live over a thousand years.
Chestnut trees also provided habitat for countless animal species. Bear, deer, wild turkey, squirrels, many birds and small mammals – and the once huge flocks of carrier pigeons – all depended extensively on them. The wildlife in turn, provided game meat for hunters.
Additionally, they served as a host for “choice edible fungi” including chanterelles and porcini mushrooms,” Craddock says.
And last but not least, chestnut trees helped make agriculture more sustainable.
“Agriculture causes environmental degradation, especially when it depends on the plow to plant annual crops,” Craddock says.
Perennial trees help mitigate the negative impacts of agriculture including soil erosion and loss of biological diviersity, “and the chestnut tree is the archetypal perennial tree,” he says
It anchors soil to the steepest of slopes, “intercepts rainfall and moderates the local climate by shading the under-story and transpiring water into the atmosphere.”
In these ways, chestnut groves supported entire local economies. But that beautiful way of life came to an end in 1904, with the discovery of chestnut blight in New York City.
The blight was caused by a fungus, an orange mold, that eats the bark of the tree and kills it. The fungus was brought in on the trunks of imported Japanese chestnut trees.
By 1950, the American chestnut had virtually disappeared from eastern forests.
Craddock blames agricultural revolutions, changing diets and changing economies, as well as the fungus, for the near worldwide extinction of chestnuts.
But there’s still hope, he says. The roots of many chestnuts are still alive. The soil bacteria has protected them from the fungus. Sprouts continue to spring up from the base, but they rarely grow large enough to flower and produce a seed.
Craddock is working with a group of citizen scientists called the American Chestnut Foundation to restore the beloved tree.
By a complicated process of crossbreeding the American chestnut with Asian chestnuts, they are developing a hybrid species that is resistant to chestnut blight and Phytophthora root rot, another disease the trees are facing.
They grow the hybrids in experimental orchards for several years before infecting them with a lethal dose of the dreaded fungus.
Most of the trees die. The value of the few remaining trees is priceless, Craddock says.
Only the most resistant individuals are advanced to the next generation.
“For the first time in history, with the help of private landowners and the U.S. Forest Service, we are currently testing blight resistant American chestnut trees that are between 94% and 97% American,” Craddock says.
“Chestnut trees are being planted all over the world, both where chestnuts grew traditionally and in new areas.”
Craddock says he is “very optimistic” about the return of the American chestnut and “confident that future generations will be able to enjoy this magnificent tree once again.”
However, he warns “ecological restoration is a very ambitious, very long-term goal,” one that could take 100 years. You can help speed the process along by donating to The American Chestnut Foundation.