Library Index » Science Encyclopedia » Plants - The American Chestnut Tree—making A Comeback?, Protection Of Plants Under The Endangered Species Act, Threatened And Endangered U.s. Plant Species

Plants - The American Chestnut Tree—making A Comeback?

trees blight species disease

During the 1800s the American chestnut (Castanea dentate) was the predominant tree of many forests in the eastern United States. Its range extended from Maine to Mississippi, as shown in Figure 11.1. The heaviest concentrations were in the southern Appalachian Mountains where the tree made up more than a third of the overstory trees (the topmost layer of foliage in a forest). Mature trees reached three to five feet in diameter and rose to ninety feet in height with a huge canopy. The species was fast-growing and produced light, durable wood that was extremely popular for firewood and for making furniture, shingles, caskets, telephone poles, railroad ties, and other products. The trees were also valued for their chestnuts and tannin content. Tannin is an extract used in the leather industry.

In 1904 observers in New York City reported that an unknown blight (disease) was killing American chestnut trees at the Bronx Zoo. By 1940 the blight had spread through the entire range of the species, leaving all of the trees dead or dying. The tree structure was not damaged by the disease, so harvesting continued of dead trees for several more decades. Although sprouts would grow from the stumps left behind, they eventually succumbed to the blight. By the 1970s the American chestnut had been virtually eliminated. More than three billion trees had been killed. The culprit was a fungus originally called Endothia parasitica, but later renamed Cryphonectria parasitica. Scientists believe the disease came into the United States with ornamental chestnut trees imported from Japan or China. The Asian trees could carry the disease, but not succumb to it, because of natural immunity.

During the 1920s frantic efforts began to cross the remaining American chestnut trees with the Asiatic species. Although hybrid trees resulted with some resistance to the blight, they were inferior in quality to the original FIGURE 11.1 Historical distribution of the American chestnut "Figure 1. Natural Range of American Chestnut," in American Chestnut—An Anerican Wood, U.S. Department of Agriculture, U.S. Forest Service, February 1973, http://www.fpl.fs.fed.us/documnts/usda/amwood/230chest.pdf#search='American%20chestnut' (accessed March 10j, 2006)American species. Advances in genetic research and forestry techniques led to better hybrids by the 1980s. As of 2006 research continues by two foundations—the American Chestnut Foundation (a nonprofit organization headquartered in Vermont) and the American Chestnut Cooperators' Foundation (ACCF) at Virginia Tech University. The American Chestnut Foundation focuses on crossing naturally blight-resistant Asiatic species with American species. The ACCF produces crosses between American chestnut trees found to have some resistance to the blight in hopes of eventually producing offspring with higher resistance. Both organizations are confident that vigorous blight-resistant American chestnut trees can be developed during the twenty-first century.

Plants - Protection Of Plants Under The Endangered Species Act [next]

User Comments

Your email address will be altered so spam harvesting bots can't read it easily.
Hide my email completely instead?

Cancel or

Vote down Vote up

over 8 years ago

I know where there are 4 american chestnut trees, without blight, in Pennsylvania. We need to save them, as a sewage project is trying to cut them down, or disturb the root system. Please call 724 337 3832 if you can help save them. By the way, lots of seeds every yeear. Sweet, almost like butter when they are roased over a fire. My dog fights with me over them. Please help me (George Spisak) save them from distruction.