Foggy morning followed by a sunny day.
The American chestnut was perhaps America’s greatest tree—until the chestnut blight was thoughtlessly imported from the Orient in 1904. It was giant tree with beautiful rot-resistant wood and a tasty and nutritious nut that fed a vast amount of wildlife and was an important food source for native Americans and European settlers. Some autumns chestnut mast would be over ankle deep in Appalachian forests.
Within 40 years of the blight’s arrival in New York over 4 billion chestnut trees were dead.
But a few survived hither and yon, including several in Wisconsin, and in 1983 the American Chestnut Foundation initiated a herculean effort to bring the tree back, employing selective breeding/backcrossing.
First an American chestnut is bred with a blight resistant Chinese chestnut, and the nuts are planted. This is the first filial or F1. At about 8 years of age these offspring are infected with blight fungus. Only those few trees showing exceptional resistance are kept. These are then bred (through controlled pollination) with an exceptional native American chestnut which shows some blight resistance on its own. The nuts are planted. This is back cross one, or BC1. The process in repeated until the third back cross is reached. Then two BC3 trees are bred. Finally, the best trees of this generation are bred once more. This makes for BC3F3 which is very much American but with good blight resistance.
BTW, the Chinese tree, apart from its blight resistance, is a wimpy little cousin the the American tree, so the goal is to borrow its good qualities, but get back as close as possible to the American original.
When neighbor Vi lost her huge silver maple last summer (at last giving our garden sufficient light) I suggested she might want to plant a chestnut. She agreed, and together we joined the ACF which entitled us to 4 BC3F3 seeds. The seeds arrived today. Vi has agreed to be tender of the seedlings. If all survive, each of our yards will be home to a marvelous tree, and, with our annual reporting responsibilities, we will be contributing in a small way to its restoration. And we might have two little trees looking for a good home.