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Aleurites moluccana (L.) Willd.

Syn.: Aleurites triloba Forst.
Croton moluccanus L.
Euphorbiaceae
Candlenut oil tree, Candleberry, Varnish tree, Indian or Belgaum walnut

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 unpublished.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

Seed yields 57–80% of inedible, semi-drying oil, liquid at ordinary temperatures, solidifying at -15°C, containing oleostearic acid. Oil, quicker drying than linseed oil, is used as a wood preservative, for varnishes and paint oil, as an illuminant, for soap making, waterproofing paper, rubber substitutes and insulating material. Seeds are moderately poisonous and press cake is used as fertilizer. Kernels when roasted and cooked are considered edible; may be strung as candlenuts. Oil is painted on bottoms of small crafts to .protect against marine borers. Tung oil, applied to cotton bolls, stops boil weevils from eating them. Also prevents feeding by striped cucumber beetle.

Folk Medicine

Bark used on tumors in Japan. The oil is purgative and sometimes used like castor oil. Kernels are laxative stimulant, and sudorific. The irritant oil is rubbed on scalp as a hair stimulant. In Sumatra, pounded seeds, burned with charcoal,are applied around the navel forcositiveness. In Malaya, the pulped kernel enters poultices for headache, fevers, ulcers, and swollen joints. In Java, the bark is used for bloody diarrhea or dysentery. Bark juice with coconut milk is used for sprue. Malayans apply boiled leaves to the temples for headache and to the pubes for gonnorhea

Chemistry

The oil cake, containing ca 46.2% protein, 4.4% P2O5, and 2.0% K2O, is said to be poisonous. A toxalbumin and HCN have been suggested. Bark contains ca 4–6% tannin. Oil also contains glycerides of linolenic, oleic and various linoleic acids. Per 100 g, the seed is reported to contain 626 calories, 7.0 g H2O, 19.0 g protein, 63.0 g fat, 8.0 g total carbohydrate, 3.0 g ash, 80 mg Ca, 200 mg P, 2.0 mg Fe, 0 mg beta-carotene equivalent, 0.06 mg thiamine, and 0 mg ascorbic acid.

Description

Medium-sized tree, up to 20 m tall, ornamental, with widespreading or pendulous branches; leaves simple, variable in shape, young leaves large, up to 30 cm long, palmate, with 3–7 acuminate lobes, shining, while leaves on mature trees are ovate, entire, and acuminate, long-petioled, whitish above when young, becoming green with age, with rusty stellate pubescence beneath when young, and perisiting on veins and petiole; flowers in rusty-pubescent panicled cymes 10–15 cm long; petals 5, dingy white or creamy, oblong, up to 1.3 cm long; ovary 2-celled; fruit an indehiscent drupe, roundish, 5 cm or more in diameter, with thick rough hard shell making up 64–68% of fruit, difficult to separate from kernels; containing 1 or 2 seeds. Fl. Apr.–May (Sri Lanka).

Germplasm

Reported from the Indochina-Indonesia Center of Diversity, Aleurites moluccana or cvs thereof is reported to tolerate high pH, low pH, poor soil, and slope (Duke, 1978) (2n = 44, 22)

Distribution

Native to Malaysia, Polynesia, Malay Peninsula, Philippines and South Seas Islands; now widely distributed in tropics. Naturalized or cultivated in Malagasy, Sri Lanka, southern India, Bangladesh, Brazil, West Indies, and Gulf Coast of United States.

Ecology

Candlenut trees thrive in moist tropical regions, up to 1,200 m altitude. Ranging from Subtropical Dry to Wet through Tropical Very Dry to Wet Forest Life Zones, Aleurites moluccana is reported to tolerate annual precipitation of 6.4 to 42.9 dm (mean of 14 cases = 19.4) annual temperature of 18.7 to 27.4°C (mean of 14 cases = 24.6) and pH of 5.0 to 8.0 (mean of 7 cases = 6–4). (Duke,1978, 1979)

Cultivation

Usually propagated from seed, requiring 3–4 months to germinate. Seedlings planted 300/ha. Once established, trees require little to no attention.

Harvesting

Bears two heavy crops each year, harvested when mature. Kernels adhere to sides of shell and are difficult to separate.

Yields and Economics

In plantations yields are estimated at 5–20 MT/ha nuts, each tree producing 30–80 kg. Oil production varies from 15 to 20% of nut weight. Most oil produced in India, Sri Lanka and other tropical regions is used locally and does not figure into international trade. In the past, oil has sold for 12–14 pounds per ton in England. According to the Chemical Marketing Reporter (June 8, 1981), tung oil prices (then ca 0.65/lb.) are likely to rise in the near future if demand remains adequate and Argentinean and Parguayan suppliers pressure the U.S. market by charging high prices for replacement oil. U.S. imports for the first quarter of 1981 were 58% higher than 1980, despite the absence of Chinese tung from the market.

Energy

Nut yields at 80 kg/tree, spaced at 200 trees per hectare, would suggest 16 MT/ha/yr, about 20% of which (3 MT) would be oil, suitable, with modification, for diesel uses, the residues for conversion to alcohol or pyrolysis. Fruit yields may range from 4–20 MT/ha/yr. Commercial production of oil yields 12–18% of the weight of the dry unhulled fruits, the fruits being air-dried to ca 12–15% moisture before pressing (Univ. Fla. Bul. 221, 1935). Oil yields as high as 3, 100 kg/ha have been reported. The pomace contains 4.5–5% oil. This suggests that the "chaff factor" might be ca 0.8. As of June 15, tung oil was $0.65/lb, compared to $0.38 for peanut oil, $1.39 for poppyseed oil, $0.33 for linseed oil, $0.275 for coconut oil, $0.265 for cottonseed oil, $0.232 for corn oil, and $0.21 for soybean oil (Chemical Marketing Reporter, June 15, 1981). At $2.00 per gallon, gasoline is roughly $0.25/lb.

Biotic Factors

Following fungi are known to attack candlenut-oil tree: Cephalosporium sp., Clitocybe tabescens, Fomes hawaiensis, Gloeosporium aleuriticum, Physalospora rhodina, Polyporus gilvus, Pythium ultimum, Sclerotium rolfsii, Sphaeronema reinkingii, Trametes corrugata, Xylaria curta, Ustulina deusta. Nematodes include Meloidogyne sp. (Golden, p.c. 1984).

References

Complete list of references for Duke, Handbook of Energy Crops
Last update Friday, December 19, 1997