It’s sad, but much of today’s news contains stories about the endangerment or extinction of a plant or animal, or even an outright environmental catastrophe. Contrary to that trend, when I recently stumbled on an article about efforts to restore the endangered American chestnut tree to a place of importance in our forests, I immediately thought,
“This is a story Southern gardeners will appreciate, because they well know about the loss of much of the South’s longleaf pine population and other species due to over harvesting or disease.” The chestnut story seemed, at first, to be a simple “good news” report with a “lived happily ever after” ending. I soon learned, although a happy ending indeed seems possible, the end is still years in the future. So, this article is presented as a brief history of the American chestnut, and as an update on and praise for the work of dedicated researchers who are faced with many complications and frustrations in their efforts to restore it once again to prominence in our forests.
Prior to 1900, the American chestnut tree was the dominant species in forests from Maine to Georgia and Alabama. Because of its size and rugged trunk, it was often called the “Redwood of the East.” One of every four trees in Appalachian forests was a chestnut, and it was said to be “the most useful tree in the forest.” Its leaves were thought to have medicinal value – the “Chestnuts Roasting over an Open Fire” that we hear about in song at Christmas provided an abundance of food for wildlife and a valuable crop for farmers. Its strong, rot–resistant wood was used for furniture, fences, utility poles and building material. It was also a source of tannin used in curing leather, and it was valued and impressive in many landscapes.
Enter the Bad News
In 1904, the Bronx Zoo in New York noticed a blight affecting many chestnut trees that lined the roads in the zoo. The disease caused wilting leaves, large cankers and splitting bark followed by the death of the trunk and limbs. Roots were not affected, so they often sent up new shoots as high as 20 feet, but sadly, they too were destined to die.
The blight spread rapidly – as much as 50 miles per year killing nearly all chestnuts in its path. Quarantines and many chemical controls were tried, but all proved ineffective. Lumbermen became so frantic they started cutting down all remaining trees for the lumber before they too were infected. It was truly a catastrophe. Less than fifty years after the tree was at the peak of its commercial value, an estimated 3.5 billion trees had been lost to a fungus that had been accidentally brought to this country from Japan and China in horticultural products.
Scientists soon realized the only hope of saving the tree was to breed a disease-resistant variety. Early attempts at this were a short-lived federal government breeding project, and one begun in the 1970s by the Connecticut Agricultural Experiment Station where American chestnuts were crossed with disease-resistant Asian varieties. The Connecticut project continues today. This breeding program uses the “backcross” method in which the crossing and re-crossing is done over six or more generations in order to create fully resistant trees that are 15/16 American chestnut. This is quite a simplification of the process since many in-process checks are needed to assure resistant genes are passed on.
Because a generation is about six or seven years, and because of the need for testing of each generation to prove that the process has indeed been successful, seeds and disease-resistant 15/16 American chestnuts may not be widely available to the general public until about 2020.
More Bad News/Good News
Before you become too encouraged, let me tell you more of the story. It was reported in 2005 that the Oriental gall wasp, first introduced into the U.S. in 1974 by a grower who evaded foreign plant quarantine laws, lays its eggs in leaves and flower buds causing defoliated trees with no flowers. Fortunately, efforts to combat this wasp are now underway, and hopefully it will not become a major problem to restoration efforts.
As if that is not enough, a third foreign introduction, ink disease, looms as a major threat. Ink disease has been known for years as a danger, but only in recent years has there been serious work to produce a tree variety resistant to it. It is hoped this threat will also be overcome in a timely manner.
The Political Aspect
Dr. Douglas Jacobs of Purdue University reports that a major obstacle to reintroduction of the chestnut tree is the host of laws and regulations that now govern forests or former forests. In many public lands where the American chestnut once thrived, such as Great Smoky Mountains National Park, human interference is often discouraged or even illegal, calling for a unified approach that promotes exceptions to such laws.
What about Alabama, Georgia?
We should be interested because Northern Alabama and Georgia are within the original range of the American chestnut, and someday it may once again have an important place in our forests. My interest in seeing a living chestnut tree and in learning more about efforts to reestablish it was stimulated when I read that some large unaffected trees actually do exist. The largest chestnut in Alabama was found growing in Talladega National Forest in 2006 during a survey for a timber sale. It is 85 feet tall, and it, like a few others growing throughout the Southeast, has remained unaffected by the disease. I also learned that a stand of similarly unaffected trees was found near Pine Mountain, Georgia, also in 2006. Other states also have a few stands of mature chestnut trees that somehow have remained unaffected by the disease. An Alabama group is now attempting to breed resistant trees using the pollen from Alabama’s giant tree. Additionally, the American Chestnut Foundation, formed in 1983 and now boasting chapters in 18 states, has a huge ongoing backcross breeding program whose goals are to produce a disease-resistant variety and to make seeds and seedlings generally available to the public. While their work continues, and until those goals are accomplished, the Foundation encourages planting of pure American chestnuts and partially resistant crosses that are already available. This is because these can be viable, productive trees growing to 20 feet or more in height and producing a valuable crop of nuts before they too may be struck down by disease.
I learned all of this only because I decided to follow up on what was reported in an article in a barbershop magazine. So, I think the moral to this story must be – let’s be more aware of what is happening in our environment. Let’s develop an appreciation and concern for all of nature’s creations, and let’s do everything we can to support those who are dedicated to the preservation of any part of our environment facing the danger of being damaged or lost forever. I’ve learned a valuable lesson. How about you?
The American Chestnut Story, Sam Cox 1997
Chattooga Conservancy Quarterly, 2002
Sandra Angnostakis, Chestnut Breeding, 1996; Connecticut Chestnut Research, 2005
American Chestnut Foundation Journal, 2007
Restoring the Chestnut to Alabama, Morris, Neel and Boldin
Dr. Douglas Jacobs, Purdue University
(Photos courtesy of University of Georgia)