About Castanea mollissima Blume
Castanea mollissima Blume, commonly known as the Chinese chestnut, is a deciduous tree that grows up to 20 metres (66 ft) tall, with a broad crown. Its leaves are alternate and simple, 10–22 centimetres (4–8+1⁄2 in) long and 4.5–8 cm (1+3⁄4–3+1⁄4 in) wide, with toothed margins. It produces flowers in catkins that are 4–20 cm (1+1⁄2–7+3⁄4 in) long: female flowers grow at the base of each catkin, while male flowers grow along the rest of the catkin. Its fruit is a densely spiny cupule 4–8 cm (1+1⁄2–3+1⁄4 in) in diameter, which contains two or three glossy brown nuts. On wild trees, these nuts measure 2–3 cm (3⁄4–1+1⁄4 in) in diameter. The species epithet mollissima refers to the softly downy texture of its new shoots and young leaves. This species is native to China, Taiwan, and Korea. It has been cultivated in East Asia for millennia, so its exact original natural range cannot be confirmed. It has been recorded in the Chinese provinces of Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Nei Mongol, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Xizang, Yunnan, and Zhejiang, as well as in Taiwan and Korea. In the northern part of its range, it grows near sea level, while in the southern part of its range it can grow at altitudes up to 2,800 m. Chinese chestnut prefers full sun and acidic, loamy soil, and it has a medium growth rate. When grown near other chestnut species including Japanese chestnut, American chestnut and European sweet chestnut, Chinese chestnut readily cross-pollinates with these species to form hybrids. Chinese chestnut has evolved over a long period while coexisting with Cryphonectria parasitica (formerly Endothia parasitica), the fungus that causes chestnut blight. It has evolved strong blight resistance, likely more than any other chestnut species. While it is not fully immune to the disease, it usually only sustains minor damage when infected. Blight resistance varies considerably between individual Chinese chestnut trees: some individual trees are quite susceptible to blight, while others are essentially immune. Japanese chestnut is also comparatively resistant to chestnut blight, while European chestnut is somewhat less resistant. In the 1890s, Chinese and Japanese chestnuts were imported to the United States, to be grown as orchard trees because of their small, compact size compared to the large American chestnut. This introduction had disastrous results, as the imported Asian chestnuts carried chestnut blight, to which the American chestnut (Castanea dentata) had no natural resistance. The disease was first observed on a tree at the Bronx Zoo in 1904, and spread rapidly out of control, devastating American chestnut populations. Within 30 years, almost no mature American chestnuts remained in their native range. An active cross-breeding program has been carried out in North America, crossing Chinese chestnut with American chestnut. The goal of this program is to combine desirable traits from American chestnut such as larger stature and sweeter nuts, while retaining the blight resistance from Chinese chestnut. The nuts of Chinese chestnut are a significant food source for wildlife. The nuts are edible, and the tree is widely cultivated across eastern Asia. Over 300 cultivars have been selected specifically for nut production, and are grouped into five major regional cultivar groups: Northern, Yangtze River Valley, Sichuan and Guizhou, Southern, and Southwestern. The Dandong chestnut, which belongs to the Japanese chestnut (Castanea crenata), is a major cultivar grown in Liaoning Province. Some Chinese chestnut cultivars, including 'Kuling', 'Meiling', and 'Nanking', produce large nuts up to 4 cm in diameter. The nuts of Chinese chestnut are sweet; some people consider them to have the best flavor of any chestnut, while others think they do not taste as good as American chestnut.
