Commercial Timbers


H. G. Richter and M. J. Dallwitz

Pyrus communis L. (Birnbaum, pear)

Nomenclature etc. ROSACEAE. Including cultivars which are generically summarized under P. communis var. sativa. Trade and local names: Birnbaum, Schweizer Birnbaum (DE, CH, AT), pear (GB), poirier (FR), peren (NL), pera, perastro (IT), pereira (PT), peral (ES), körte (HU), grusza (PL). Not protected under CITES regulations.

Tree. Geographic distribution: Europe, excl. Mediterranean and Mediterranean incl. N. Africa and Middle East (cultivated worldwide in temperate climate zones).

General. Growth ring boundaries distinct. Heartwood basically brown to white or grey brown to red to white or grey. Sapwood colour similar to heartwood colour. Density 0.6–0.76 g/cm³. Formation of traumatic heartwood quite common, dark reddish brown with colour streaks.

Vessels. Vessels present. Wood diffuse-porous. Vessels exclusively solitary. Vessel outline angular. Average tangential vessel diameter 30–50 µm. Average number of vessels/mm² 100–150. Perforation plates simple. Intervessel pits alternate, average diameter (vertical) 4(–6) µm. Vessel-ray pits with distinct borders, similar to intervessel pits. Helical thickenings present (few), in narrow and wide vessel elements, throughout the body of vessel elements. Other deposits in heartwood vessels present (reddish brown).

Tracheids and fibres. Vascular or vasicentric tracheids sporadic to absent. Fibres of medium wall thickness. Fibre pits common in both radial and tangential walls, distinctly bordered.

Axial parenchyma. Axial parenchyma apotracheal and paratracheal. Apotracheal axial parenchyma diffuse and diffuse-in-aggregates. Paratracheal axial parenchyma scanty. Axial parenchyma as strands. Average number of cells per axial parenchyma strand 3–6.

Rays. Rays 10–16 per tangential mm, multiseriate (also if only few), (1–)2–4 cells wide. Rays composed of a single cell type (homocellular); homocellular ray cells procumbent.

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

Illustrations. • Macro images. Pyrus communis. Transverse. Tangential. • Transverse section. Pyrus communis. • Tangential section. Pyrus communis. • Radial section. Pyrus communis.

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.’.