Quercus dentata, the Japanese Emperor Oak, also Daimyo oak (Japanese: カシワ or 柏, kashiwa; simplified Chinese: 柞栎; traditional Chinese: 柞櫟; pinyin: zuòlì; Korean: 떡갈나무, tteokgalnamu) is a species of oak native to Japan, Korea and China. The name of the tree is often translated as "sweet oak" in English to distinguish it from Western varieties.
It is a deciduous tree growing up to 20-25 m tall, with a trunk up to 1 m diameter. Its foliage is remarkable for its size, among the largest of all oaks, consisting of a short hairy petiole, 1–1.5 cm long, and a blade 10–40 cm long and 15–30 cm broad, with a shallowly lobed margin; the form is reminiscent of an enormous pedunculate oak leaf. The leaves are often retained dead on the tree into winter. Both sides of the leaf are initially downy with the upper surface becoming smooth.
The flowers are produced in May; the male flowers are pendulous catkins. The female flowers are sessile, growing near the tips of new shoots, producing acorns 1.2–2.3 cm long and 1.2–1.5 cm broad, in broad, bushy-scaled cups; the acorns mature in September to October.
Cultivation and uses
It was introduced to the British Isles in 1830, where it is occasionally grown in botanical gardens. It is usually smaller in cultivation than in the wild, growing to a small angular tree or large irregular shrub. Notable specimens include one at Osterley Park 14 m tall and 1.5 m girth, and the largest, 18 m tall, at Avondale Forest Park, County Wicklow, Ireland.
- World Conservation Monitoring Centre (1998). Quercus dentata. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 12 May 2006.
- Flora of China: Quercus dentata
- Quercus dentata, with photos (pdf file; in Japanese)
- Phillips, R. (1978). Trees in Britain, Europe and North America. Ward Lock.
- Mitchell, A. F. (1974). Field Guide to Trees in Britain and Europe. Collins.
- Lancaster, R. (1981). Hillier's Manual of Trees & Shrubs, 5th ed. Hillier and Sons.
- (French)Chênes: Quercus dentata