A hybrid, 25 years in the making, is designed to resist a devastating blight.
Tromping through a Massachusetts state forest, Brad Smith spots an old stump with dead shoots and one lone, green sprout – a sad but not uncommon remnant of a once-proud species – the American chestnut tree.
Except for a few mature trees, the species has struggled for 50 years to survive. It does that in the same way: Stumps send up sprouts that are quickly attacked by the same invasive blight that wiped out about 3.5 billion chestnut trees between 1904 and 1950.
"What you're seeing is the former king of the forest reduced to surviving as a mere shrub," says Mr. Smith, president of the Massachusetts chapter of the American Chestnut Foundation (ACF).
Now, however, an American chestnut revival may be imminent. Scientists using traditional plant breeding techniques are on the verge of a breakthrough. In fact, Smith smiles and shares a little secret: the "holy grail" of American chestnut trees – a hybrid supertree fully resistant to the blight – is alive and growing down south.
Hidden on a country road that winds through rural Meadowview, Va., is a 93-acre plot of ground that holds the future of the American chestnut: about 120 hybrid saplings. The trees – going on two years old and four feet tall – are considered "fully blight resistant" and are thriving.
At this rate, by 2010 there should be enough "holy grail" nuts to begin planting in selected test sites in national forests. By 2015, production from such plots is expected to grow exponentially – yielding enough nuts to allow for full-blown replanting – if everything goes well.
Cross-breeding American chestnut trees is a challenge because they do not produce fruit until their sixth year. Researchers have spent 25 years breeding resistant Chinese varieties of chestnut with nonresistant American versions – then "back-crossing" or breeding resistant American chestnuts with one another. It's a difficult project that the US government attempted but dropped long ago.