Recovering the American Chestnut Tree

Once it was the dominant over story tree of the eastern American forest.  The species is fast growing and large, reaching heights of 80ft and three to four feet in diameter. [photo]  Its tree is prized for it wood that has straight grain and hardness.  Chestnuts were roasted over an open fire (at least according to Nat King Cole) and fed the hogs, which were released into the forest to feast on the burrs.  Wildlife likes chestnuts too.  The species was all but eliminated by a blight introduced through Japanese specimens beginning in New York in 1904, considered one of the largest ecological disasters in modern times.  A staggering four billion trees were killed in just forty years. A few wild chestnut trees have managed to survive, and stumps continue to produce shoots that succumb within a few years. So the pure genetic code is still available to us.

Efforts are underway to restore the chestnut tree to its place in American deciduous forests.  The American Chestnut Foundation is conducting research to develop blight resistant strains.  Asian chestnut trees are resistant to blight, so a back-cross breeding program is underway to find a suitable variety to reintroduce.  Breeders want to retain as much American genome as possible while obtaining blight resistance from Asian genes.  Asian trees look different and grow differently in the forest.

The blight fungus lives in the tree's cambium where it spreads and girds the tree killing it.  A resistant tree forms a canker which stops the fungus from spreading.  The University of Virginia has been conducting breeding research for fifty years and is working with the Foundation to establish a breeding colony from which seedlings can be planted in Virginia's forests.  This type of breeding program is important for other species such as ash and white pine, both of which are suffering from disease.