777

18: Plants producing exudates

Canarium L.

Amoen. Acad. 4: 143 (1759).

BURSERACEAE

x = unknown; Canarium ovatum: 2n = 46

Major species and synonyms
— Canarium asperum Benth., Journ. Bot., Lond. 2: 215 (1843), synonyms: Canarium legitimum Miq. (1859), Canarium villosum Benth. & Hook.f. ex Fern.-Vill. (1880), Canarium zollingeri Engl. (1883).
— Canarium hirsutum Willd., Sp. pl. 4(2): 760 (1806), synonyms: Canarium hispidum Blume (1823), Canarium multipinnatum Llanos (1851), Canarium subcordatum Ridl. (1920).
— Canarium indicum L., Amoen. Acad. 4: 143 (1759), synonyms: Canarium mehenbethene Gaertn. (1791), Canarium zephyrinum Duchesne (1836), Canarium moluccanum Blume (1850), Canarium amboinense Hochr. (1904).
— Canarium luzonicum (Blume) A.Gray, U.S. Expl. Exped., Phan.: 374 (1854), synonyms: Canarium carapifolium Perkins (1904), Canarium polyanthum Perkins (1904), Canarium oliganthum Merr. (1915).
— Canarium ovatum Engl., in: A.DC., Monogr. Phan. 4: 110 (1883), synonyms: Canarium pachyphyllum Perkins (1904), Canarium melioides Elmer (1911).
— Canarium vulgare Leenh., Bull. Bish. Mus. 216: 31, fig. 13 (1955), synonym: Canarium commune L. (1767) p.p.

— Canarium asperum: Indonesia: damar jahat (Sulawesi), damar itam (Ambon), kessi (Sumbawa). Philippines: pagsahingin (Filipino), sulusalungan (Bisaya), anteng (Iloko).
— Canarium hirsutum: Indonesia: ki bonteng (West Java), kanari jaki (northern Sulawesi), mede-mede (Moluccas). Malaysia: kedondong (general), damar degun (Peninsular), kambayau burong (Sabah). Philippines: dulit (general), bakayan (Panay Bisaya), hagushus (Bikol).
— Canarium indicum: Indonesia: kanari ambon (Sundanese), kanari ternate (northern Sulawesi), kanari bagea (Moluccas). Papua New Guinea: red canarium (general), galip (Pidgin), lawele (New Britain).
— Canarium luzonicum: Philippines: piling-liitan (Filipino), belis (Tagalog), malapili (Bikol).
— Canarium ovatum: Pilinut (En). Philippines: pili, pilaui (general), liputi (Tagalog).
— Canarium vulgare: Java almond (En). Amande de Java (Fr). Indonesia: kanari (general), ki tuwak (Java), jal (Ambon). Malaysia: pokok kenari, rata kukana (Peninsular).

Canarium consists of about 80 species and is distributed in the Old World tropics, from tropical Africa to tropical Asia, northern Australia and the Pacific. The main centre of diversity lies in the Malesian area. Canarium asperum is found in the Philippines, Borneo, the Lesser Sunda Islands, Sulawesi, the Moluccas, New Guinea and the Solomon Islands. Canarium hirsutum occurs in Peninsular Malaysia, the Philippines, Sumatra, Java, Borneo, Sulawesi, the Moluccas, New Guinea, the Caroline Islands (Palau) and the Solomon Islands. Canarium indicum is found in Sulawesi, the Moluccas, New Guinea, Vanuatu, the Solomon Islands and the Santa Cruz Islands, while Canarium luzonicum and Canarium ovatum are both restricted to the Philippines (where the latter is often cultivated for its nuts). Canarium vulgare occurs naturally in the Kangean and Bawean Islands, the Lesser Sunda Islands, Sulawesi, the Moluccas and New Guinea and is planted throughout the tropics for its fruits.

'Manila elemi', also known under the name 'brea branca' meaning white pitch, is the oleoresin which exudes from the bark of Canarium trees when they are tapped or wounded. Canarium luzonicum is by far the most important species for commercial production of Manila elemi. In commerce the essential oil distilled from Manila elemi is mainly used for fragrance applications (such as soap and perfumes) and as a base for liniment. Manila elemi still finds occasional use as an ingredient in lacquers and varnishes, where it gives toughness and elasticity to the dried film. Moreover, it is applied in medicinal plasters and in ointments where a slight stimulant and antiseptic is required. It has also been used for the manufacture of printing inks, surface coatings for textiles and paper, incense, linoleum, oilcloth, waterproofing compositions and as an insect repellent in cabinets. Locally it is used in torches, as a firelighter, to caulk boats and to dress transmission belts and conveyors. In China it has been applied for the manufacture of transparent paper for window panes. Manila elemi has also been used for fixing iron tools in their wooden handles and it is used medicinally as stimulant, rubefacient and anti-rheumatic and for the treatment of respiratory ailments.
In Peninsular Malaysia, the dark brown resin, known locally as 'damar sengai' is most probably from Canarium hirsutum and has been found to be suitable in spirit varnish. This hard resin is likely to be confused with resins from Dipterocarpaceae, the 'damars'. Torches used to be prepared by kneading the very sticky resin on the ground until enough dirt has been incorporated to make it stiff, and then rolling it into shape.
Several Canarium species (e.g. Canarium indicum, Canarium luzonicum, Canarium ovatum) are known for their edible kernels and the edible pulp of their fruits and provide valuable fat and protein in the diets of many people. Sometimes oil is extracted from the fruit pulp or the kernels and used for cooking and lighting; young shoots (e.g. of Canarium ovatum) are occasionally eaten as a salad. The hard and thick shell enclosing the seeds makes an excellent fuel for cooking. Canarium trees make an excellent windbreak and are well suited as ornamentals. Their wood falls within the 'kedondong' timber trade group and is used for indoor construction and as a firewood.

Manila elemi is the only elemi traded internationally nowadays. Annual exports from the Philippines were somewhat erratic for the period 1988—1993, but the average is almost 300 t. In the three years 1996—1998, 353 t, 162 t and 221 t of Manila elemi were exported. France is the largest importer, accounting for 75% of the total exported from the Philippines. Germany is the second biggest market, followed by Japan. The market for Manila elemi can probably sustain levels of around 200—300 t annually. Prices for Manila elemi fluctuate more than those for other resins. The free-on-board (FOB) export prices were US$ 1.67—2.08 per kg for the period 1990—1993. By mid-1995, London-based importers reported a doubling of the price compared with the previous year and quoted prices of US$ 4.20—4.50 per kg. The FOB export price in 1996 was US$ 2.68/kg.

When fresh, Manila elemi is oily and pale yellow or greenish, resembling crystallized honey in consistency, but on exposure to air it loses some of the volatile constituents and hardens. It has a balsamic odour and a spicy, rather bitter taste. Soft and hard elemi are distinguished. 'Soft elemi' is aromatic and soft and is produced by Canarium luzonicum, Canarium asperum, Canarium indicum, Canarium ovatum and Canarium vulgare. The 'hard elemis' are only slightly aromatic and are darker in colour (e.g. Canarium hirsutum). Manila elemi is completely soluble in alcohol and ether. The crude oleoresin contains 25—30% essential oil, which can be obtained by steam distillation. The scent of the oil of Canarium luzonicum resembles that of fennel (Foeniculum vulgare Mill.) and mace (Myristica fragrans Houtt.). The scent of the essential oil from Canarium indicum and Canarium vulgare resembles eugenol, the major component of the essential oil of clove (Syzygium aromaticum (L.) Merr. & L.M.Perry). Manila elemi consists primarily of resenes together with some resin acids and volatile terpenes; its approximate composition is 0.4—1% insoluble matter, 17—25% volatile terpenes, 1—2% non-volatile terpenes, 56—61% resenes, 15—18% resin acids and 1—3% moisture. The saponification number is 28.5, the acid number 18.5 and the ester number is 10.0. The chemical composition of Manila elemi oil is approximately: 56% limonene, 18% 'ALFA'-phellandrene, 6% elemol, 6% sabinene, 3% terpinolene, 2% elemicin and 3% ß-phellandrene, but the composition can vary a great deal and 'ALFA'-pinene, ß-pinene, myrcene, 'DELTA'-carene, 'DELTA'-terpinene and geraniol have also been demonstrated in the oil. It has the following properties: specific gravity 0.952, optical rotation ('ALFA'_D³⁰) —2°, refractive index (n_D³⁰) 1.497. The essential oil from Canarium indicum oleoresin also contains phellandrene. On an experimental scale Manila elemi oil at 5% concentration has proved to be capable of eliminating a number of wood-destroying fungi. At 20% it caused 88% mortality in drywood termites (Cryptotermes spp.) and 25% mortality in powder post beetles (Lyctus spp.). It shows significant antibacterial activities against Escherichia coli and Staphylococcus aureus.
The exudate from Canarium asperum, known as 'sahing' in the Philippines, contains 11% essential oil with p-cymol as principal constituent.
Damar sengai (from Canarium hirsutum) forms stalactite-like masses which are uniformly free from dirt. The surface of the very hard resin has a vitreous appearance; it has a melting range of 120—135°C. It is almost non-acid (has an acid number of 0.9) and has a very low saponification number of 8. The resin dissolves completely in benzene, chloroform, kerosene, petroleum ether and turpentine and 25% soluble in alcohol, 39% soluble in acetone and 44% soluble in ether. It is the only hard resin completely soluble in petroleum ether.

Dioecious, evergreen trees up to 35(—60) m tall, rarely shrubs; bole up to 120(—200) cm in diameter, with or without buttresses; bark surface smooth to flaky, scaly or dippled, often greyish, inner bark sometimes laminated, pinkish or reddish-brown, with strong resinous odour and clear sticky or oily exudate; pith of twigs usually containing vascular strands. Leaves arranged spirally, imparipinnate, with (1—)3—17(—27) opposite and often toothed leaflets; base of petiole and of petiolules often swollen; stipules usually present, entire to fimbriate. Inflorescence terminal or sometimes axillary, paniculate or sometimes reduced to a raceme or a spike; flowers actinomorphic, 3-merous, functionally unisexual but vestiges of the opposite sex present; calyx cupular with deltoid lobes, nearly always densely hairy inside; petals free, usually imbricate, creamy white, with inflexed tips; stamens 6, or rarely 3, free to entirely connate; disk intrastaminal, 6-lobed, often pilose; ovary superior, 3-celled, each cell with 2 axillary ovules, stigma sessile or short-stalked. Fruit a cylindrical drupe, seated on a persistent enlarged calyx, hairy or glabrous, ripening blue-black, glaucous at first, very wrinkled when dry; endocarp stony (pyrene), with 1—2 cells slightly to nearly entirely reduced. Seed with palmatifid to 3-foliolate and variously folded cotyledons. Seedling with epigeal germination; first 2 leaves simple and opposite, entire or toothed, subsequent leaves alternate and eventually arranged spirally and imparipinnate.
— Canarium asperum. A tree up to 35 m tall, bole 100 cm in diameter, buttresses prominent; stipules subpersistent to caducous, narrow; leaves with 1—13 leaflets; leaflets ovate to elliptical, 4—30 cm x 2—10 cm, apex tapering to acute or bluntly acuminate, margin entire but serrulate to dentate in young plants, glabrous to pilose on the midrib above and the veins below, with (7—)12—15(—20) pairs of secondary veins; inflorescence very variable, spicate to narrowly paniculate; flowers 3—7 mm long, stamens 6; fruit ovoid to subglobose, circular to slightly trigonous in cross-section, 9—14 mm x 4—11 mm, glabrous. This is a highly variable species.
— Canarium hirsutum. A tree up to 32(—48) m tall, bole 60(—200) cm in diameter, buttresses usually absent or very small; stipules absent or present, inserted at the base of the petiole, narrow; leaves with 9— 27 leaflets, rachis thick with sharp edges; leaflets ovate to lanceolate, 5—45 cm x 2—15 cm, apex gradually to rather abruptly short-acuminate, margin entire, variably pubescent to glabrous, with 12—30 pairs of secondary veins; inflorescence axillary, male one paniculate, female one subracemose; flowers 10—13 mm long, stamens 6; fruit ovoid, circular in cross-section, 20—63 mm x 17—45 mm, usually with irritating reddish-brown hairs. This is also a highly polymorphic species.
— Canarium indicum. A tree up to 40 m tall, bole 100 cm in diameter, buttresses up to 1 m tall; stipules persistent, rarely inserted on the petiole, ovate to oblong, large and prominently dentate; leaves with 7—15 leaflets; leaflets oblong to lanceolate, 5—28 cm x 2—11 cm, apex gradually to distinctly acuminate, margin entire, glabrous, with (8—)10—15(—20) pairs of secondary veins which are slightly sunken above and prominent below; inflorescence terminal, broadly paniculate; male flowers about 10 mm long, female ones up to 15 mm long, stamens 6; fruit ovoid, circular to slightly triangular in cross-section, 35— 60 mm x 15—30 mm, glabrous.
— Canarium luzonicum. A tree up to 35 m tall, bole 100 cm in diameter; stipules caducous to subpersistent, inserted on the base of the petiole, orbicular; leaves with 7—11 leaflets; leaflets lanceolate to oblong, 6—25 cm x 2—11 cm, apex gradually and long blunt-acuminate, margin entire, glabrous, with 14— 18 pairs of secondary veins; inflorescence axillary, paniculate; male flowers 2.5—4 mm long, female ones 6 —8 mm long, stamens 3—6 in the male and 6 in the female flower; fruit broadly ovoid to ellipsoidal, circular to bluntly triangular in cross-section, 25—38 mm x 15—20 mm, glabrous.
— Canarium ovatum. A tree up to 35 m tall, bole 100 cm in diameter, without buttresses; stipules persistent, inserted on the petiole, deltoid to lingulate; leaves with 5—9 leaflets; leaflets ovate to elliptical, 4—24 cm x 2—12 cm, apex distinctly acuminate, margin entire, glabrous, with 8—12 pairs of secondary veins; inflorescence axillary, narrowly paniculate to nearly racemose; flowers up to 13 mm long, stamens 6; fruit ovoid to ellipsoidal, triangular in cross-section, 35—63 mm x 20—28 mm, glabrous.
— Canarium vulgare. A tree up to 45 m tall, bole often gnarled in cultivated specimens, up to 70 cm in diameter, buttresses up to 3 m tall; stipules caducous, inserted at the leaf axil, oblong; leaves with (5—)9—11 leaflets; leaflets ovate to oblong, 5—16 cm x 2—10 cm, apex gradually to distinctly long-acuminate, margin entire, glabrous, with 12—15 pairs of secondary veins which are slightly prominent below; inflorescence terminal, broadly paniculate; male flowers 5 mm long, female ones 6—7(—12) mm long, stamens 6; fruit ovoid, circular to slightly trigonous in cross-section, 35—50 mm x 15—30 mm, glabrous.

Canarium trees flower mainly in the dry season and fruit during the wet season, although many species do not have definite flowering or fruiting seasons. Canarium vulgare flowers and fruits throughout the year in West Java and fruits are ripe in February— March and October. Canarium ovatum flowers in March—June in the Philippines. In both male and female trees the order of blooming of the flowers in an inflorescence is basipetal, that is blossoming proceeds from the top downwards. Anthesis in both male and female flowers takes place between 4 and 6 p.m. At anthesis the flowers emit a fragrant odour; this suggests that they are principally pollinated by insects. Fruit set in flowers pollinated at anthesis averages almost 90% but no fruits develop in flowers pollinated 24 h after anthesis. The fruits are dispersed by fruit-eating pigeons and monkeys, and are occasionally eaten and dispersed by bats.

Canarium asperum and Canarium hirsutum are widespread in Malesia and their variability is large - several subspecies and varieties have been distinguished. Canarium indicum and Canarium vulgare are closely related - for a long time they were distinguished as separate species. Canarium luzonicum and Canarium ovatum are also closely related. Other Canarium species from which the exudate has been used, mainly in traditional applications such as torches, for caulking boats and for fixing tools in handles are: Canarium balsamiferum Willd., Canarium decumanum Gaertn., Canarium copaliferum A.Chev., Canarium littorale Blume, Canarium oleosum (Lam.) Engl., Canarium pseudodecumanum Hochr. and Canarium sylvestre Gaertn.

Canarium occurs in primary and secondary rain forest, generally up to 500 m altitude, but occasionally up to 1800 m. Canarium vulgare occurs locally and gregariously in rather dry primary rain forest on limestone, up to 1200 m altitude; other Canarium species usually occur scattered.

Canarium trees are usually planted for fruit production and for ornamental purposes, but not for resin or oleoresin. Canarium can be propagated by seed, and seedlings may be prepared as stumps before planting. Vegetative methods of propagation are practised for the fruit species, e.g. budding and grafting techniques are used for Canarium ovatum. There are 200—1350 seeds of Canarium ovatum per kg and about 145 dry stones (each stone containing 1—2 seeds) of Canarium vulgare per kg. Without temperature control air-dry Canarium vulgare seeds can be stored for several months to 1.5 years.

Tapping of Canarium trees provides a livelihood for people in parts of the Philippines where these trees are common, namely Bicol Peninsula (Luzon Island), Quezon Province, Marinduque, Masbate (Ticao and Burias Islands), Romblon (Sibuyan Island) and parts of Samar. In Quezon Province many subsist by tapping Canarium trees. Apart from the actual tapping, the wild trees are not managed.

It has been suggested that because of the resinous material it contains Canarium is relatively free from diseases and pests. Anthracnose of young seedlings has been observed in Canarium ovatum, but this is easily controlled by fungicides.

Canarium luzonicum trees are tapped by making horizontal incisions (2 cm high and 30 cm long) in the bark with a sharp bush knife and a wooden mallet. The diameter of the trees tapped is 20—60 cm. Subsequent strips about 1 cm high are removed above the previous cuts. This 'rechipping' is done at intervals of 2—7 days. Tapping is continued upwards, as high as a person can reach. A second face may be opened, provided that at least one third of the circumference of the tree is left intact. An improved tapping method is now advocated in the Philippines. This consists of cleaning and scraping the bark which is to be tapped. The first horizontal incision should not be more than 60 cm from the ground, 2 cm high and 15 cm long. It is important to control the depth of cutting precisely, using a wooden mallet so as not to damage the cambium and hence impair the vigour of the tree. A plastic receptacle should be fixed to the tree and the portion tapped, and the receptacle should be covered by a polythene sheet to prevent contamination with water, insects and debris. The exudate is collected every week and rechippings of 3—5 mm wide are made immediately above the previous incision. A second tapping panel should be at least twice the length of the incision (30 cm) apart. Trees under 30 cm in diameter should not be tapped at all. Tapping is strictly prohibited from April to June as trees shed their leaves and as a consequence resin production is insufficient. Mortality of trees often occurs 5 years after the first tapping, due to very deep incisions, overtapping and too frequent rechipping. In trials new rechippings were sprayed with 15—45% sulphuric acid, but the yield did not significantly increase. In Indonesia, resin exuded spontaneously from Canarium indicum and Canarium vulgare (presumably to be due to reduced vigour of the tree) used to be collected. It was not collected by tapping the lower part of the stem or the roots, as this reduced fruit yield.
Tapping to obtain damar sengai has never been reported.

In Quezon province in the Philippines, an annual yield of resin of 1—4 kg/tree is obtained, but estimates go up to 12 kg of 'uncleaned resin' per tree.

Three classes of Manila elemi exist for the domestic Philippine market and for export trade, although the designations are not always adhered to. Class 1 is the palest material, with two grades: clean (grade A) and non-clean (grade B). Class 2 is the more yellowish material; it also has grades A and B for clean and non-clean material. Class 3 is a mixture of classes 1 and 2. The softer Manila elemi is of higher quality, reflecting its higher essential oil content compared with the harder elemi's. The essential oil can be obtained by steam distillation. As the freshly distilled oil is liable to resinify and polymerize on standing, distillation is normally carried out in the importing country, where the oil can be formulated soon after preparation. A resinoid is also sometimes prepared by solvent extraction of the crude elemi. Resin for export is packed in polythene bags, to prevent seepage or evaporation of the Manila elemi oil. The bags are then packed in wooden crates which weigh about 25 kg when full. Formerly, Manila elemi used to be purified by solution in benzene, filtering off impurities such as bark and dirt, and distilling the filtrate to yield a white resin of leafy appearance.

Natural populations of Canarium (particularly Canarium luzonicum) should be screened to determine the provenance and tree-to-tree variation in oleoresin yield and composition. It is recommended to start a germplasm collection.

There has already been development of improved varieties of Canarium for fruit and nut production. Research on resin production should be complementary to research on fruit and nut production, as the latter is the main purpose of cultivation.

Canarium ovatum and other exudate-producing Canarium species are already grown as sources of fruits and nuts; integration with resin tapping would be a welcome development, provided resin production does not adversely affect fruit production.

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E.C. Fernandez

Fernandez, E.C., 2000. Canarium L.. In: Boer, E. and Ella, A.B. (Editors): Plant Resources of South-East Asia No 18: Plants producing exudates. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea