Species guide

American walnut

Latin name

Juglans nigra

Other Common names

Black walnut, American walnut

Distribution

Throughout eastern USA, but principal commercial region is the Central States. One of the few American species planted as well as naturally regenerated.

General Description

The sapwood of walnut is creamy white, while the heartwood is light brown to dark chocolate brown, occasionally with a purplish cast and darker streaks. Walnut can be supplied steamed, to darken sapwood or left unsteamed. The wood is generally straight grained, but sometimes with wavy or curly grain that produces an attractive and decorative figure.

Working Properties

Walnut works easily with hand and machine tools, and nails, screws and glues well. It holds paint and stain very well and can be polished to an exceptional finish. It dries slowly, and care is needed to avoid kilning degrade. Walnut has good dimensional stability.

Physical Properties

Walnut is a tough hard timber of medium density, with moderate bending and crushing strengths and low stiffness. It has a good steam bending classification.

Durability

Rated as very resistant to heartwood decay, it is one of the most durable woods even under conditions favourable to decay. Sapwood liable to attack by powder post beetles.

Availability

USA:
Reasonable availability with regional limitations.

Export:
Reasonable availability in both lumber and veneer.

Main Uses

Furniture, cabinet making, architectural interiors, high class joinery, doors, flooring, and panelling. A favoured wood for using in contrast with lighter coloured timbers.

Grading

The grades have been tweaked to allow shorter clear cutting areas because of the nature of walnut’s growth. The FAS grade allows a 5 inch (12.7cm) minimum width and a 6 ft (1.83m) minimum length. Small burls and swirls in the grain are natural characteristics and are not considered a defect. The lumber, when fresh sawn, is steamed to darken the sapwood for ease of blending into the heartwood when finishing. There is no minimum standard for this process so care should be taken when ordering and communicate with the supplier.

Technical statistics

Specific Gravity (12% M.C.):	0.55
Average Weight (12% M.C.):	609 kg/m3
Average Volume Shrinkage (Green to 6% M.C.):	10.20%
Modulus of Elasticity:	11,584 MPa
Hardness:	4492 N