The imposing 100-foot American chestnut tree that once dominated forests in the eastern U.S. may soon return, fortified by a new resistance to an Asian fungus. That blight essentially wiped out the tree during the past century, altering entire forest ecosystems. Scientists are releasing a sixth-generation hybrid this year for planting in several locations, confident that it will show the resistance of its hardy Chinese cousin.

The hybridization began decades ago, when breeders crossed the American and Chinese chestnuts to obtain the resistance genes. But because the American variety grows up to 50 feet taller and lacks lower branches, the researchers have had to backcross repeatedly to recapture those traits. The sixth generation should now have about 94 percent American character and “should have high resistance to the blight,” says Sara Fitzsimmons, a research technologist at Pennsylvania State University’s School of Forest Resources who works on the project. She won’t rest assured, however, until the trees grow on national forest­land for 10 years or so. Meanwhile scientists will continue to breed seedlings optimized for the sharply different local conditions from Maine to Georgia.

If the sixth generation shows the required resistance, Fitzsimmons foresees chestnut trees being available in garden centers in about 25 years. And with oaks in decline because of gypsy moth infestation, the reemergence of hardy chestnuts would provide prodigious quantities of nuts for animals and valuable biodiversity.

Note: This article was originally printed with the title, "Chestnut Trees Return".

3 Comments

1. 1. candide 08:29 AM 4/30/09

   Next, the American Elm.

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2. 2. just_wondering 11:04 AM 4/30/09

   I pray this works and that the small percentage of non-native genetic material in the new chestnut hybrid doesn't produce unforeseen negative consequences.

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3. 3. PatriciaJH in reply to candide 08:21 PM 3/25/13

   Already, the American Elm! Dutch-Elm-Disease-resistant American Elms have been available for some time -- at least since 1995, according to Wikipedia. American Elms were not as hard-hit as the chestnuts; they still grow to breeding age and breed in the wild, and do quite well in river bottoms and wet areas, though they die relatively young. If something with ovoid, pointed, saw-toothed, sand-papery leaves shows up in your hedge, that's a young volunteer American elm.

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