The bulk of the xylem is made up of thick-walled libriform fibres. Their proportion is 58% with an average length of 1 mm.
The wide earlywood vessels (150-220 mikro-m) are arranged in a 2-3 vessels thick ring. They are heavily clogged by tyloses in the heartwood. Latewood vessels have smaller diameters (70-140 mikro-m) and are either single or trimmed in small tangential and radial groups. The ratio of vessels in the tissue is about 15%.
Rays amount to approx. 21%, and they are narrow (1-3 cells).
The longitudinal parenchyma is paratracheally arranged along the vessels and often assembled in longitudinal rows. Their share is only 6% section.
The longitudinal and the ray parenchyma often contain crystalline deposits.
Because of various clogging substances and tylosis, black locust is impermeable to liquids in all directions. Quarter-sawing is not a requirement for black locust staves.