Chestnut Lumber Identification

American and Chinese chestnut trees look very similar.

American chestnut wood, or Castanea dentata, is rare on the North American lumber market. This wood was once plentiful and used in a wide variety of woodworking projects. However, in the early part of the 20th century, this tree was heavily affected by chestnut blight. Only a few American chestnut trees remain. All chestnut lumber currently available is imported or scavenged from old buildings. Chestnut wood in old buildings or furniture can look a lot like oak, but has some key features.

Ring Porousness

Chestnut is a ring porouswood as are both red and white oak. These woods have bands of large wood cells running parallel to their bark, producing a spotted appearance. The large cells are darker than the smaller ones surrounding them. Other common hardwoods, such as maple, poplar an d willow, are diffuse porous and show more consistent coloration.

Color

American chestnut trees produce white to light brown sapwood, which is relatively narrow in comparison to the heartwood. They produce gray-brown to brown heartwood. This part of the tree darkens as it ages, and older specimens may be dark brown to walnut in tone. Wood that remains in contact with iron under damp conditions may develop blue-black stains. It can be difficult to distinguish chestnut wood from other lumber based on color alone, since this wood can vary so much from one tree to the next.

Rays

Chestnut wood produces a distinct ray pattern that helps distinguish it from oak and other related trees. According to the University of Tennessee, rays are groups of cells extending from the pith of the tree to its bark. In oak, these rays are very wide and readily visible to the naked eye. In chestnut, the rays are quite narrow. They can be hard to see without a magnifying glass or microscope.

"Wormy" Chestnut

Wormy chestnut was originally considered a defective grade of lumber but is now sometimes prized for its interesting appearance. Chestnut trees are much more subject to attack by wood-eating insect larvae than are other species and usually have at least a few holes in the heartwood. Heavily-holed wood, often taken from trees already killed by chestnut blight, may be called "wormy." It is commonly taken from barns and other old structures for use in rustic furniture and cabinetry. Wormy chestnut is not as strong as chestnut without holes.

References

• Woodworkers Source: Castanea dentata
• The University of Tennessee; Identifying Chestnut Wood; Adam M. Taylor