6524

17: Fibre plants

Artocarpus elasticus Reinw. ex Blume

Bijdr. fl. Ned. Ind.: 481 (1825) ('elastica').

MORACEAE

2n = 56

Artocarpus blumei Trécul (1847), Artocarpus kunstleri King (1888).

Wild breadfruit (En). Brunei: danging, tebagan, terap hutan. Indonesia: benda (Javanese, Sundanese), teureup (Sundanese), terap (Sumatra, Kalimantan). Malaysia: terap nasi (Peninsular), terap (Sarawak), terap togop (Sabah). Thailand: oh, ka oh, tuka (peninsular).

Artocarpus elasticus is native to Burma (Myanmar), Thailand, Malaysia, Brunei, Indonesia (Irian Jaya excluded) and the Philippines (Palawan). It is also cultivated, for instance in Malaysia and Indonesia (Java, Kalimantan).

The bast (inner bark) of Artocarpus elasticus is traditionally made into cloth ('barkcloth'), for instance by aborigines in Sarawak. This cloth has been used to make shirts, loincloths, jackets, blankets and house walls. The bast also serves for making string, fishing nets and lines, carrying straps on baskets and mats. In Indonesia it has been made into bandages. It has been suggested as a raw material for paper making. The leaves are used for thatching and for making partitions in longhouses and temporary huts. In Malaysia Artocarpus elasticus fibre is an attribute in rice- and wedding-ceremonies and healing rituals.
Peeled shoot tips may be eaten raw or cooked and the fleshy perianth is edible as well. Ripe fruits are sometimes eaten, but they often have a bad smell. The seeds are eaten roasted or fried. The latex is used as birdlime. In Indonesia the leaves mixed with rice are taken against tuberculosis, and the latex against dysentery. The timber is used for light construction and for making boats, for instance in Java and Brunei.

Artocarpus elasticus fibre and its products are used and sold locally and seldom traded on a large commercial scale; production and trade statistics are not available.

The ultimate fibres in the bast of Artocarpus elasticus are (9-)18(—27) mm long, which is comparable to hemp (Cannabis sativa L.), and about 33(—44) µm wide. The cellulose content (Cross and Bevan method), calculated on a moisture-free base, is about 64%. The bast of old trees is less pliable than that from young ones, and therefore they have different names. In Malaysia young trees are called 'kelabit' and old trees 'talm'. In Tapanuli (Sumatra) young trees are called 'uwalang' and old trees 'torop'.
The average length of the ultimate fibres in the wood is 1.7 mm. The wood contains 59% holocellulose, 41% a-cellulose, 13% pentosans, 28% lignin and 1% ash. The solubility is 6.4% in alcohol-benzene, 6.2% in hot water and 16.9% in a 1% NaOH solution. It has a density of 365—545 kg/m³ at 15% moisture content. With 15% active alkali a sulphate pulp yield of 51% has been obtained, with a kappa number of 20.6 and good paper making properties. The paper made from this pulp had a bulk density of 1.3—1.4 cm³/g, a tear index of 11.8 mNm²/g, a breaking length of 9.1—11.9 km and a stretch of 4.0—4.7%.
Seven prenyl flavonoids (artelastin, artelastochromene, artelasticin, artocarpesin, cyclocommunin, artelastocarpin and carpelastofuran) have been isolated from the wood of Artocarpus elasticus. They have shown moderate to strong in vitro activity against 3 human cancer cell lines (MCF-7, TK-10 and UACC-62), with artelastin having the most potent activity. Artelastin, artelastochromene, artelasticin and artocarpesin have also shown anticomplementary activity.
The 1000-seed weight is 500—850 g.

To obtain barkcloth or cordage other Artocarpus species may be used in place of Artocarpus elasticus, such as Artocarpus blancoi (Elmer) Merr., Artocarpus rubrovenius Warb. and Artocarpus tamaran Becc. (see minor species). Barkcloth has also been obtained from Antiaris toxicaria Lesch. and Broussonetia papyrifera (L.) L'Hér. ex Vent. Nowadays barkcloth has almost entirely been replaced by cotton (Gossypium spp.). In Sarawak Artocarpus elasticus string is replaced by string made from the leaves of Curculigo latifolia Dryand., but the latter is less strong and durable.

An evergreen, monoecious tree, up to 45(—65) m tall; bole branchless for up to 30 m, up to 1.2(—2) m in diameter, with buttresses up to 3 m high; outer bark dark grey, smooth to slightly scaly, upon wounding exuding a white, thick latex; inner bark (bast) yellowish to pale brown; sapwood yellowish-white; twigs 1—2 cm in diameter, bearing ring-like stipular scars, short hispid. Leaves spirally arranged, stiffly leathery, in juvenile trees 2—3-times pinnatifid and up to 2 m long, in adult trees simple; stipules amplexicaul, lanceolate, 6—20 cm long, hispid-pubescent with yellow to red-brown hairs; petiole 4—10 cm long; blade ovate to elliptical, 15—60 cm x 10—35 cm, base rounded or cuneate, margin entire or shallowly crenate, apex acuminate; midrib raised above, lateral veins 12—14 pairs and flat and distinct above but prominently raised below, upper surface appressed hispid, lower surface bullate and hispid-pubescent. Inflorescence unisexual, capitate, solitary, axillary; numerous flowers densely packed together, embedded in the receptacle, the perianths enclosing a single stamen or ovary, usually mixed with abundant, stalked, interfloral bracts. Male head on peduncle 4—7.5 cm long, cylindrical, 6—15(—20) cm x 1.5—2.5 cm, with distinct deep grooves, yellow; perianth tubular, 0.8 mm long, bilobed at apex, appressed pubescent; stamens up to 0.9 mm long. Female head with bifid styles exserted to 1 mm. Fruit a syncarp on a 7—12 cm long peduncle, cylindrical, up to 17 cm x 10 cm, yellow-brown, covered by closely set, fleshy, whitish, short-hispid processes ('spines') of 2 lengths, the longer flexuous and solid, 10—18 mm x 1—1.5 mm, the shorter ones narrowly conical, perforate, 4 mm x 1 mm; interfloral bracts scattered between the processes, slenderly stalked and with funnel-shaped upper parts; fruiting perianths numerous, the proximal free region fleshy and white. Seed (the thin, horny pericarp) ellipsoidal, 10 mm x 6 mm. Seedling with hypogeal germination.

Germination of Artocarpus elasticus starts in the third week after sowing and growth is relatively fast. The average height after 2 years of growth is 6—7 m, and after 7 years 11—12 m, with an average diameter of about 15 cm, i.e. a mean annual diameter increment of over 2 cm. Juvenile plants have deeply-lobed leaves (twice or thrice pinnatifid); as the tree grows the new leaves are less deeply cut until only simple adult leaves are produced. Artocarpus elasticus may be deciduous in regions with a dry season, such as the eastern coast of Peninsular Malaysia and its northern region. In Java flowers have been collected in January, August and November, and fruits in January. Artocarpus elasticus is probably wind-pollinated, the male inflorescences producing clouds of pollen. The fruits are eaten by monkeys and squirrels, which probably play an important role in seed dispersal. Artocarpus elasticus coppices freely, with the leaves on the coppice shoots having lobed leaves like those produced on juvenile trees.

Artocarpus J.R. Forster & G. Forster contains about 50 species and is distributed from Pakistan, India and Sri Lanka throughout South-East Asia to southern China, Taiwan, the Solomon Islands and Australia. It is divided into subgenus Artocarpus, with spirally arranged leaves having large amplexicaul stipules, and subgenus Pseudojaca Trécul, with alternate and distichous leaves having small non-amplexicaul stipules. Artocarpus elasticus belongs to subgenus Artocarpus.
Artocarpus elasticus is the most important source of fibre in the genus, not because its fibre is the best, but because it is good enough and readily available from the forest. Fibre for cordage and cloth is also obtained from several Artocarpus species treated in the PROSEA volumes 2 and 5(2): Artocarpus altilis (Parkinson) Fosberg (synonym Artocarpus communis J.R. & G. Forster), Artocarpus heterophyllus Lamk, Artocarpus integer (Thunb.) Merr. (synonyms: Artocarpus champeden (Lour.) Stokes, Artocarpus integrifolia L.f.), Artocarpus scortechinii King and Artocarpus sericicarpus Jarrett. Artocarpus lakoocha Roxb. is used for cordage in India.
Artocarpus elasticus is absent in the Philippines except for in Palawan and published information on Artocarpus elasticus in other parts of the Philippines probably refers to Artocarpus sericicarpus (some major differences with Artocarpus elasticus are: leaves are more thinly coriaceous and sometimes slightly scabrid above, never short-hispid; male head 3.5—10 cm x 1.5—2 cm; female head subglobose, 4.5 cm x 4 cm; syncarp ellipsoidal to cylindrical, 8.5 cm x 5 cm, with long processes 20—35 mm x 0.5—1 mm, short ones 3—6 mm x 1 mm). Some authors, however, consider Artocarpus sericicarpus to be a synonym of Artocarpus elasticus. Some information published on Artocarpus elasticus in Borneo seems to refer to Artocarpus tamaran Becc. (characteristics: leaves with 17—23 pairs of lateral veins; juvenile leaves deeply pinnatifid with sessile pinnae and narrowly winged rachis; surface of the male head bears short, irregularly cylindrical projections with pilose tips; processes on the syncarp up to 10 mm x 0.5 mm and covered by recurved hairs), and is therefore not included in the present treatment.

Artocarpus elasticus is found in evergreen and semi-deciduous forest, both primary and secondary, up to 1500 m altitude.

Artocarpus elasticus can be propagated by seed. Seeds germinate readily (85%) when sown fresh, but germination decreases to 60% for seeds stored for 1 week and to 0% for those stored for 2 weeks. Seeds remain viable when kept inside the fruit, so storage may be slightly prolonged in this way. Artocarpus elasticus is sometimes planted in villages, for instance in Indonesia, but more often wild plants are utilized.

Artocarpus elasticus trees usually have a diameter at breast height of more than 10 cm when they are cut to obtain the bast. For the production of string the Kenyahs in Sarawak fell young saplings or coppice shoots. To obtain latex the trunks are commonly scored in herring-bone fashion.

In Sarawak the bast of Artocarpus elasticus is separated from the tree and outer bark, and then soaked in clean water to make it supple, after which it is stretched and dried. Next it is repeatedly pounded with a wooden beater (called 'tutuk' or 'pemalu' in Sarawak), rolled up first on one side and then on the other. It is soaked in clean water again and the whole process may be repeated. Most often, however, once is enough. The resulting coarse blanket is made into cloths. To make cordage, bast strips are usually pounded and twisted. To obtain string, the Kenyahs in Sarawak cut the felled stems into pieces 1.5—2 m long and the bark is stripped off in pieces 2—3 cm wide or more. The bast is peeled from the outer bark and dried in the sun for 2—3 days, after which it is reddish-brown. The material can be stored in this form. When string is needed, the bast material is divided into fine strands for plaiting. For mat-making in Tapanuli (Sumatra) the bark is removed from felled trees, after which the outer bark is removed and the bast is pounded until it is supple. Then it is dried and cut into strips, which are woven into mats, together with split rattan. In Padang Lawas (Sumatra) the bast is pounded, dried, submerged in water for 5 minutes, folded, pressed between 2 planks and cut into strips. Alternatively, the pounded bast is submerged in running water for one night, dried and then cut into strips.

No germplasm collections or breeding programmes of Artocarpus elasticus are known to exist.

Though Artocarpus elasticus is at present only locally used as a source of cordage and cloth, there is some prospect for an increase of its importance, because the long ultimate fibres make the bast fibre useful (e.g. as a substitute for hemp), the wood has good pulping and paper making characteristics, and compounds isolated from the wood have shown anticancer activity.

Cidade, H.M., Nacimento, M.S., Pinto, M.M.M., Kijjoa, A., Silva, A.M.S. & Herz, W., 2001. Artelastocarpin and carpelastofuran, two new flavones, and cytotoxicities of prenyl flavonoids from Artocarpus elasticus against three cancer cell lines. Planta Medica 67(9): 867—870.
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Kochummen, K.M., 2000. Artocarpus. In: Soepadmo, E. & Saw, L.G. (Editors): Tree flora of Sabah and Sarawak. Vol. 3. Sabah Forestry Department, Forest Research Institute Malaysia & Sarawak Forestry Department, Kepong, Malaysia. pp. 187—212.
Logan, A.F., Balodis, V., Tan, Y.K. & Phillips, F.H., 1984. Kraft pulping properties of individual species from Sarawak forest resources. 2. Mixed dipterocarp forest species. Malaysian Forester 47(1—2): 89—115.

S.P. Teo & R.E. Nasution

Teo, S.P. & Nasution, R.E., 2003. Artocarpus elasticus Reinw. ex Blume. In: Brink, M and Escobin, R.P. (Editors): Plant Resources of South-East Asia No 17: Fibre plants. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea