Shorea laevis Ridl. (Balau, bangkirai)
Nomenclature etc. DIPTEROCARPACEAE. Syn.: Shorea laevifolia (Parijs) Endert, Hopea laevifolia Parijs. Trade and local names: bangkirai, balau, selangan batu No.1 (trade, MAL, RI).
Tree. Geographic distribution: India, Pakistan, Sri Lanka, Burma, Thailand, Laos, Vietnam, Cambodia, and Indomalesia.
General. Heartwood basically brown to yellow to white or grey brown to green. Sapwood colour distinct from heartwood colour. Basic specific gravity 0.72–0.85–0.93 g/cm³.
Vessels. Wood diffuse-porous. Vessels in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 95–160–225 µm. Average number of vessels/mm² 3–6. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4–6 µm, vestured. Vessel-ray pits with distinct borders and with reduced borders or apparently simple, similar to intervessel pits, rounded or angular. Tyloses in vessels present (abundant), 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 parenchyma bands marginal (or seemingly marginal), fine, up to three cells wide and coarse, more than three cells wide. Parenchyma bands include axial resin canals. Axial parenchyma rarely apotracheal, or paratracheal. Apotracheal axial parenchyma diffuse-in-aggregates. Paratracheal axial parenchyma vasicentric, aliform, confluent, and unilateral paratracheal. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (2–)4–5.
Rays. Rays 5–8 per tangential mm, multiseriate, also if only few, 3–4 cells wide. Rays composed of a single cell type, or two or more cell types. Homocellular ray cells procumbent. Heterocellular rays square and upright cells restricted to marginal rows. Number of marginal rows of upright or square cells 1.
Storied structures. Storied structure present (not in all specimens), all rays storied, axial parenchyma storied.
Secretory structures. Intercellular canals present, axial type, in long tangential lines and in short tangential lines.
Mineral inclusions. Crystals not observed. Prismatic crystals, though observed very sporadically in axial parenchyma, may not considered a characteristic feature of this species. Silica not observed.
Physical and chemical tests. Water extract basically yellow or shade of yellow. Heartwood extractives leaching out when in contact with water (yellow). Splinter burns to charcoal.
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).