The American chestnut tree was once a majestic species – one of the tallest and quickest-growing trees in the country. But what was once a valuable food and wood source for the United States was all but wiped out by a devastating disease. In this article, we’ll discuss what killed the American chestnut tree, and what scientists are doing to try and save it.
What You'll Learn Today
What Has Caused the Widespread Decline of the American Chestnut Tree?
The American chestnut tree thrived for at least 40 million years. Thanks to its rapid growth and ability to reach extreme heights, it was prolific in U.S. forests, particularly in the eastern half of the country.
In addition to its fast, tall growth, the wood of the chestnut tree was rot-resistant and perfect for making furniture and building structures. Its nutritious, edible nuts were a food source for wildlife and humans alike.
Needless to say, the American chestnut tree was a valuable resource in countless ways. In the early 1800s, however, things started to go downhill for the species.
Phytophthora cinnamomi, or Ink’s disease, delivered a major blow to the chestnut population. This soil-borne pathogen slowly destroys the root system of the tree, eventually causing its death.
The point of no return for the American chestnut came in the early 1900s with the introduction of another fungus called Cryphonectria parasitica. Commonly known as chestnut blight, the disease is native to East and Southeast Asia, and was introduced around the turn of the century in the US and Europe.
Once the blight started to spread, the damage caused a significant amount of trees to die. The American chestnut still exists today, but only as a mere shrub that lives for about 5 years.
The tree is not technically extinct since the blight fungus does not kill the tree’s root system underground. But although the tree sends up sprouts that grow well, it ends up dying back to the ground soon afterward.
Therefore, scientists consider the American chestnut tree to be “functionally extinct”.
How Many American Chestnut Trees Are Left?
Of the billions of American chestnut trees that proliferated our forests a century ago, only a few dozen pre-blight mature trees soldier on today. There are hundreds of millions of sprouts that continue to shoot up from intact root systems, but these trees are all doomed to die from the blight fungus.
Can the American Chestnut be Saved?
The American Chestnut Foundation (TACF) is an organization that has become instrumental to the tree’s future by working to reintroduce it into our forests. Since the 1970s, this group has been implementing a restoration program with a breeding strategy that will gradually improve the tree’s disease tolerance.
TACF’s approach to saving this tree species is called 3BUR. Here’s how it works:
TACF has a research farm located in Virginia where volunteers have planted over 500 orchards. In the past 30+ years, American chestnuts have been bred with blight-resistant hybrids of the species.
Today, thanks to this breeding program, a genetically diverse population of American chestnut hybrids exists. TACF credits Chinese chestnuts with improving the blight tolerance of the American offspring.
This solid progress will continue to improve the chestnut’s blight tolerance, and they will start working on integrating resistance to Pytophthora cinnamomi (ink spot disease) as well.
At the State University of New York, College of Environmental Science and Forestry (SUNY ESF), scientists recently discovered a gene present in wheat contains an enzyme that improves blight tolerance. This discovery allows TACF to incorporate the gene into their breeding program, and increase the amount of American chestnut genes in their orchards.
Researchers with the TACF are also working on attacking the blight fungus directly. Using a technique called hypovirulence, scientists infect the fungus with a virus, which makes the fungus ill and diminishes its ability to cause chestnut infections.
With this method, the American chestnut tree has a better chance at being able to pause the production of its cankers and survive the weakened blight infection.
Can I Plant an American Chestnut?
The American Chestnut Foundation shares its best research seeds with its seed-level members. There is a fee to become a member and obtain seeds. The foundation does not currently sell the seeds to the general public.
Although TACF only allows members to receive blight-resistant seeds, the organization still encourages people to plant pure American chestnuts. Even though they only live for a few years, it’s still beneficial to the species.
Planting the blight-susceptible American chestnuts help to preserve the native sources of trees as well as the genetic diversity of the species. Also, it helps Americans practice growing and maintaining chestnut trees in a variety of land sites, which could help in the future when more trees are introduced.
To plant an American chestnut tree, you will need:
- Well-draining, mildly acidic soil with a pH of 4.5-6.0
- Full sun for the trees to flower
- At least two trees for cross-pollination
To plant the chestnuts, you can either seed them directly into the ground in the spring, or start them in a pot indoors and transplant them later. The American Chestnut Foundation encourages planters to use this guide to grow your trees successfully.
The decimation of the American chestnut tree was a huge blow to our environment. It’s important to continue to work on reintroducing this valuable source of resources to U.S. forests.
The American Chestnut Foundation’s YouTube channel has a wealth of videos to keep viewers posted on their progress.
This recent video is part of their “Chestnut Chat” series, and discusses the properties of chestnut wood: