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Melaleuca quinquenervia (Cav.) S.T.Blake

Syn.: M. cajuputi Auct.
M. leucadendron Auct.
Myrtaceae
Cajeput

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 unpublished.


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

Uses

Source of oil of Cajeput or Tea Tree Oil, used as a mosquito repellent, effective also against lice and fleas. The tea-tree oil serves as a solvent and cleaning agent. Dissolving caoutchouc, it creates a good varnish. In dentistry, it is used to relieve the pain of dry sockets. The oil is used as a flavor component in foods (baked goods, candy, condiments, dairy desserts, meat and meat products, nonalcoholic beverages, relishes) and in creams, detergents, lotions, perfumes, and soaps (Leung, 1980). Bark serves in lieu of cork as an insulating material, also used in floats, life belts, and stuffing cushions, mattresses, and pillows (Duke, 1984b). Years ago, the tree was recommended for salt swamps to subdue "malarial vapors." In India, sheets of cajeput bark were historically employed for sacred writing. The bark is useful in packing tropical fruits. The leaf infusion has been used as a tea. Steeping the flower in water is said to impart an agreeable sweetness to the water. The wood, durable under ground and water, is valued for boats, cabinetry, carving, crossties, fencerails, flooring, gunstocks, mine braces, pilings, posts, rafters, railway sleepers, ships and wharves.

Folk Medicine

Reported to be antiseptic, astringent, carminative, diaphoretic, emollient, rubefacient, sedative, stimulant, sudorific, and vermifuge, cajeput is a folk remedy for acne, bronchitis, bruise, cholera, cold, colic, cough, diarrhea, earache, eczema, gout, headache, hiccup, inflammation, laryngitis, malaria, myalgia, neuralgia, paralysis, pharyngitis, pityriasis, pleuritis, pneumonia, psoriasis, rheumatism, rhinitts, scabies, scurvy, skin ailments, sore throat, spasms, sprains, toothache, and tumors (Duke and Wain, 1981). Burmese mix cajeput oil with camphor for gout. Indochinese use the oil for arthritis and rheumatism, inhaling the oil for colds and rhinitis. Cambodians use the leaves for dropsy. Indonesians apply the oil externally for burns, cramps, colic, earache, headache, pain, skin disease, and toothache. Softened bark is applied to boils as a suppurative. New Guinea natives rub the oil on the body for malaria. Filipinos use the leaves for asthma. Indonesians use the fruit for stomach disorders. Malayans use the oil as pain killer and stomachic, dropping a bit onto sugar lumps for cholera and colic (Duke, 1984b). In India, the oil is used internally as an expectorant in chronic bronchitis and laryngitis. Overdoses cause gastrointestinal irritation. Acts as an anthelmintic, especially against roundworms.

Chemistry

Leaves contain ca 1.3% essential oil with 14–65% cineole (or eucalyptol), 1-pinene, and terpineol and aldehydes. Besides these, the oil contains 1-limonene, 3,5,-dimethyl-4-6-di-0-methylphloroacetophenone, dipentene, nerolidiol, sesquiterpenes, azulene, sesquiterpene alcohols, valeraldehyde, and benzaldehyde. The bark contains betulinic acid (melaleucin) (Duke, 1984b). Oleanolic- and ursolic-acids, quercimeritrin, isoquercitrin, kaempferol-3-glucoside, kaemp-ferols-7-glucoside, and gallic acid derivatives are also reported (List and Horhammer, 1969–1979). Silica content of the wood varies from 0.2–0.95%.

Toxicity

Overdoses of the oil may induce gastroenteritis, kidney inflammation, and disturbance of the nervous system. Even small amounts may cause skin eruptions in sensitive persons (Morton, 1966). Although the vapors emanating from the tree may repel insects and the trees may serve as a "super Air-Wick", Morton (1966) adduces evidence to show that the volatile properties may also irritate the human respiratory system. Morton even suggests that eating cajeput honey may build up immunity in cajeput-sensitive individuals. Mitchell and Rook (1979) say that contact with branches, fruits, and roots, even the volatile emanations, can produce dermatitis. The oil can produce dermatitis and folliculitis when used for massage. According to Leung (1980), "Available data indicate it to be nontoxic ... Has been approved for food use ([[section]]172.510)."

Description

Resiniferous evergreen tree to 30 m tall, 1 m diameter, with whitish papery bark, often exfoliating. Leaves alternate, dull green, narrowly lanceolate, oblanceolate, or lance-elliptic, 5–20 cm long, 5–35 mm wide, apically and basally acute, entire, pli-nerved, aromatic, the petiole 2–4 mm long. Flowers ramiflorous, between or below groups of leaves in "bottlebrush spikes" 4–15 cm long, often producing apical foliaceous shoots following flowering. Calyx with 5 rounded lobes <2 mm long, and 5 somewhat longer whitish petals, ca 30 filiform stamens and inferior 2–4 celled ovary with many ovules. Capsules sessile, crowded along the branches, with many minute narrow brown seeds <2 m long.

Germplasm

Reported from the Australian, Hindustani, and Indonesia-Indochina Centers of Diversity, cajeput, or cvs thereof, is reported to tolerate acid sulphate soils, brackish sites, drought, fire, heavy soils, light frost, limestone, low pH, poor soil, salt spray, sand, tin tailings, waterlogging, weeds, and wind. Morton (1966) discusses several of the confusing variations in this species and genus. (2n = 22)

Distribution

Native from eastern Australia through Malaysia and Burma, now widely introduced, e.g. in Africa, Central America, Florida, Hawaii, India, Philippines, Puerto Rico, South America, and the West Indies.

Ecology

Ranging from Subtropical Dry to Wet through Tropical Dry Forest Life Zones, cajeput is reported to tolerate annual precipitation of 6.4 to 40.3 dm (mean of 4 cases = 22.2), annual temperature of 21.3 to 25.°4C (mean of 4 cases = 24.0), and pH of 5 to 7.7 (mean of 3 cases = 6.6) ( Duke, 1978, 1979). Commonly forms forest communities on swampy ground; in Java, Sumatra, and Borneo, forms brackish swamp forests immediately behind the mangroves and great savannas in Buru and Ceram. Its thick flaky bark makes it fire resistant. In Burma it sometimes occurs as shrub or small tree on edge of tidal forests. In Annam and Queensland, it is found on sand dunes as shrub up to 1 m tall, or shrubs of 1–2 m tall in amphibious scrub. Common in gray podsolic depressions in sandstone outcropping areas with Eucalyptus species. Occasionally on calcareous gravelly soils near waterholes.

Cultivation

Propagated by seed, but cuttings of immature wood root easily in sand, laid horizontally. Seeds are scattered on damp seedbed, placed in shade or covered with damp burlap or sphagnum moss. Stratification has been reported to retard germination. Seedlings may attain 1–2 m height a year. Once established, trees are extremely vigorous and tough, crowding out other plants and difficult to exterminate by cutting or burning. It is rarely cultivated for essential oil because of the enormous quantity of leaf material available from wild-growing trees.

Harvesting

Leaves, harvested throughout the year, are cut from shrubs or low trees which are not more than 6 months old. Fresh leaves and terminal branchlets yield, on steam-distillation, the volatile oil. The commercial product is usually green due to its being distilled in copper containers. Distillation often takes place in field stills similar to those used for producing American eucalyptus oils (Reed, 1976). Seven year rotations have been suggested in Malaysia. Coppices readily.

Yields and Economics

Leaves and branchlets yield 1–1.5%, sometimes up to 1.8%, of essential oil. Of five trees studied in Florida, this one was projected to lead the others by far in dry matter yields, at 28.5 MT/ha of 9.4 for slash pine, 9.0 for sand pine, 8.3 for casuarina, and only 5.6 MT/ha for Eucalyptus (Smith and Dowd, 1981). At spacings of 1 x 2 m, M. leucadendron yields 5,500 kg leaves/yr, at 1 x 2.5 m, 3,500 kg. Webb et al. (1980) put the annual wood production at 10–16 m3/ha. During this century, oil of cajeput is imported into India mainly from France and Netherlands, up to 10 MT/yr. Main producers of the oil are in the East Indies. Much of the crude oil is shipped to other countries where it is refined and resold. When Morton (1966) published her paper, tea-tree oil was twice as costly as Eucalyptus oil. It takes ca 1 man-hour to harvest 8.5 kg leaves, and 405 man-hours/ha (Fenton et al., 1977).

Energy

According to the phytomass files (Duke, 1981b), standing biomass of Melaleuca in Cambodia, LAI 7.1, was ca 172 MT/ha. Fenton et al. (1977) however put the stem biomass of natural stands at only 7.4 MT/ha. Moderately heavy (740–785 kg/m3 air dry, 410 kg/m3 oven dried), the wood is said to be an excellent fuel, the chief firewood of Malacca, exuding resin as it burns. The average heat values (kj/kg) of melaleuca wood, bark, terminal branches, and foliage were 18,422, 25,791, 19,301, and 20,139, respectively. The heat of combustion of melaleuca bark is unique because it is comparable with that of some coals at 25,000 kj/kg, the highest figure yet determined for tree material. This unique characteristic is due to the presence of a great amount of fatty substances in the bark. The densities (g/cm3) of stemwood and stembark are approximately 0.51 and 0.19, respectively. The green moisture contents averaged 114% for stemwood and 131% for stembark. The average ash contents of stemwood and stembark are 0.7 and 2.7%, respectively. The fuel quality of melaleuca stemwood and stembark varies significantly among trees (Wang et al., 1982).

Biotic Factors

Browne (1968) lists the following as affecting M. leucadendron: (Fungi) Fomes lignosus. (Angiospermae) Loranthus sp. (?). (Crustacea) Sesarma spp. (Lepidoptera) Bathrotoma constrictana, Metara elongata. (Mammalia) Lepus crawshayi. Fenton et al (1977) list the following fungi: Cylindrocladium macrosporum, C. pteriolis, Phellinus senex (causing heart rot), Phytophthora cinnamomi, Pleomassaria melaleucac, and Rigidiporus lignosis on this or closely related species. In Hawaii, the black twig borer Xylosandrus compactus, has been associated with plantation mortality. The foliage is unattractive to browsing livestock.

References

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