Brazilian black rosewood wood structure

The wood material is characterized by its loose grain structure. The heartwood exhibits significant color variations, ranging from brown to reddish-brown hues, sometimes even reaching a deep purple-black tone, which clearly contrasts with the nearly white sapwood. This wood is known for its oily texture, giving it a distinctive appearance. Growth rings are not particularly noticeable, but when examined closely using a magnifying glass, the presence of numerous tube holes becomes apparent. These tubes are scattered throughout the wood, mostly small in size with some being slightly larger, and often show signs of sediment accumulation. Under magnification, axial thin-walled tissues can be observed, appearing in ring-like shapes or ribbon-like forms. The wood rays, also visible under a magnifying glass, are somewhat dense and very narrow. The growth patterns exhibit slight wave-like markings, while the intercellular canals remain unseen. For further details on this timber species, refer to Brazilian black rosewood.

Microscopic Features

The cross-section of the vessels shows an oval shape that is slightly polygonal. These vessels are solitary, with single or a few diameters per tube (2~5, rarely up to 9, typically around 2~3) and are scattered across the wood. On average, there are about 4 tubes per square millimeter, with the largest chord diameter reaching 261μm and an average of 149μm. The average length of the vessel elements is 236μm; some vessels contain gum and sediment, but no spiral thickening was observed. Intervessel pits are of the diffuse porous type, polygonal in shape, with grainy mouths. Some pits show slight deviations or confluent patterns, appearing lenticular or linear. Perforation plates are singular, positioned parallel to or slightly inclined. The arrangement of vessels and rays resembles the vessel-to-vessel configuration.

Axial parenchyma tissues are scattered and polymerized, forming bands (1~3 cells wide), rounded structures, loops, and wings. They include cells with prismatic crystals, which can contain up to six or more diamonds; spindle-shaped thin-walled cells are visible and arranged in stacks. The wood fibers have very thick walls, with a diameter of 20μm and an average length of 1295μm. The single pores are slightly narrow, and some fibers contain gum. Wood rays consist of 5~10 rays per millimeter, stacked together. Single rows of rays range from 2 to 10 cells high, while multi-row rays are 2 (or occasionally 3) cells wide and 5-10 cells high. The ray tissue includes both single columnar and multi-columnar types or profiled type III. Ray cells are either erect (rarely) or square, taller than horizontal ray cells; a few cells contain gum, but no crystals were observed. The intercellular canals are absent.