Commercial Timbers


H. G. Richter and M. J. Dallwitz

Toona spp. (kalantas, surian, toon)

Nomenclature etc. MELIACEAE. Incl. T. calantas Merr. & Rolfe, T. ciliata M.J. Roemer, T. cf. serrata, T. sureni (Blume) Merr. Trade and local names: suren (RI); red cedar (PNG); kalantas (RP); thitkado (BUR); chomcha (K); yom-hom (T). Not protected under CITES regulations.

Description based on 8 ((T. calantas (4), T. ciliata (2), T. cf. serrata (1), T. sureni (1)). Tree. Geographic distribution: Thailand, Laos, Vietnam, Cambodia and Indomalesia.

General. Growth ring boundaries distinct. Heartwood basically brown and red, without streaks. Odour distinct. Wood of commercial potential.

Vessels. Vessels present. Wood semi-ring-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows, radial rows of 4 or more, and in clusters. Vessel outline rounded. Two distinct vessel diameter classes absent. Average tangential vessel diameter 100–200–270 µm; diameter of vessel lumina: large and very large. Average number of vessels/mm² 2–4 (exception: T. sureni with 9–12 vessels per mm²); vessels per square millimetre very few. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 5 µm, small, not vestured. Vessel-ray pits with distinct borders, similar to intervessel pits, of uniform size or type, of the same type in adjacent elements, located throughout the ray. Helical thickenings absent. Tyloses in vessels absent. Other deposits in heartwood vessels present (reddish brown).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres very thin-walled and of medium wall thickness. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma present, banded. Axial parenchyma bands marginal (or seemingly marginal), bands much wider than rays, fine, up to three cells wide and coarse, more than three cells wide. Axial parenchyma paratracheal. Paratracheal axial parenchyma vasicentric. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–6–8. Unlignified parenchyma absent.

Rays. Rays present, (3–)4–8(–14) per tangential mm, multiseriate (also if only few), (1–)2–4 cells wide, narrow (2–3 seriate) and of medium width (3–5 seriate). Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Height of large rays up to 500 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. Sheath cells absent. Tile cells absent. Perforated ray cells absent. Disjunctive ray parenchyma end walls indistinct or absent.

Storied structures. Storied structure absent.

Secretory structures. Oil and mucilage cells absent. Intercellular canals present and absent, traumatic origin, axial type, in long tangential lines. Traumatic intercellular canals observed only in T. sureni.. Laticifers or tanniniferous tubes absent.

Cambial variants. Included phloem absent. Other cambial variants absent.

Mineral inclusions. Crystals present, prismatic and druses, located in ray cells and axial parenchyma cells. Crystal-containing ray cells upright and/or square and procumbent, upright and/or square ray cells not chambered. Crystal-containing axial parenchyma cells not chambered. Number of crystals per cell or chamber one. Crystal containing cells of normal size. Cystoliths absent. Druses in axial parenchyma; prismatic crystals in both rays and axial parenchyma.. Silica not observed.

Physical and chemical tests. Heartwood not fluorescent. Water extract not fluorescent; basically colourless to brown or shade of brown. Heartwood extractives not leachable by water. Ethanol extract fluorescent (weakly). Colour of ethanol extract colourless to brown or shade of brown. Chrome azurol-S test negative. Froth test negative (weakly positive). Splinter burns to partial ash. Ash white to grey.

Illustrations. • Macro images. Toona sp. Transverse. Radial. • Transverse section: T. serrata. Toona serrata. • Transverse section: T. ciliata. Toona ciliata. • Tangential section. Toona serrata. • Radial section: T. serrata. Toona serrata. • Radial section: T. ciliata. Toona ciliata. • Crystals in rays and axial parenchyma. Toona ciliata. DR. CRap. CRr. Druses (DR) and prismatic crystals in axial parenchyma (CRap) as well as in rays (CRr).

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.’.