The American Chestnut was once the most populous tree species in the eastern United States, numbering in the excess of four billion individual trees. Many of these were true giants, up to 150 feet tall, with trunks more than 12 feet thick. The trees’ nutritious nuts were a primary pre-winter food for many birds and mammals, including turkeys, bears, deer, pigs and squirrels.
Tragically, in the first half of the twentieth century this magnificent tree was almost completely wiped out by Chestnut Blight (Cryphonectria parasitica). Accidently brought from Asia to New York in the 1890s, the disease needed only a few decades to spread through the tree's entire native range. Only a few rare trees in that range still survive, along with some old stumps that sometimes send up shoots from their roots. Nearly all of the known healthy trees are isolated specimens that had been planted in western states and other areas unaffected by the blight.
But there is a good chance that the American Chestnut can be rescued and even re-established in its old range. By working with genetic material from surviving trees, scientists hope to develop disease-resistant strains. In one approach, the offspring of hybrids with a resistant Asian species are repeatedly crossed with the pure American species, and the Asian tree's characteristics are gradually bred out over a number of generations. It is thought that this process can eventually lead to a 98% pure American form.
There is also interest in the possibility of developing resistant strains from the few trees that still survive in the blight-affected area, but at this point no one knows if that is feasible. Another possible solution to the problem is to insert a disease-resistance gene directly into the American tree's DNA. This could potentially produce an almost 100% pure American form.
It is important to preserve as much of the species' natural diversity as possible, and for this reason scientists want to eventually develop numerous resistant strains. To pave the way for future work in this direction, efforts are being made to collect and preserve genetic material from a large number of surviving trees.
Cultivation Zones – warmer parts of Zone 4 south into Zone 8. Native Range – the original range ran in a broad irregular swath from upper New England south to Alabama and Mississippi.
Myths and stories:
In the American folk tradition, carrying a chestnut in one’s pocket could bring good luck. Lucky chestnuts were carried in men’s pockets, sometimes through the decades of a man’s life.
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