The American chestnut was once one of the most important trees in our eastern hardwood forests. It ranged from Maine to Georgia, and west to the prairies of Indiana and Illinois. It grew mixed with other species, often making up 25 percent of the hardwood forest. In the virgin forests of the Appalachian Mountains, the ridges were often pure chestnut and mature trees could be 600 years old and average 4 to 5 feet in diameter and 80 to 100 feet tall.
The Story of the American Chestnut
Then blight struck. First discovered in 1904 in New York City, the lethal fungus – an Asian organism to which our native chestnuts had very little resistance – spread quickly. By 1950, except for the shrub-like sprouts the species continually produces (and which also usually become infected), the American chestnut had virtually disappeared from eastern forests.
The Story of Chestnut Blight
The blight (initially named Endothia parasitica and later changed to Cryphonectria parasitica) was first reported in 1904. Huge efforts were taken by state and federal governments to halt it spread, with Pennsylvania even cutting a several miles wide swath of forest to halt its spread westward. As it became clear that efforts to contain the spread were not working, efforts shifted to creating a blight resistant variant of the tree.In 1925 the US Deptartment of Agriculture began a program aimed at developing blight-resistant hybrids that would be able to compete in the forests.
Early Breeding Efforts
A group of prominent plant scientists, including Nobel Prize-winning plant breeder Dr. Norman Borlaug; Dr. Peter Raven, Director of the Missouri Botanical Garden; independent chestnut researcher Philip Rutter; and the late Dr. Charles Burnham, the eminent Minnesota corn geneticist, developed the backcross breeding program for which TACF was developed to implement.
Modern Tree Breeding
In 1989 The American Chestnut Foundation (TACF) established the Wagner Research Farm in Meadowview, VA, to start the backcrossing program developed by TACF founding scientists Charles Burnham, David French, and Philip Rutter. Plant pathologist Fred Hebard was persuaded to move to Meadowview to manage the research farm, where he immediately began testing the backcross method. By 1993, Hebard had produced thousands of healthy trees, including several highly blight-resistant seedlings, from two intercrossed generations.
TACF Grows Trees