Wisdom Behind The Wood #2: Black Walnut

Welcome back everyone to my second installment of Wisdom Behind The Wood! For those who are new, my name is Nolan Russell, Operations Manager here at The Boardsmith. This segment dives deeper into the trees, lumber, and the science that make our butcher block the best in the world. I am a Certified Arborist, former Tree Care Professional, and all-around tree nerd.


This month we’re covering all about black walnut wood, one of my favorites! The Carolina Cut End Grain Walnut cutting board is our third most popular cutting board (behind Carolina Cut End Grain Maple and Butcher End Grain Maple). The scientific name for black walnut/Eastern black walnut/American walnut is Juglans nigra. A truly prized tree, the black walnut uses by Native Americans included medicinal purposes and for dye for hundreds of years. Common modern black walnut uses include gathering nuts for food, grinding the shells for use in many industrial processes, and harvesting the wood for furniture and veneer. The black walnut tree has a wide native range that stretches from Kansas to the East Coast. Its Northern limit is New York, and it seldom grows further South than the panhandle of Florida. Unlike hard maple, black walnut is seldom grown as timber wood in monoculture stands. This is because black walnut naturally occurs as a secondary species in forests dominated by: hard maple; yellow-poplar; yellow-poplar, white oak, and northern red oak; beech and hard maple; silver maple and American elm.


From a woodworker's perspective, black walnut can be a difficult wood to work with. Black walnut tends to be disease-prone, and its mostly wild growth leads to a higher presence of knots, checks, and voids. Another black walnut characteristic is that it tends to have high levels of contrast between the darker chocolate brown heartwood of the tree and the lighter off-white of the sapwood. Almost all the commercially produced walnut is “steamed” during kiln drying. The process basically introduces high humidity into the kiln and allows the extractives that give walnut its brown color to move around in the wood. This evens out the wood to the black walnut characteristic brown color and allows some of the sapwood to be reclaimed. Un-steamed black walnut tends to have deeper reds, purples, and browns with whiter sapwood.


Due to the heavy demand and aggressive harvesting of black walnut for furniture, veneers, and cabinetry, supply of high quality walnut has declined. So much so, walnut lumber receives its very own grading system, and is generally graded to a lower standard than other common hardwoods. At the Boardsmith, our partnership with a family-owned sawmill in Pennsylvania allows us to overcome some of these challenges and receive superlative walnut lumber. We think this is reflected in our product and makes our walnut cutting boards stand out.


Black walnut is more expensive than most other woods, but the results are worth it. The beautiful dark chocolate luster of the wood presents nicely. Black walnut exists in a good space between hard maple (1450 Janka scale) and black cherry (950 Janka scale) at 1010 on the Janka scale. This makes it slightly more durable than cherry but softer on expensive knives than hard maple. Black walnut tends to be slightly more dimensionally stable than hard maple and less sensitive to seasonal moisture changes.


Thank you for taking the time to read about black walnut wood! Next month come back and we'll learn a little bit about our most underrated wood species: the black cherry tree aka Prunus serotina.