598

13: Spices

Syzygium polyanthum (Wight) Walpers

Repert. bot. syst. 2: 180 (1843).

MYRTACEAE

2n = unknown

Eugenia polyantha Wight (1831), Eugenia nitida Duthie (1878), Eugenia balsamea Ridley (1922).

Salam, Indonesian bay-leaf (En). Indonesia: salam (general), manting (Javanese), ubar serai (Sumatra). Malaysia: samak, kelat samak, serah. Cambodia: pring srâtoab. Thailand: dokmaeo (peninsular), daengkluai (central), mak (Chumphon, Ranong). Vietnam: s[aws]n thuy[eef]n.

Syzygium polyanthum is widely distributed in Burma (Myanmar), Indo-China, Thailand, Malaysia, and Indonesia (Java, Sumatra, Kalimantan).

The aromatic leaves of salam, either fresh or dried, are used as a spice in many South-East Asian meat, fish, rice and vegetable dishes. Its use is comparable to that of laurel leaves (bay-leaves) in European cuisine. The leaves are added early on and are left to cook with the dish, as the flavour develops only gradually. Ripe fruits are edible, although slightly astringent.
Leaf and bark extracts are used medicinally against diarrhoea. Pounded leaves, bark and roots are applied as poultices against itches. The bark is used for tanning fishing-nets and for dyeing bamboo matting brown-red (for further blackening the matting is subsequently immersed in mud). Timber of Syzygium polyanthum belongs to the trade group 'kelat', which is a medium-weight to heavy hardwood. It is used for house building and furniture.

No statistics are available on production and trade. Production and local trade is considerable because, for example in Indonesia, young leaves are sold on almost all local markets and by street vendors, and the bark is extensively used for dyeing purposes.

Dried salam leaves contain about 0.17% essential oil. Eugenol and methyl chavicol are important components. Ethanolic extracts of the leaves show antifungal and antibacterial activity, methanolic extracts show strong nematicidal activity against the pine-wood nematode Bursaphelenchus xylophilus.
The wood is pale brown to pinkish-brown with a purplish tinge; the density is 540-790 kg/m³ at 15% moisture content.

In South-East Asia, salam leaves are used as a substitute for the laurel leaves of European cuisine. Salam leaf oil can be distinguished from laurel leaf oil by its optical rotation, salam leaf oil being dextro-rotatory, laurel leaf oil laevo-rotatory.

Medium-sized tree up to 30 m tall with dense crown, bole up to 60 cm in diameter; bark surface fissured and scaly, grey. Leaves opposite, simple, glabrous; petiole up to 12 mm long; blade oblong-elliptical, narrowly elliptical or lanceolate, 5-16 cm x 2.5-7 cm, with 6-11 pairs of secondary veins distinct below and a distinct intramarginal vein, dotted with minute oil glands. Inflorescence a panicle, 2-8 cm long, usually arising below the leaves, sometimes axillary, but trees flower very profusely; flowers sessile, bisexual, regular, fragrant, white, in threes on ultimate branchlets of the panicle; calyx cup-shaped, about 4 mm long, with 4 broad persistent lobes; petals 4, free, 2.5-3.5 mm long, white; stamens numerous, arranged in 4 groups, about 3 mm long; disk quadrangular, orange-yellow. Fruit a 1-seeded berry, depressed globose to globose, up to 12 mm in diameter, dark red to purplish-black when ripe.

Syzygium polyanthum may flower as soon as 3 years old. Flowering and fruiting are more or less year-round. The flowers last for 4-7 days and are usually pollinated by beetles and butterflies. Branches break off easily during strong winds.

Syzygium polyanthum is widely distributed and locally common as understorey tree in lowland primary and secondary forests, also in thickets, bamboo forest and teak plantations, in Java up to 1000 m, in Sabah up to 1200 m, and in Thailand up to 1300 m altitude.

Salam is propagated by seed, cuttings or air layering. Wildlings can be collected from under adult trees.
Seed loses its viability very rapidly and after 4-6 weeks it hardly germinates. Seed should be sown fresh from the fruit, on the surface of loose soil and under shade. It should not be buried, as this seriously reduces the germination percentage. Germination is rapid, starting 1-3 weeks after sowing, and is complete after 5-12 weeks.
Natural regeneration is generally profuse and seedlings can survice under shade for several years. Wildlings should be hardened off in a nursery before being planted.
Trees are planted in the field at a spacing of 6 m x 6 m. However, in forestry a spacing of 2 m x 3 m is used because 6 m x 6 m is considered too wide for timber production, as it gives rise to an unfavourable stem form and undesired branching.
Syzygium polyanthum is often used for underplanting in forest plantations (teak, pine, kauri) to reduce excessive development of weeds. The leaves decay relatively slowly and provide large quantities of mulch.

Salam is a common home-garden tree, receiving little specific attention. Regular pruning seems to be tolerated.

The tip-boring caterpillar Argyroploce mormopa may cause damage.

Leaves are harvested by pruning the tree or by cutting off the tips of twigs.

No information is available on the yield of leaves.
In pure timber plantations on fertile soils in Java, mean annual increments of 7-22 m³ of wood per ha at different tree ages and at different tree spacings have been obtained. In natural forest in Riau, a mean annual increment of 10.5 m³ of wood per ha has been measured.

The leaves must be properly dried before storage.

Some ex situ germplasm conservation has been carried out in Malaysia, but there are no known extensive germplasm collections or breeding programmes.

The lack of information on the spice aspects of the salam tree is in great contrast with its widespread use in South-East Asian cuisine. Its competitiveness vis-à-vis laurel would be an interesting subject for study.

Mackeen, M.M., Ali, A.M., Abdullah, M.A., Nasir, R.M., Mat, N.B., Razak, A.R. & Kawazu, K., 1997. Antinematodal activity of some Malaysian plant extracts against the pine wood nematode, Bursaphelenchus xylophilus. Pesticide Science 51: 165-170.
Mohamed, S., Saka, S., ElSharkawy, S.H., Ali, A.M. & Muid, S., 1996. Antimycotic screening of 58 Malaysian plants against plant pathogens. Pesticide Science 47: 259-264.
Noorma Wati Haron, Laming, P.B., Fundter, J.M. & Lemmens, R.H.M.J., 1995. Syzygium Gaertner. In: Lemmens, R.H.M.J., Soerianegara, I. & Wong, W.C. (Editors): Plant Resources of South-East Asia No 5(2). Timber trees: Minor commercial timbers. Backhuys Publishers, Leiden, the Netherlands. pp. 441-474.
Pohan, H.G. & Susanto, E., 1995. Mempelajari pengaruh kondisi proses penyulingan serta lama pelayuan daun terhadap hasil dan karakteristik minyak daun salam (Eugenia polyantha Wight) [Study of the effect of distillation condition and withering time on the yield and characteristics of 'salam' leaf oil (Eugenia polyantha Wight)]. Warta-IHP (Industri Hasil Pertanian) 12(1-2): 69-73.

S. Sardjono

Sardjono, S., 1999. Syzygium polyanthum (Wight) Walpers. In: de Guzman, C.C. and Siemonsma, J.S. (Editors): Plant Resources of South-East Asia No 13: Spices. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea