Shorea spp., subg. Rubroshorea (Red Balau)
Nomenclature etc. DIPTEROCARPACEAE. S. balangeran (Korth.) Burck, S. collina Ridl., S. guiso (Blco.) Bl., S. kunstleri King, S. Ochrophloia E.J.S. ex Sym.; S. guiso (Blco.) Bl. - Syn.: S. vulgaris Pierre ex Lanessan, S. longipetala Foxw., Dipterocarpus guiso Blanco, Anisoptera guiso A.DC. Trade and local names: red balau (D, MAL), gujio (RP), semayur (MAL.Sar.), belangeran (RI), selangan batu merah (MAL-Sab./Sar.).
Tree. Geographic distribution: Thailand, Laos, Vietnam, Cambodia and Indomalesia.
General. Heartwood basically brown to red (dark). Sapwood colour distinct from heartwood colour. Basic specific gravity 0.75–0.92 g/cm³.
Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 125–190–255 µm. Average number of vessels/mm² 2–4. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 6–10 µm, vestured and not vestured. Vessel-ray pits with distinct borders or with reduced borders or apparently simple, similar to intervessel pits, rounded or angular or horizontal to vertical, of the same type in adjacent elements or unilaterally compound and coarse. Tyloses in vessels present, thinwalled.
Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres very thick-walled. Fibre pits mainly restricted to radial walls, simple to minutely bordered.
Axial parenchyma. Axial parenchyma banded (axial resin canals embedded in parenchyma bands). Axial parenchyma bands not marginal (or seemingly marginal). Axial parenchyma rarely apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric, aliform, and unilateral paratracheal. Aliform parenchyma lozenge. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 4–6.
Rays. Rays 4–8 per tangential mm, multiseriate, also if only few, 2–4 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 rays square and upright cells restricted to marginal rows. Number of marginal rows of upright or square cells 1, or 2–4, or more than 4. Sheath cells absent.
Storied structures. Storied structure present, axial parenchyma storied.
Secretory structures. Intercellular canals present (resin canals), axial type, in long tangential lines and in short tangential lines.
Mineral inclusions. Crystals present, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered and not chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size and enlarged (idioblasts). Shorea guiso belongs to the subgenus Shorea but is traded as Red Balau because of its red colour; crystalliferous chambered parenchyma cells are abundant in this species as opposed to the others described herein. Silica not observed.
Miscellaneous. • Wood surface. Shorea pauciflora, radial plane.
Cite this publication as: H. G. Richter and M. J. Dallwitz (2000 onwards). 'Commercial timbers: descriptions, illustrations, identification, and information retrieval.' In English, French, German, and Spanish. Version: 4th May 2000. http://biodiversity.uno.edu/delta/.
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993 onwards, 1995 onwards, 1998) should also be cited (see General references).
