"American Chestnut Makes a Slow Comeback" appeared in the Spring 2009 issue of Forest Notes. The following is some additional information. Visit the Vermont/New Hampshire chapter of The American Chestnut Foundation to learn more.

This chestnut tree in Merrimack, NH has already been infected with chestnut blight. The blight fungus causes girdling cankers that block the flow of water and nutrients, eventually killing the tree.

These chestnut burs have been manually cross-pollinated to retain as much of the American chestnut germplasm as possible while maintaining the level of blight resistance provided by the Chinese chestnut.

Chart: Intercrossing generations allows for increased levels of blight resistance. Click here for a larger image.

Chart: The American Chestnut Foundation starts with a cross between American and Chinese chestnut trees, followed by three or four generations of backcrossing to different American chestnuts, followed by two generations of intercrossing resistant offspring.Click here for a larger image (759 KB PDF).