Castanea dentata can be distinguished by a few morphological traits, such as leaf shape, petiole length and nut size. There are several other chestnut species, such as the European sweet chestnut ( C. It is considerably larger than the closely–related Allegheny Chinquipin Castanea pumila. Ĭastanea dentata is a rapidly–growing deciduous hardwood tree, historically reaching up to 30 metres (98 ft) in height, and 3 metres (9.8 ft) in circumference. Alternate approaches to developing a blight-resistant cultivar include cross-breeding among partially blight-resistant American chestnuts or crossbreeding with the moderately blight-resistant Chinese chestnut, then backcrossing with the American Chestnut, with the goal of retaining most of its genes. If approved, these chestnut trees would be the first genetically modified forest trees released into the wild in the United States. As of 2021, the researchers who developed this cultivar are working towards applying for government permission to make these trees available to the public. When expressed in the vascular cambium of the Darling 58 cultivar, the oxalate oxidase enzyme degrades the oxalic acid produced by the chestnut blight, reducing damage to the vascular cambium and resisting girdling of the trunk. Scientists at the SUNY College of Environmental Science and Forestry created the Darling 58 cultivar of American chestnut by inserting the oxalate oxidase gene from wheat into the genome of an American chestnut. Several groups are attempting to create blight-resistant American chestnuts. American chestnuts are also susceptible to ink disease, particularly in the southern part of its native range this likely contributed to the devastation of the species. The species is listed as endangered in the United States and Canada. There are hundreds of large (2 to 5 ft diameter) American chestnuts outside its historical range, some in areas where less virulent strains of the pathogen are more common, such as the 600 to 800 large trees in Northern Michigan. Very few mature specimens of the tree exist within its historical range, although many small shoots of the former live trees remain. It is estimated that between 3 and 4 billion American chestnut trees were destroyed in the first half of the 20th century by chestnut blight after the blight's initial discovery in North America in 1904.
The species was devastated by chestnut blight, a fungal disease that came from Chinese chestnut trees introduced into North America from East Asia. The American chestnut was one of the most important forest trees throughout its range and was considered the finest chestnut tree in the world. As is true of all seven species in genus Castanea, the American chestnut produces burred fruit with edible nuts. The American chestnut ( Castanea dentata) is a large, fast-growing deciduous tree of the beech family native to eastern North America.
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