Geography and distribution
Gmelina arborea is native to Pakistan, Bhutan, India, Myanmar, Thailand, Indo-China and South China. It is found in tropical forest to 1,100 metres above sea level. Gamhar has also been introduced to most tropical countries as a timber tree.
Gamhar is a tree that can grow to 30 m high, with smooth, whitish to greyish reddish-brown bark and a straight trunk. Its leaves are 8 to 20 cm long, 4.5 to 15 cm wide, and covered with star-shaped hairs. Two large glands are paired at the base of each leaf. The outer surface of the calyx (sepals) is scattered with flat, round glands. The flowers are reddish-yellow, hairy and five-lobed. The hairless fruits are 10 to 15 mm in diameter and glossy yellow when mature. They are recorded as having a bittersweet taste.
Threats and conservation
Gmelina arborea is not considered to be threatened, and can be found growing in the wild in many countries, as well as in large numbers in plantations.
Gamhar produces high-quality wood, which is harvested for the manufacture of furniture and musical instruments. It is also used as structural timber, for instance in mines and ship building, as well as joinery, and to make plywood, matches, agricultural implements and even artificial limbs. The wood also produces good quality pulp used in the manufacture of cardboard and various grades of paper.
Flowers of Gmelina arborea
Gmelina arborea has a wide range of local medicinal uses. The juice of young leaves has been used to treat gonorrhoea and as a cough medicine. The leaf juice has also been used externally to treat ulcers. A paste of the leaves has been applied to treat headaches associated with fever. The root has been used to treat epilepsy, fever and indigestion. The bittersweet fruit has been included in cooling decoctions given for fevers.
Gmelina arborea is a useful multipurpose shade tree for coffee and cocoa plantations; it suppresses grasses and provides livestock fodder. The leaves are also used for silkworm culture. Gamhar is also cultivated as a garden ornamental and as a street tree. In Malawi it has been grown in plantations, to be harvested as fuelwood, mostly for use in tobacco barns. Nectar from the flowers yields high-quality honey.
Gmelina arborea has been used in revegetation programs, as it grows quickly and provides shade for forest species to germinate under. When the forest species are established, the wood of Gmelina arborea can then be harvested.
Millennium Seed Bank: Seed storage
Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.
Description of seeds: The fruit is a one- to four-seeded drupe. Seeds are dispersed by animals. Average 1000 seed weight = 923 g.
Number of seed collections stored in the Millennium Seed Bank: One.
Seed storage behaviour: Orthodox (the seeds of this plant survive being dried without significantly reducing their viability, and are therefore amenable to long-term frozen storage such as at the MSB).
Close up of gamhar in Sabah
Gamhar thrives in full sunlight, although it can tolerate some shade. It is moderately frost-hardy, and can recover quickly from frost injuries. It grows best in fertile, well-drained soils, and is normally propagated by seed. For rapid germination, fresh seed should be soaked in cold water for 48 hours. The seed should then be sown in a mixture of sand and loam at 22 - 25˚C, and will germinate within two to three weeks. An alternative method of propagation involves taking cuttings from the tips of two- to three-week-old plants. The cuttings should be 12 cm long and include the terminal bud and four to six leaves, each reduced to one third of its surface area. Cuttings should be misted and kept at 22 - 25˚C. It is also possible to propagate this species by layering or grafting.
Gamhar at Kew
There are 33 specimens of Gmelina arborea in the Economic Botany Collection and these include samples of wood, fruits, roots and artefacts such as a wooden bowl.
The Herbarium (one of the behind-the-scenes areas of Kew) contains many dried specimens of Gmelina arborea.