A century ago the most dominant tree in the U.S., the American chestnut, towered over the land and ruled the East Coast forests from Georgia to Maine. Yet in as short a time as the span of a human life this majestic tree has not only disappeared, it has in many cases been forgotten.
Once upon a time, chestnuts grew all over North America and Eurasia, which was then joined to a supercontinent called Laurasia. Once Laurasia broke apart, seven species of chestnuts developed: Chinese, European, Japanese, dwarf Chinese, Chinese chinquapin, American chestnut and Allengheny chinquapin.
The trees belong to the genus Castanea and are a member of the beech family, which flourishes in the temperate zones across the northern hemisphere.
All species bear nuts that are high in fiber, protein, vitamin C and carbohydrates, while low in calories and fat.
All chestnuts have root systems that are able to regenerate new trunks; coppicing, as it is called, is a potent form of resilience against natural disturbances including landslides and flooding.
The native range of tall American chestnuts once spanned over 220 million acres as far west as Ohio, Kentucky and Tennessee. Their dominance lead to 1,094 places in the U.S. with chestnut in their name.
The American chestnut’s fruit was the sweetest of all of the species. The nuts are produced prodigiously, annually, with a single tree easily producing as many as 6,000 nuts. Those nuts fed bears, elk, squirrels, deer, raccoons, mice, wild turkeys — perhaps as many as 10 million, and supported enormous flocks of passenger pigeons.
Native Americans relished the chestnuts, using them for food as well as medicine, while families in the Southern Appalachians the 18th and 19th centuries depended heavily upon the chestnut crop for food and used it as a resource to trade for all other necessities.
The wood was even-grained, sandy colored and strong. By 1909, 600 million board feet of chestnut was cut annually. And by 1915, two-thirds of the tannic acid produced in the U.S. came from chestnut wood and bark.
Yet in the summer of 1904 the stately chestnuts at the New York Zoological Park began mysteriously to die.
The trees exhibited peppering of sun-colored spots, sunken patches of bark high over-head, handfuls of pale or withered leaves and lots of dying branches.
By the spring of 1905 every chestnut tree in the New York Zoological Park was infected.
Dr. William Murrill, a mycologist from Cornell University, discovered the life cycle of the fungus Cryphonectria parasitica or the chestnut blight. The fungus encircles the limbs or trunk and girdles or cuts-off the food and water supply. Within two or three years it kills a mature tree.
The blight likely came from a Japanese chestnut imported in the late 19th century, as the U.S. did not have a national quarantine system until 1912. While both Japanese and Chinese chestnuts were immune to the fungus, it was lethal for the American tree.
By 1911, Pennsylvania had mounted an all out campaign to eradicate the blight, but it was futile as the spores spread far and wide with even the slightest breeze.
In 1915 another imported destructive fungus Phytophethora cinnamomi attacked the roots of the American chestnuts.
By 1925 the chestnut blight had advanced deep into North Carolina, moving at as fast as 42 miles per year—lightening speed for a fungus.
At the height of the pandemic the U.S. Forest Service urged lumberman and landowners to cut down all of chestnut trees, dead or alive. How many resilient American chestnut trees were lost this way is anyone’s guess.
By 1943 some four billion American chestnut trees were dead, roughly enough to cover Yellowstone National Park 1,800 times over.
Today only about 300 resilient mature American chestnut trees remain as the species teeters on the edge of extinction.
Since the 1920s scientists have been attempting to breed Chinese and American chestnuts utilizing the Chinese genetic resistance to the fungus, while others are trying to develop a strain of fungus that attacks itself but not the tree. A third strategy that has been considered is using biotechnology to recombine the American chestnut genetics to provide resistance against the blight.
Even if these intrepid tree scientists succeed, reintroducing a species back into the wild is not without its challenges or its risks. Much of the basic ecology of the American chestnut is unrecorded and how it might cope with wildfire is speculative.
Yet in an era where humans are destroying 50,000 species a year—one every 10 minutes—re-establishing the American chestnut offers hope for making a difference as well as the opportunity to restore a magnificent ecosystem.
Dr. Reese Halter is a public speaker, conservation biologist and founder of the international conservation institute Global Forest Science. His latest book is “The Incomparable Honey Bee,” Rocky Mountain Books. He can be contacted through www.DrReese.com.