Dipterocarpus gracilis (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Dipterocarpus gracilis Blume

Protologue: Bijdr. fl. Ned. Ind. 5: 224 (1825).

Synonyms

• Dipterocarpus pilosus Roxb. (1832),
• Dipterocarpus marginatus Korth. (1841),
• Dipterocarpus vernicifluus (Blanco) Blanco (1845).

Vernacular names

• Brunei: keruing kesat
• Indonesia: keruing keladan (general), wuluk bulan (Java), damar kacawai (southern Sumatra)
• Malaysia: keruing kesat (general), keruing kesugoi (Sabah)
• Philippines: panau (general), agan-an (Bikol), lalian (Tagalog)
• Burma: kanyin, kanyin-ni
• Thailand: yang-sian (general), yang-daeng (south-eastern), yung-hua-waen (peninsular).

Distribution

Bangladesh, Burma, Thailand, Peninsular Malaysia, Sumatra, West Java, Borneo and the Philippines.

Uses

D. gracilis is an important source of keruing, especially in Indo-China. A wood-oil can be obtained from the bole and is used as a varnish and for illumination.

Observations

• A large tree of up to 50 m tall, bole branchless for 30 m or more, cylindrical, up to 180 cm in diameter, buttresses small to large, rounded, bark surface reddish-brown, older patches pink-brown or grey, outer bark grey-brown, inner bark reddish-brown, brittle, sapwood ochre; buds narrowly conical, scabrid rufous tomentose.
• Leaves elliptical to ovate, 8-15 cm × 4-10 cm, base obtuse, apex shortly acuminate, with 12-20 pairs of secondary veins, petiole 2-2.5 cm long, stipules narrowly lanceolate, outside persistently rufous tomentose.
• Stamens about 30.
• Fruit calyx tube spherical, glabrous, smooth, 2 larger fruit calyx lobes up to 14 cm × 2.5 cm, 3 shorter ones up to 2 cm × 1 cm.

D. gracilis is widespread, often occurring gregariously in seasonal semi-evergreen or evergreen dipterocarp forest on red soils, becoming scattered, rare, and confined to fertile red soils in the humid zones, up to 800 m altitude. The density of the wood is 580-1000 kg/m³at 15% moisture content. See also the table on wood properties. A natural hybrid between D. gracilis and D. costatus has been observed in Thailand and Peninsular Malaysia.

Selected sources

30, 31, 35, 102, 140, 175, 235, 253, 258, 264, 318, 461, 472, 476, 483, 497, 579, 628, 677, 737, 748.

Main genus page

• Dipterocarpus (Timbers)

Authors

• T. Smitinand (selection of species),
• C. Phengklai (selection of species),
• L.E. Groen (selection of species)