Local names:
Chinese (qing gang li), English (ring cupped oak,blue japanese oak,bamboo-leaved oak), German (bambusblättrige eiche), Italian (quercia a foglie di bamboo), Nepali (sano phalant,sano pate phalant,banjh)
Q. glauca is a medium-sized (up to 20 m), attractive broadleaf evergreen tree, with an oval, rounded crown and a clear, cylindrical bole. Leaves alternate, simple, evergreen, oblong, elliptic, to obovate-oblong , 7-13 cm long, 2.5-6 cm wide, abruptly acuminate. Margin serrate on the upper half. Lamina glabrous and glossy green above, glaucous and silky hairy beneath. New foliage is either a rich green or bronze to purple-green. Very handsome when the new foliage emerges which usually occurs in early. Fruit a corn, 1 to 3 in a cluster, enclosed 1/3 in a downy cap with 6 to 7 raised concentric rings, ripens in one year. Acorns ovoid, 2 cm long, maturing (rarely in Europe) in one year.
Ecology
It occurs in secondary evergreen broad-leaved forest communities in north subtropical and warmer temperate zones of Asia, at elevations from 300-3100 m. It prefers moist, cool locations with good illumination, but can grow on a variety of soils. Slightly saline loams and neutral limestone soils promote the best growth, with pure stands occurring on deep, moist clays underlain with sandstone and shale. Q. glauca can withstand considerable shade up to the pole stage, but thereafter requires complete overhead illumination.
Native range
China, India, Japan, Nepal, Pakistan, Vietnam
Tree management
Q. glauca is propagated either by direct sowing or by planting nursery-raised seedlings. The seedlings are tolerant to shade, but older trees benefit from full light; seedlings are sensitive to frost and must be protected during the winter, but older trees are more frost-resistant. The tree prefers moist situations, such as north aspects and the sides of the ravines, and grows well on deep clay loams. It should not be planted on dry sites. The seedlings are liable to be browsed. Natural stands reach a height of 9.8-11.2 m and 9.8-12.5 cm d.b.h. after 25 years, with a standing volume of 80-92 cubic m per ha. . Managed plantations grow faster and can attain 8 m and 7.5 cm d.b.h. after 14 years. The tree coppices freely. Bare-root planting has given very poor results.
The seed ripens between October and December, according to the locality. The number of seeds per kg varies from 500-1900. In most localities the seedlings will need about 15 months in the nursery to reach a height of 15 cm.
It occurs in secondary evergreen broad-leaved forest communities in north subtropical and warmer temperate zones of Asia, at elevations from 300-3100 m. It prefers moist, cool locations with good illumination, but can grow on a variety of soils. Slightly saline loams and neutral limestone soils promote the best growth, with pure stands occurring on deep, moist clays underlain with sandstone and shale. Q. glauca can withstand considerable shade up to the pole stage, but thereafter requires complete overhead illumination.
The recalcitrant seeds quickly lose viability if allowed to dry out. It can be stored moist and cool over winter but is best sown as soon as it is ripe in an outdoor seed bed, though it must be protected from mice, squirrels etc. Small quantities of seed can be sown in deep pots in a cold frame. Plants produce a deep taproot and need to be planted out into their permanent positions as soon as possible, in fact seed sown in situ will produce the best trees. Trees should not be left in a nursery bed for more than 2 growing seasons without being moved or they will transplant very badly.
Seeds, raw or cooked have a sweet taste. The seed can be dried, ground into a powder and used as a thickening in stews etc or mixed with cereals for making bread. If the seed contains bitter tannins, these can be leached out by thoroughly washing the seed in running water though many minerals will also be lost. Either the whole seed can be used or the seed can be dried and ground it into a powder. It can take several days or even weeks to properly leach whole seeds, one method was to wrap them in a cloth bag and place them in a stream. Leaching the powder is quicker. A simple taste test can tell when the tannin has been leached. The traditional method of preparing the seed was to bury it in boggy ground overwinter. The germinating seed was dug up in the spring when it would have lost most of its astringency. The leaves are cooked as a famine food. The roasted seed is a coffee substitute.
Timber: The wood is a good quality timber with a fine texture and straight grain. The specific gravity is about 0.89 g/cubic cm. The wood is hard, fairly durable and used for heavy and light construction purposes, railway sleepers, posts, stakes, poles, making containers and furniture and as fuelwood.
Tannin or Dyestuffs: Oak galls are excrescences that are sometimes produced in great numbers on the tree and are caused by the activity of the larvae of different insects. The insects live inside these galls, obtaining their nutrient therein. When the insect pupates and leaves, the gall can be used as a rich source of tannin, that can also be used as a dyestuff.
Medicine: It has been used in traditional medicine as an astringent treatment for haemorrhoids.
Ornamental: This tree often used as a residential shade tree
Other services: This tree is recommended for buffer strips around parking lots or for median strip plantings in the highway. The branches and twigs are good material for culturing mushrooms (for example, Pleurotus eryngii).