Dyera costulata

Dyera costulata, the jelutong, is a species of tree in the family Apocynaceae. It grows to approximately 60 metres (200 ft) tall with diameters of 2 metres (5 to 6 ft), or even to 80 m (260 ft) tall with diameters to 3 m (10 ft), and boles clear and straight for 30 m (90 ft). It grows in Malaysia, Borneo, Sumatra and southern Thailand. Its natural distribution is scattered locales in low-elevation tropical evergreen forest. In addition, jelutong can be tapped for latex and from the 1920s through the 1960s, jelutong latex was an important source of chewing gum. Jelutong has been traditionally overharvested, and is a threatened species in many areas. It is a protected species in parts of Malaysia and Thailand. The tree is grown commercially for timber. Sawdust from this species has been known to cause allergic dermatitis.

Description

A big tree. It grows 60 m high and spreads 9 m wide. It is 27 m until the first branch. The trunk can be 2 m wide. The leaves are simple and oval. They are 7-18 cm long. They are in rings near the ends of branches. The flowers are 3.5 mm across and white. They are in rings. The fruit can be 32 cm long. They are brown, dry, woody and curved. They split along one side when ripe. The seeds are flat and winged.

Edible Uses

No edible uses are known.

Traditional Uses

The sap or gum is chewed.

This uses section is brief — help expand it

Medicinal Uses

The resinous fruits are used for medicinal purposes.

Distribution

A tropical plant. It grows on flat and undulating land in a variety of soils. It grows up to 400 m above sea level. It suits hardiness zones 11-12.

Where It Grows

Asia, Australia, Brunei, Indochina, Indonesia, Malaysia, SE Asia, Singapore, Thailand,

Cultivation

Plants can be grown from seed of cuttings.

Propagation

The small seed has a viability of less than one year. Pre-treatment is unnecessary, though soaking in water for 12 hours before sowing can speed germination. Germination rates are typically good at 80–90%. Seedlings can be potted up once the first pair of leaves has emerged and planted out when they reach 30cm tall.

Other Uses

Latex tapped from the trunk is used in the production of chewing gum, celluloid, linoleum, and electric cable insulation, and also serves as an admixture for cement, paints, and paper. Specialty uses of the latex include pattern making in foundry work, drawing boards, pencils, picture frames, dowels, carving, blackboards, wooden toys, clogs, brush handles, battery separators, furniture parts, door knobs, ceilings, partitioning, matchsticks, matchboxes, and packing cases. The resinous fruits can be used as torches and are also burnt to repel mosquitoes. The roots serve as a cork substitute. The heartwood is creamy white to pale straw coloured with frequent large latex canals, not differentiated from the sapwood. The grain is mostly straight with a moderately fine, even texture; slightly lustrous, with a distinctive slight sour odour. The wood is very light and soft, not durable, and susceptible to fungi, dry wood borers, and termites. It seasons rapidly with little risk of checking or distortion and is stable once dry. It works easily with hand and machine tools, though tools must be kept very sharp for a smooth finish; latex can clog sawteeth, and nailing and screwing are poor, though gluing is satisfactory. The wood is excellent for carving and is used for patterns, pencils, matches, matchboxes, boxes and crates, furniture components, interior joinery, panelling, drawing boards, blockboard, and veneer.

Production

The tree is tapped for its latex.

Notes

They are tropical plants. It is an important timber tree.

Synonyms

Also Known As

Jeletung gunung, Pantung, Pohon jelutung, Pulu

References (14)

• Ambasta, S.P. (Ed.), 2000, The Useful Plants of India. CSIR India. p 186
• Boer, E. & A. B. Ella, eds. 2000. Plants producing exudates. In: Faridah Hanum, I. & L. J. G. van der Maesen, eds., Plant Resources of South-East Asia (PROSEA). (Pl Res SEAs) 18:65.
• Brouk, B., 1975, Plants Consumed by Man. Academic Press, London. p 375
• Burkill, I.H., 1966, A Dictionary of the Economic Products of the Malay Peninsula. Ministry of Agriculture and Cooperatives, Kuala Lumpur, Malaysia. Vol 1 (A-H) p 889
• Cundall, P., (ed.), 2004, Gardening Australia: flora: the gardener's bible. ABC Books. p 519

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