Commercial Timbers


H. G. Richter and M. J. Dallwitz

Robinia pseudoacacia L. (Robinie, black locust)

Nomenclature etc. FABACEAE-FABOIDEAE. Trade and local names: Robinie, Falsche Akazie, Akazie, Gemeiner Schotendorn (DE), robinier (FR), false acacia (GB), black locust, yellow locust (US), robinia (NL, IT), akat (CZ), bagrem, robinija (CS), salcam (RO), akacja biala (PL), fehér akác (HU). Not protected under CITES regulations.

Tree. Geographic distribution: Europe, excl. Mediterranean and North America.

General. Growth ring boundaries distinct. Heartwood basically brown to yellow to green. Sapwood colour distinct from heartwood colour. Density 0.54–0.74–0.87 g/cm³.

Vessels. Vessels present. Wood ring-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows and in clusters (both early and latewood). Vessel outline rounded. Average tangential vessel diameter 130–180–220 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 7–11 µm, vestured and not vestured. Vessel-ray pits with reduced borders or apparently simple, rounded or angular. Helical thickenings present, only in narrow vessel elements, throughout the body of vessel elements. Tyloses in vessels present (extremely so), thinwalled.

Tracheids and fibres. Vascular or vasicentric tracheids commonly present. Fibres of medium wall thickness. Average fibre length 760–1000–1250 µm. Fibre pits common in both radial and tangential walls, simple to minutely bordered.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma paratracheal. Paratracheal axial parenchyma scanty, vasicentric, and aliform. Aliform parenchyma lozenge. Axial parenchyma fusiform and as strands. Average number of cells per axial parenchyma strand 2–4.

Rays. Rays 6–8 per tangential mm, multiseriate (also if only few), (1–)2–6 cells wide. Rays of two distinct sizes. Height of large rays commonly 500 to 1000 µm, or commonly over 1000 µm. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent.

Storied structures. Storied structure present (macroscopically hardly visible), axial parenchyma storied, vessel elements storied.

Mineral inclusions. Crystals present, prismatic, located in ray cells and axial parenchyma cells. Crystal-containing ray cells procumbent. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Silica not observed.

Physical and chemical tests. Heartwood fluorescent (bright yellow).

Illustrations. • Trees. Solitary Black Locust tree at the Royal Botanic Gardens, Kew, England. Photograph by courtesy of Ms Edda John, head of the Wood Structure and Quality laboratory, BFH Hamburg, Germany. Robinia pseudoacacia. • Macro images. Robinia pseudoacacia. Transverse. Tangential. • Transverse section. Robinia pseudoacacia. • Tangential section. Robinia pseudoacacia. Note: Storied axial parenchyma cells (AP). AP. • Radial section. Robinia pseudoacacia. • Miscellaneous. Robinia pseudoacacia. Complete blockage of vessels by tyloses. Spiral thickenings in latewood vessels. • Crystals in rays and axial parenchyma. Robinia pseudoacacia. Prismatic crystals present in ray (left) and axial parenchyma (right) cells, generally infrequent.

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.’.