Commercial Timbers


H. G. Richter and M. J. Dallwitz

Bertholletia excelsa Humb. & Bonpl. (Castanheira)

Nomenclature etc. LECYTHIDACEAE. Trade and local names: castanha verdadeira, castanheira, c. do Pará (BR); castaña del Marañon, olla de mico (CO); Brazil nut (GB); Paranuss (DE). Not protected under CITES regulations ((locally (Brazil) on the IBAMA list of endangered plants)).

Tree. Geographic distribution: tropical South America (Brasil: Acre, Amazonas, Maranhão, Pará , Rondônia).

General. Growth ring boundaries distinct or indistinct or absent. Heartwood basically pinkish to light brown, without streaks. Sapwood colour distinct from heartwood colour. Odour indistinct or absent. Density 0.55–0.7 g/cm³. Wood of commercial potential (restricted since the trees are grown mainly for production of nuts, therefore felling is strictly regulated).

Vessels. Wood diffuse-porous. Vessels arranged in no specific pattern, in multiples, commonly short (2–3 vessels) radial rows. Average tangential vessel diameter 120–220(–300) µm. Average number of vessels/mm² 1–4. Average vessel element length 360–620–1000 µm. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 9–12 µm, not vestured. Vessel-ray pits with distinct borders, similar to intervessel pits, of uniform size or type. Helical thickenings absent. Tyloses in vessels present, thinwalled.

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness. Average fibre length 1100–1740–2360 µm. Fibre pits mainly restricted to radial walls, simple to minutely bordered. Helical thickenings absent. Fibres non-septate.

Axial parenchyma. Axial parenchyma banded. Axial parenchyma bands not marginal (or seemingly marginal), reticulate, fine, up to three cells wide. Axial parenchyma as strands. Average number of cells per axial parenchyma strand (4–)7–8.

Rays. Rays 5–10 per tangential mm, multiseriate (also if only few), 2–4 cells wide. Rays with multiseriate portions as wide as uniseriate portions absent. Aggregate rays absent. Rays of one size. Rays composed of a single cell type (homocellular), or two or more cell types (heterocellular); homocellular ray cells procumbent. 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 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 absent. Laticifers or tanniniferous tubes absent.

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

Mineral inclusions. Crystals present, prismatic, located in axial parenchyma cells. Crystal-containing axial parenchyma cells chambered. Number of crystals per cell or chamber one. Cystoliths absent. Relatively small crystals in long chambered strands always located at the adaxial side of parenchyma bands. Silica not observed.

Illustrations. • Transverse section. Bertholletia excelsa. • Tangential section. Bertholletia excelsa. • Radial section. Bertholletia excelsa. • Miscellaneous. Bertholletia excelsa. Crystals in long chains, cell walls unilaterally thickened.

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.’.