Commercial Timbers


H. G. Richter and M. J. Dallwitz

Hopea spp. (Merawan)

Nomenclature etc. DIPTEROCARPACEAE. Hopea acuminata, H. beccariana, H. dryobalanoides, H. mengarawan, H. nervosa, H. odorata, H. sangal, etc. Trade and local names: merawan (MY, trade); luis, damar kemantok (BN); damar mata kucing (ID-sum); gagil (MY, ID-kal); light hopea (PG, GB); manggachapui (PH); koki (KH); khen (LA); thingan (MM); takhian-thong (TH); sao den (VN). Not protected under CITES regulations.

Tree. Geographic distribution: Burma to Indomalesia.

General. Heartwood basically brown to yellow, without streaks. Sapwood colour distinct from heartwood colour. Density 0.4–0.75 g/cm³.

Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 140–200 µm. Average number of vessels/mm² 13–40. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5–7 µm, vestured. Vessel-ray pits with reduced borders or apparently simple, rounded or angular (circular to oval). Helical thickenings absent. Tyloses in vessels present, thinwalled.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled, or of medium wall thickness. Average fibre length 1200–2200 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Fibres non-septate.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma bands not marginal (or seemingly marginal). Banded parenchyma only connecting axial intercellular canals. Axial parenchyma apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma scanty, or vasicentric, or aliform, or confluent. Aliform parenchyma winged. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–6.

Rays. Rays 5–11 per tangential mm, multiseriate (also if only few), (1–)2–7 cells wide. Height of large rays commonly 500 to 1000 µm, or commonly over 1000 µm. Rays composed of two or more cell types (heterocellular). Heterocellular rays with square and upright cells restricted to marginal rows, mostly 1 marginal row of upright or square cells or mostly 2–4 marginal rows of upright or square cells. Sheath cells present (present in some species, absent in others), or absent.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals present, non-traumatic origin, axial type, in long tangential lines or in short tangential lines.

Cambial variants. Included phloem absent.

Mineral inclusions. Crystals present, prismatic or druses (druses observed only in H. ferruginea), located in ray cells or axial parenchyma cells. Crystal-containing ray cells upright and/or square or procumbent, upright and/or square ray cells chambered or not chambered. Crystals in procumbent ray cells in radial alignment. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Silica not observed.

Illustrations. • Transverse section. Hopea mengarawan. • Tangential section 1. Hopea mengarawan. • Tangential section 2. Hopea odorata. Note different ray composition in Hopea odorata as opposed to H. mengarawan. • Radial section. Hopea mengarawan.

The interactive key allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting specified attributes, summaries of attributes within groups of taxa, and geographical distribution.

Cite this publication as: ‘Richter, H.G., and Dallwitz, M.J. 2000 onwards. Commercial timbers: descriptions, illustrations, identification, and information retrieval. In English, French, German, Portuguese, and Spanish. Version: 25th June 2009.’.