Black Walnut

Description

Overall view of a Black walut tree in a grassy area.

Black Walnut (Juglans nigra /Juglandaceae). Black Walnut is native to the eastern United States, from southern Minnesota east to Pennsylvania, New Jersey, New York; south to South Carolina, Georgia, Florida, Alabama; west to Texas; and north through Oklahoma, Kansas, Nebraska, and South Dakota. Black Walnut trees reach heights of 120 ft (37 m), with a diameter of over 3 ft (1 m). Juglans nigra sapwood is light tan, with the heartwood being a dark, chocolate brown, sometimes having a purplish cast. Juglans nigra is hard, heavy, hard and stiff (high shock resistance). The wood has a straight grain, is easily worked, finishes well and holds paint and stain. It is a most durable wood, even under conditions favorable to decay (moist conditions). It is used for cabinets, fixtures, furniture, gunstocks, interior paneling, novelties and veneer.

Tech Sheet

https://research.fs.usda.gov/silvics/black-walnut

Characteristics

Close view of Black walnut leaves and fruit on a branch.

Characteristics found in the American Black Walnut (Juglans nigra):

  • Semi-Ring Porous
  • Reticulate parenchyma
  • Tyloses & deposits
  • Simple perforations
  • I/V pits large (13 - 50µ)
  • Rays 1-8 seriate & homocellular to heterocellular
  • Ray cells round as viewed on the tangential surface
  • Crystals in Axial Parenchyma (chains of 1-5)
  • “Gashes” in Latewood Vessels

Slides (Click on each image to view a larger image)

WOOD SLIDES

Microscope slide of transverse section of black walnut wood. Arrows point to earlywood growth ring boundary and lightwood.

Cross-section of American Black Walnut (Juglans nigra) showing growth ring boundary and reticulate parenchyma in the latewood.

Microscope slide of tangential section of black walnut wood. Arrows point to crystals.

Radial section of American Black Walnut (Juglans nigra) showing a chain of crystals.

Microscope slide of radial section of black walnut wood. Arrows point to gashes in the vessels and rays.

Radial section of American Black Walnut (Juglans nigra) showing “gashes” in a latewood vessel.

Microscope slide of radial section of black walnut wood at higher magnification. Arrows point to gashes in the vessels and the rays.

Radial section of American Black Walnut (Juglans nigra) showing a close-up of “gashes” in a latewood vessel.

Microscope slide identical section of black walnut wood. Arrows point to enter vessel pits, perforation plate and rays.

Radial section of American Black Walnut (Juglans nigra) showing inter-vessel pits.

Microscope slide of tangential section of black walnut wood. Arrows point to the rays and axial parenchyma.

Tangential section of American Black Walnut (Juglans nigra) showing circular ray cells.

Microscope slide of tangential section of black walnut wood. Arrows point to crystals.
Microscope slide of tangential section of black walnut wood. Arrows point to axial parenchyma and crystals.
Microscope slide of tendential section of black walnut wood. Arrows point to raise and tylosis.

CHARCOAL SLIDES

Microscope slide of radial section of black walnut charcoal. Arrows point to the rays and the vessels.
Microscope slide of tangential section of black walnut charcoal. Arrows point to the vessels.
Microscope slide of tangential section of black walnut charcoal at higher magnification. Arrows point to the vessels.
Microscope slide of tangential section of black walnut charcoal at higher magnification. Arrows point to the race.
Microscope slide of transverse section of walnut charcoal. Arrows point to the rays, vessels and growth ring boundary.
Microscope slide of transverse section of black walnut charcoal at higher magnification. Arrows point to the rays in the growth ring boundaries
Microscope slide of transverse section of black walnut charcoal at high magnification. Arrows point to the vessels growth ring boundary and raise.
Microscope slide of transverse section of black walnut. Arrows point to the vessels raised and growth ring boundaries.
Microscope slide of transverse section of black walnut charcoal. Arrows point to the rays, vessels and the growth ring boundary.