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Pittosporum resiniferum Hemsl.

Pittosporaceae
Petroleum nut (English) Hanga (Philippine)

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 unpublished.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

Called petroleum nut because of the fancied resemblance of the odor of the fruit's oil to that of petroleum, the fruits, even green ones, burn brilliantly when ignited. Hence they are used like torch nuts or candlenuts for illumination in the bush. Dihydroterpene (C10H18) is used in perfumes and medicines. Heptane (C7H16) is a component of gasoline, and has been suggested as a possible component of paint and varnish (Anonymous, 1981c).

Folk Medicine

Fruit is used as a panacea by Philippine traditionalists, especially, however, for abdominal pain. The oleoresin is used to treat muscular pains and skin diseases (Perry, 1980). The nut decoction is used for colds. Crushed nuts are mixed with coconut oil as a relief for myalgia. Altschul (1973) quotes from a 1947 Sulit herbarium specimen, "Petroleum gas extracted from the fruit is medicinal for stomachache and cicitrizant."

Chemistry

The volatile oil of the fruit is reported to contain "dihydroterpene and heptane, which is a cardiac glycoside." (Perry, 1980). The Horticultural and Special Crops Laboratory at Peoria analyzed an accession of fruit, and identified, from its "squeezings", constituents passing through a gas chromatographic column, heptane (about 45% of the elutents) nonane, a-pinene or b-ocimene, b-pinene, myrcene, and unidentified materials. According to Nemethy and Calvin (1982) the essential oil (8-10% of fruit weight) contains myrcene (40%) and a-pinene (38%) in ± equal quantities (P. undulatum's contains mostly limonene). The two components n-heptane (5%) and n-nonane (7%) are minor components.

Description

Aromatic tree to 30 m tall, but probably smaller in its elfin forest habitat (perhaps even epiphytic); fruiting when only 6–12 m tall. Leaves aromatic, coriaceous, entire (possibly evergreen), thickest above the middle, pinnately nerved, with a short acumen at the tip. Flowers fragrant, white, clustered on the stems. Fruits average 25 mm in diameter (12–43). Each fruit has 5–72 seeds (average 31), the seeds ranging from 1–40 mm, averaging 3 mm. The seeds are about as close to hexahedral and prismatic as any I have seen, being quite angular, black to blackish gold, often still surrounded by a gummy or resinous endocarp.

Germplasm

The FORI Director in the Philippines is actively collecting superior germplasm in the high mountains of Bontoc and Benguet where they abound, especially in elfin forests.(2n = 24)

Distribution

In the Philippines, petroleum nut is locally known in Benguet as apisang, abkol, abkel, and langis; in the Mountain Province, dael and dingo, and in Abra, sagaga. It abounds in Mt. Pulis, Ifugao, and is reported from the headwaters of the Agno and Chico River Basins. Also in the Bicol Provinces, Palawan, Hindoro, Nueva Ecija, and Laguna Provinces. It is being cultivated at FORI's Conifer Research Center, Baguio City.

Ecology

Petroleum nut is reported to range from 600–2,400 m elevation, usually in elfin or Benguet Pine Forest. Average of 7 climatic data sites where the Pittosporum grows, was close to 1,000 m, the range from ca 550 to 2,000 m. Whether or not it can stand frost, dry heat, and drought is questionable. Frequently, species of elfin forests have very narrow ecological amplitudes and do not thrive in other vegetation types. Results of transplants and trials are unavailable to me now. Reportedly seed were introduced once, at least to Hawaii. Thanks to Professors Ludivina S. de Padua, S.C. Hales, and Juan V. Pancho of the Philippines, we now have a fairly good idea of the ecosystematic amplitudes of the Pittosporum, an energy plant that has captured the imagination of many. Professor de Padua checked off all the climatic data points (from our climatic data base) at which Pittosporum resiniferum was growing, prior to its widespread introduction for potential energy studies elsewhere in the Philippines. Ranging from Tropical Dry to Moist through Subtropical Forest Life Zones, the petroleum nut grows where the annual precipitation ranges from 15 to more than 50 dm (mean of 36 cases = 27 dm), annual temperature from 18–28°C (mean of 17 cases = 26°C). Of 17 cases where both temperature and rainfall data were available to us, 13 would suggest Tropical Moist Forest Life Zone, three would suggest Tropical Dry, and one would suggest Subtropical Rain Forest Life Zones.

Cultivation

Seeds and cutting can be used to propagate the tree. Seeds may lose their vitality rather rapidly. According to Juan V. Pancho (personal communication, 1982), "from my experience, the seed lost its viability after one month storage."

Harvesting

Currently, seeds are harvested from the wild.

Yields and Economics

A single fruit yields 0.1–3.3 ml, averaging about 1.3 ml. In general, the bigger the fruit, the larger the seed, and the greater the oil content (Veracion and Costales, 1981). It is reported (Anonymous, 1981) that a single tree from Mount Mariveles, Bataan, yielded 15 kg green fruits, which yielded 80 cm3 of oil. The residue, ground up and distilled with steam, yielded 73 cm3 more. Another report gave 68 g per kg fresh nuts, suggesting about 1 kg oil per tree yielding 15 kg (Anonymous, 1981c). Currently seed are being sold at $2.00 per gram in 5-gram lots (ca 40 seed per g) by the FORI Seed Officer, Forest Research Institute, College, Laguna, Philippines.

Energy

The plant was discovered as a hydrocarbon source just after 1900, but based on the previous paragraph, it seems it would take 1,000 trees per ha to get one MT oil per hectare from the fruits. Perhaps the resin in the leaves, twigs, etc. would equal or exceed this; figures are not yet available. The oil derived from the fruits is quite sticky and rapidly turns resinous when laid thin. In an open dish, it burns strongly, although with a sooty flame (Anonymous, 1981). C.A. Arroyo (1981) notes that for home use as fuel, "the husk of African oil palm nuts could be much better than the petroleum nut that emits sooty smoke and strong smell." Recently, I heard rumors that President Marcos was encouraging each Philippine farmer to plant five trees in the hopes that they could obtain 300 liters of oil therefrom, per year. I saw nothing about this at the Philippine exhibit at the World's Fair in June 1982. However, if yields of 60 liters of oil per tree are possible, the tree should certainly be examined! In the January 1981 issue of Canopy, Generalao (1981) lists petroleum nut at the top of a long list of potential oil seeds including Pongamia pinnata, Sterculia foetida, Terminalia catappa, Sindora supa, Calophyllum inophyllum, Canarium luzonicum, Aleurites moluccana, Aleurites trisperma, Mallotus philippensis, Barringtonia asiatica, Sindora inermis, Pithecellobium dulce, Tamarindus indica, Chisocheton cumingianus, Jatropha curcas, and Euphorbia philippensis to help the Philippines solve their energy problem (importing 85%). Presidential Decree 1068 declares the imperative acceleration of research on energy alternatives. Speaking in that same issue of Canopy, an editorial notes that in 1978 FORI concluded the flammable element in petroleum nut is volatile, evaporating quickly like acetone. Some chemists believe admixing another element will stabilize the compound. One seed catalog (Anonymous, ca 1983) has very optimistic notes about the plant. "The Gasoline Tree produces masses of apricot-sized orange fruits which when cut and touched with a match leap into flame and burn steadily. The fruits contain 46% of gasoline type components (heptane,dihydroterpene, etc.), which are found in extensive networks of large resin canals. If planted the estimated yield would be about 45 tons of fruit or 2500 gallons of 'gasoline' per acre per year."

Biotic Factors

No data available.

References

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