Oriental Castanea species have sufficient resistance to survive the disease. For instance, over 6000 mature trees have been found in northern Michigan (Buisch 1978). A few mature trees remain, especially beyond the northwestern extent of the American chestnut’s range, where the infectious fungus spores are not so prevalent. As a result, chestnut saplings are a common sight in native forests. This pestilence, which was probably introduced from the Orient on nursery stock around 1890, is one of the most devastating epidemics of a plant disease caused by a pathogen from a foreign country.īecause the blight fungus does not live below the ground level, stumps of diseased trees continue sending up healthy sprouts that eventually become infected and die, but in succession these sprouts keep the tree’s root system alive for many years. Eventually, it completely decimated the American chestnut as a commercial forest tree. ![]() ![]() The chestnut blight, as the disease was called, spread outward from New York City at the rate of 20 miles per year. Large trees often died within two years of the first infection. Investigations revealed a fungal, bark-canker disease that impeded the flow of sap. In that year chestnut trees in New York City were found dying of an unknown cause. It was valued highly for its versatile decay-resistant wood, and its nut crops provided food for humans and substantial forage for livestock and wildlife. In this country the American chestnut was the most important deciduous forest tree at the turn of the century. Both are relatively starchy, and their sugars are less soluble than those of the other chestnut species. The nuts of the European chestnut are similar to those of the Japanese chestnut. More than 4500 metric tons are currently exported to the United States yearly. Even so, over 180,000 metric tons of European chestnuts are produced annually in France and Italy alone. Production has been reduced 85 percent since the turn of the century, both because of a decline of agrarianism in the region and he combined effect of a root-rot disease and the chestnut blight. In addition to yielding great quantities of nuts (27,000 metric tons annually), the Japanese chestnut produces strong, durable wood that is used in fine woodwork, ships, and railroad ties.įor centuries the European chestnut has been a staple food and export commodity in the rural, hilly areas of southern Europe. The planting of chestnuts in both Japan and Korea has increased in recent decades, yet total production has remained about the same because of increasing damage from a devastating new pest called the gall wasp. The Japanese chestnut, which is also native to southern Korea, has been cultivated in Japan for at least 3000 years and perhaps as many as 7000. Of the north temperate species, it is the most resistant to blight. Centuries of seed selection have improved its resistance to chestnut blight and its production of nuts, but its wood remains very lightweight and weak and therefore has no commercial value. The Chinese chestnut is cultivated in its native China and Korea. ![]() ![]() mollissima Blume, the Chinese chestnut C. The chestnut blight fungus ( Endothia parasitica) comes from Asia, and Castanea species of that region have evolved various degrees of resistance, whereas European and American species are highly susceptible.įour species of Castanea have been commercially successful: C. The genus originally evolved in the Orient, spreading west to Europe and east to North America via the Alaskan land bridge. The chestnut genus, which has 12 (Camus 1929) or 13 (Jaynes 1975) species, is in the same family (Fagaceae) as oaks and beeches. Though commercial plantings are still a questionable enterprise in many areas, home production of chestnuts can be highly recommended for suitable sites (zones 5 and 6) in the northeastern United States. These efforts, combined with the great genetic variability within the chestnut genus, seem destined to reassert the chestnut’s preeminence as a forest and orchard tree. In response to these setbacks, chestnut research has increased worldwide (Jaynes 1975). During the 20th century, however, the chestnut’s contribution has been reduced drastically by disease and pestilence. Will the chestnut’s future equal its past? Since before recorded history, species in the chestnut genus Castanea have been prime sources of food and wood in vast areas of Asia, Europe, and North America.
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