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Gmelina arborea Roxb

Verbenaceae
Gmelina, White teak

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Description
  5. Germplasm
  6. Distribution
  7. Ecology
  8. Cultivation
  9. Harvesting
  10. Yields and Economics
  11. Energy
  12. Biotic Factors
  13. References

Uses

The wood is one of the best timbers of the tropics, useful for particle board, plywood core stock, pit props, matches, and saw timber for light construction, furniture, general carpentry, and packing. Also used in carriages, carvings, musical instruments, and ornamental work. Graveyard tests indicate that the untreated timber may last 15 years in contact with the soil. With pulping properties superior to most hardwood pulps, gmelina has been planted by the millions, e.g. in the Rio Jari region of Brazil to feed a 750 MT/day kraft pulp mill. In Gambia there are dual purpose plantings, for firewood and for honey. It is often planted as an ornamental avenue shade tree. The wood makes a fairly good charcoal. According to Little (1983), the leaves are harvested for fodder for animals and silkworms; the bittersweet fruits were once consumed by humans.

Folk Medicine

According to Hartwell (1967–1971), the root decoction is used in folk remedies for abdominal tumors in India. Reported to be anodyne, demulcent, lactagogue, refrigerant, stomachic, and tonic, gmelina is a folk remedy for anasarca, anthrax, bilious disorder, bites, blood disorders, cholera, colic, convulsions, delirium, diarrhea, dropsy, dyspepsia, epilepsy, fever, gout, ,gravel, headache, hemorrhage, intoxication, madness, phthisis, ratbites, rheumatism, rinderpest, septicemia, smallpox, snakebite, sores, sorethroat, splenitis, stomachic, swelling, and urticaria (Duke and Wain, 1981). Deeming the fruits alterative, aphrodisiac, astringent, diuretic, and tonic, Ayurvedics prescribe them for alopecia, anemia, consumption, leprosy, strangury, thirst, and vaginal discharges; the flowers for blood disorders and leprosy; the root, deemed anthelmintic, apertif, laxative, and stomachic, for abdominal pains, burning sensations, fever, hallucinations, piles, thirst and urinary discharges (Duke, 1984 in ed.).

Chemistry

The drupes are reported to contain butyric acid traces of tartaric acid and resinous and saccharine matter, the latter two also in the roots, which contain traces of benzoic acid.

Description

Deciduous tree 12–30 m high and 60–100 cm in diameter. Bark light gray or gray-yellow, smooth, thin, somewhat corking, becoming brown and rough; twigs stout, often slightly 4-angled. Leaves opposite, broadly ovate, 10–20 cm long, 7–13 cm wide; base with 2–4 glands beneath, acuminate, entire, with 3 or 5 main veins from near base and 2–5 pairs of side veins, underneath velvety with yellow-brown hairs. Petiole 5–12 cm long, hairy. Cymes paniculate at ends of twigs, 15–30 cm long, branched, densely hairy. Flowers many, short-stalked, nodding, 4 cm long, densely hairy. Calyx bell-shaped, 5 mm long, 5-toothed; corolla bright orange-yellow or brownish-yellow, with short narrow tube, 2-lipped; stamens 4 in 2 pairs inserted near base of tube. Pistil with elliptical 4-celled ovary having 1 ovule in each cell. Stigma often slightly 2–4-forked. Drupes ovate or pyriform, 2–2.5 cm long, smooth, becoming orange-yellow, pulpy, with large egg-shaped stone, having 1–4 cells. Seeds 1–4 (Little, 1983).

Germplasm

Reported to tolerate disease, drought, fire, heat, laterite, light frosts, and slope. Although casting a dense shade itself, it is intolerant of shade as a seedling (Little, 1983).(2n = 36, 38)

Distribution

Native to tropical moist forest from India, Burma, and Sri Lanka to southern China, Gmelina is widely introduced, e.g. in Brazil, Gambia, Honduras, Ivory Coast, Malaysia, Malawi, Nigeria, Panama, Philippines, and Sierra Leone.

Ecology

Estimated to range from Tropical Very Dry to Wet through Subtropical Very Dry to Wet Forest Life Zones, gmelina is reported or estimated to tolerate annual precipitation of 7 to 45 dm (NAS, 1980a), annual temperature of 20 to 26°C, and pH of 6 to 8. It can tolerate a 6–7-month dry season. Grows on many soils, acidic laterites to calcareous loams, doing poorly on thin or poor soils with hardpan, dry sands, or heavily leached acidic soils, well-drained basic alluviums.

Cultivation

Seeds, retaining their viability for only about 12 months, will benefit from soaking if rain or irrigation is not expected. Direct seeding is cheap but tubed seedlings are also outplanted, sometimes intercropped with beans, cashew, corn, peanuts, and tobacco. For fuelwood, spacing at 2 x 2 m is recommended, wider spacings for timber plantations. For the first year or so, weeding is necessary, but the canopy is soon dense, like the litter layer, quickly arresting the weed growth.

Harvesting

Trees coppice well, with 5-year coppice rotations for fuel, longer rotations for timber.

Yields and Economics

The NAS (1980a) reports annual increments; >30 m3/ha, on fertile sites. Rotations of 5–8 years may produce 20–35 m3. Occasionally trees may start dying out at only 10 years age.

Energy

Destructive distillation of the wood yields 31.8% charcoal, 47.1% total distillate, 37.1% pyroligneous acid, 10.0% tar, 2.4% pitch, and losses, 4.47% acids, 3.42% esters, 2.38% acetone, and 1.28% methanol on a dry weight basis. The non-condensable gases (1.88 ft3/lb) contain 59% CO2, 31.75% CO, 4.5% methane, 4.15% H, and 0.6% unsaturated hydrocarbons. Many of these have energetic potential (C.S.I.R., 1948–1976). Reynolds and Lawson (1978) concluded that the heating value of Gmelina wood was less than that from the local eucalypts. Although the calorific values of the samples studied were almost identical (4.53 mcal/kg and 4.54 respectively), the DM contents were 45 and 56%. The fresh weight of Gmelina firewood brought in cubic-meter lots was significantly correlated with butt size. The NAS (1980a) suggests 4.8 mcal/kg for the sapwood, spec. grav. 0.42–0.64. The charcoal burns well, without smoke, leaving a lot of ash. The Wealth of India (C.S.I.R., 1948–1976) puts the calorific value at 4.763 mcal (8,547 BTU) with silica free ash of 1.54%. In a 10-year-old Philippine stand, the aboveground biomass was 127 MT/ha, leaf biomass was 1.4 MT, leaf litter ca 5.2 MT, constituting ca 62% of the total litter. Annual productivity was 18 MT/ha. Annual stem increment was about 10 MT/ha or 30 M3/ha, little influenced by the age of the stand over the first 15 years (Kawahara et al., 1981). Akachuku's data (1981) show annual yields of 20–50 m3/ha/yr but he cites other studies on poor sandy soil yielding only 7, on laterites only 18; on the best of savanna sites 25, on rainforest sites 31–36, on Malaysia sites 28–38, and on Philippine sites 36 m3. MAI in 7-year trees was 32 m3 (15 MT) to 47 m3 (23 MT)/ha (Akachuku, 1981).

Biotic Factors

Cattle may eat the foliage and bark; seeds and foliage are consumed avidly by rabbits and deer. In Latin America, the leaves are gathered by the leaf-cutter ants. In India, other insects may defoliate the plant. Calopepla may defoliate, while the borers, Dihamnus and Alicide, may damage the trees. The "machete disease", Ceratocystis fimbriata, is sometimes severe in moister climates. Poria rhizomorpha may cause stem and root diseases in wet situations with heavy soils. Browne (1968) lists the following as affecting Gmelina arborea: (Fungi) Armillaria mellea, Cercospora ranjita, Fomes roseus, Polyporus baudni, Poria rhizomorpha, Sclerotinia rolfsii, Trametes straminea. (Angiospermae) Tapinanthus sp. (Mollusca) Limicolaria aurora. (Myriapoda) Odontopyge sp. (Coleoptera) Alcidodes ludificator, Apion angulicolle, A. armipes, Apophyllia chloroptera, A. sulcata, Calopepla leayana, Dihammus cervinus, Empecamenta calabarica, Lagria villosa, Lixus camerunus, L. spinimanus, Macrocoma candens, podagrica dilecta, Prioptera punctipennis, Xyleborus fornicatus. (Hemiptera) Agaeus pavimentatus, Anoplocnemis tristator, Chunrocerus niveosparsus, Dysdercus superstitiosus, Tingis beesoni, Trioza fletcheri. (Isoptera) Coptotermes curvignathus, C. niger, Macrotermes goliath. (Lepidoptera) Acrocercops telestis, Endoclita undulifer, Eupterote geminata, E. undata, Evergestis aureolalis, Gonodontis clelia, Indarbela quadrinotata, Metanastria hyrtaca, Phostria caniusalis, Psilogramma menephron, Sahyadrassus malabaricus, Selepa celtis, Xyleutes ceramica. (Orthoptera) Heteropternis thoracica, Kraussaria angulifera, Phaneroptera nana, Phymateus viridipes, Zonocerus elegans. (Mammalia) Axis axis, Strepsiceros strepsiceros, Sylvicarpa grimmia, Thryonomys swinderianus, Tragelaphus scriptus.

References

Complete list of references for Duke, Handbook of Energy Crops
Last update Wednesday, January 7, 1998 by aw