Gmelina arborea,, locally known as gamhar, is a fast-growing deciduous tree in the family Lamiaceae.
Description
Gmelina arborea is a fast-growing tree, which grows on different localities and prefers moist fertile valleys with 750–4500 mm rainfall. It does not thrive on ill-drained soils and remains stunted on dry, sandy or poor soils; drought also reduces it to a shrubby form. The tree attains moderate to large heights of up to 30 m, with a girth of 1.2 to 4 m. It has a chlorophyll layer just under the outer bark, which is pale yellow on the outside and white inside. Gmelina arborea wood is pale yellow to cream-coloured or pinkish-buff when fresh, turning yellowish brown on exposure and is soft to moderately hard, light to moderately heavy, lustrous when fresh, usually straight to irregular or rarely wavy grained and medium course textured. Flowering takes place during February to April when the tree is more or less leafless whereas fruiting starts from May onwards up to June. The fruit is up to 2.5 cm long, smooth, dark green, turning yellow when ripe and has a fruity smell. This tree is commonly planted as a garden and an avenue tree; growing in villages along agricultural land and on village community lands and wastelands. It is light demander, tolerant of excessive drought, but moderately frost hardy. It has good capacity to recover from frost injury. Gamhar trees coppices very well with vigorous growth. Saplings and young plants need protection from deer and cattle.
Distribution and habitat
Gmelina arborea grows naturally throughout India, Myanmar, Thailand, Laos, Cambodia, Vietnam and in southern provinces of China. It is found at altitudes from sea level to. Since the 1960s, it has been introduced extensively as fast-growing timber trees in Brazil, Gambia, Honduras, Ivory Coast, Malaysia, Malawi, Nigeria, the Philippines, and Sierra Leone. It is also planted in gardens and avenues.
Utilization of the species
Gmelina arborea timber is reasonably strong for its weight. It is used in construction, furniture, carriages, sports, musical instruments and artificial limbs. Once seasoned, it is a very steady timber and moderately resistant to decay and ranges from very resistant to moderately resistant to termites. Its timber is highly esteemed for door and window panels, joinery and furniture especially for drawers, wardrobes, cupboards, kitchen and camp furniture, and musical instruments because of its light weight, stability and durability. It is also used for bentwood articles. In boat building it is used for decking and for oars. Gmelina arborea is a popular timber for picture and slate frames, turnery articles and various types of brush backs, brush handles and toys also for handles of chisels, files, saws, screw drivers, sickles etc. The wood is also used for manufacturing tea chests and general purpose plywood, blackboards, frame core and cross bands of flush door shutters. In the instrument industry gambhar timber is widely employed for the manufacture of drawing boards, plane tables, instrument boxes, thermometer scales and cheaper grade metric scales. It is also used in artificial limbs, carriages and bobbins. It is an approved timber for handles of tennis rackets, frames and reinforcements of carom boards and packing cases and crates. Gamhar is used in papermaking and in the matchwood industry too. The Lion Throne, the most important, and last surviving, of the eight royal thrones of Myanmar, now in the National Museum in Yangon, is carved from Gmelina arborea wood. Gmelina arborea leaves are considered good for cattle and are also used as a feed to eri-silkworm. 'Kumizh tree' when burnt yields the whitest possible ash; mention is made by certain 'rock art enthusiasts' that this ash is one of the ingredients in the semi-solid white ochre used to draw the very ancient 'cave paintings,' as old as 3,000 to 5,000 years or more; found in the dense forests of Tamil Nadu. Gmelina arborea wood
Chemistry
s, such as 6" - bromo - isoarboreol, 4-hydroxysesamin, 4,8-dihydroxysesamin, 1,4-dihydroxysesamin, 2-piperonyl-3-hydroxymethyl-4--4-hydroxytetrahydrofuran and the 4-O-glucoside of 4-epigummadiol, can be isolated from the heartwood of Gmelina arborea. The parent compounds are arboreol or gmelanone. Umbelliferone 7-apiosylglucoside can be isolated from the root. Five constituents, isolated from the heartwood of G. arborea, -7′-O-ethyl arboreol, -paulownin, -gmelinol, -epieudesmin and -β-sitosterol, show antifungal activity against Trametes versicolor.
