Dipterocarpus acutangulus (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Dipterocarpus acutangulus Vesque

Protologue: Compt. Rend. Hebd. Séances Acad. Sc. 78: 626 (1874).

Synonyms

• Dipterocarpus tawaensis v. Slooten (1927),
• Dipterocarpus helicopteryx v. Slooten (1940),
• Dipterocarpus appendiculatus auct. non R. Scheffer.

Vernacular names

• Brunei: keruing beludu
• Indonesia: mandurian putih, resak lebar daun, sagelam (East Kalimantan)
• Malaysia: keruing beludu (Sarawak, Sabah), keruing butik (Sarawak), keruing merkah (Sabah).

Distribution

Peninsular Malaysia and Borneo.

Uses

The timber is used as keruing.

Observations

• A large to very large tree of up to 60 m tall, bole cylindrical, branchless to a considerable height and with a diameter of up to 130 cm, buttresses few, short, rounded, bark surface reddish-brown to grey, inner bark reddish-brown, sapwood light ochre; buds ovoid, densely buff pubescent.
• Leaves elliptical to ovate, or rhomboid, 7-10 cm × 3-6 cm, base obtuse or cuneate, apex with long acumen, secondary veins 7-12(-14) pairs, petiole and leaf beneath caducous densely pubescent, petiole 15-25 cm long, stipules linear, obtuse.
• Fruit calyx tube globose or ellipsoid, with 5 ribs, surface warty, pruinose, 2 larger fruit calyx lobes about 10 cm × 2.5 cm, 3 shorter ones about 5 mm × 5 mm.

D. acutangulus occurs in mixed dipterocarp forest, on sandy soils, on coastal hills and inland ridges up to 1000 m altitude. It is a polymorphic species; some collections have leaf characters intermediate between D. acutangulus and D. globosus. The density of the wood is 690-880 kg/m³at 15% moisture content.

Selected sources

30, 89, 100, 258, 476, 677, 737, 746, 748.

Main genus page

• Dipterocarpus (Timbers)

Authors

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