Infections of the American Chestnut Tree Essay

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Cryphonectria parasitica, a filamentous, ascomycete fungus, is the causal agent of the chestnut blight5,14 which was introduced to North America from Japan circa 190412,14.The chestnut blight infects all members of the Castanea family14, and some members of the genus Quercus though C. parasitica infections are superficial14. A C. parasitica infection typically begins at a branch node or wound in the tree’s bark 14. Once a spore has entered the tree, hyphal growth begins14. When the fungi’s hyphae reach the cambium, the xylem and phloem are blocked, cutting off the transport of water and nutrients and a sunken canker is formed14. Eventually, the lack of water and nutrients kills the tree above the point of infection14. As a fungus, C.…show more content…
One excellent use for blight-resistant American chestnuts is reclaiming surface mines. Though other species of trees can survive in the harsh conditions typical of surface mines, they have little to no value as lumber and provide little for wildlife4. Chestnuts would also provide a fast growing lumber source, one that is lightweight, strong, and moderately rot-resistant. Additionally, the large nut crops produced by the American chestnut would increase the ecosystems carrying capacity for wildlife, and moderate population fluctuations that follow mast (nut crop) fluctuations. For these and other reasons which space here does not permit, restoring the American chestnut is worthwhile endeavor. Although C. dentata is not resistant to an infection by the blight fungus, it is not entirely defenseless. One attempt at warding off C. parasitica is the growth of callus encircling the fungi’s mycelium to prevent its spread (cite). This may or may not work, in either case the fungi will spread to another site on the tree via sporulation. A second barrier to blight infection is the chestnut’s relatively high levels of tannic acid(s) in the cambium (cite). However, as will be discussed later, tannic acids may benefit the blight. The most promising method for increasing C. denata’s blight resistance is The American Chestnut Foundation’s breeding program. To give the chestnut the advantage in its battle with its evolutionary foe, it is necessary to study the factors that make C.
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