An Appreciation of Black Walnut
At one time, long ago, there were extensive, highly impressive forested areas of magnificent black walnut. Besides being important for its highly nutritious nuts, early European craftsmen cherished black walnut above all other woods. Because of this, many trees were felled. As a result, over time, most of the wild black walnut trees have all but disappeared from the North America landscape. During the war years and the depression, farmers, for need of money, would cut down their walnut trees as a source of income. Over a long period, there were even so-called “walnut rustlers” – thieves that used many illegal ways to cut down and steal walnut trees, sometimes involving chainsaws, midnight cutting raids and even helicopters to take away the stolen trees quickly. The trend continues even today. The wood is just that valuable.
Early loggers would dig around the roots of well-established trees, rather than cutting the tree down. This would expose the roots, which were then severed until the tree fell over. The shape of this wood where roots meet stump at ground level, had a natural curve to the grain which made for strong, and highly attractive gunstocks. Today, this market is limited. Now gunstocks can come from any part of the tree, particularly where fine figure is found.
Lots of Contrast
Highly prized black walnut heartwood is a rich brown, while it’s often discarded sapwood is a pale, creamy white. Though there is rarely a great reason to cut the sapwood off as scrap, it’s today’s trend.
Hardwoods can be divided into two broad groups – alternate and opposite – depending on how their leaves are arranged on the branch. Though a quick look can be deceiving, the leaves on a black walnut tree are spaced alternately, meaning there is space between where each leaf’s stem attaches to the branch. (Photo by Louis Landry)
Black Walnut Nut
About 2" in diameter, walnut nuts usually hang in clusters of one to three. They mature and drop in autumn. (Photo by Louis Landry)
Curly (left), crotch (center) and burl (right) are all common, and gorgeous, figures that can be found in walnut. (Photo by A&M Woods)
The grain of black walnut board is usually fairly straight. Small pores are visible on its surface.
With its even grain, and medium density, black walnut is a nice wood to work with hand tools.
In open areas, the black walnut is a beautiful, stately tree, often with large branches that fork low down on the trunk, and a rounded crown of strong ascending and spreading branches. The crown covers most of the tree’s height, but is open. In the forest, trees have a long, clear trunk and smaller crown. Leaves are compound, about 1′ long, with 15 to 23 leaflets. The familiar nuts need no description here. Even the bark on the black walnut tree is highly attractive. On young trees it is light brown, and on mature trees, dark brown to almost black, with rounded intersecting ridges. The trees grow to about 90 ft. tall, with a crown spread up to 80 ft. Cultivated trees may only reach 50′ or so in height. The trunk diameter is usually about 2-3′. Trees have a deep tap root, as well as deeply set lateral roots. Black walnuts prefer a deep, rich, well-drained loam soil. Once plentiful in southern Ontario, Quebec and areas of eastern USA, wild trees are now rare in Canada.
Squirrels play an important role in the natural reproduction of black walnut by gathering the nuts and hiding them in the soil. The germination of some of these buried walnuts is the principle means of distributing the species throughout the forest. Of course, for those wishing to start their own walnut grove, the squirrels would pose a problem, but wire fencing and other control means can easily be put in place.
Black walnut is highly prized for its rich coloured heartwood. The heartwood can range from a light pale brown to a dark chocolate brown with darker streaks, and can sometimes include purplish to reddish hues. The sapwood is pale yellow to nearly creamy white.
To steam or not to steam?
There are many woodworkers who do not consider the sapwood as being very valuable, and this is why most black walnut in the US is steamed. Steaming is done in a steamer (like a giant pressure cooker) shortly after the logs have been cut, and the boards are left there for a few hours. This darkens the sapwood by forcing some of the dark heartwood pigments into the sapwood. The result is a more uniform colour of lumber. However, some woodworkers would say that this steaming basically homogenizes the colour of the lumber. They feel that the natural, somewhat rainbow-like effect, of beautiful browns, golds and creams is lost. It is rather ironic that the dark colour of walnut wood is often favoured for contrasting with lighter coloured species of wood, in certain projects. It’s interesting that Canadian-produced black walnut lumber is not steamed.
Grain, figure, texture
Black walnut wood has a greater variety of often exquisitely beautiful figure types than any other wood. This is often a highly desirable feature. Figure grain in lumber refers to the appearance of the wood, and can be strikingly beautiful. Crotch figure from black walnut is cut from a part of the tree where the trunk divides into smaller limbs and branches and can be swirly in appearance. Burl figure is cut from a large growth on the side of the trunk or branch where grain swirls around. Curl figure refers to waviness or swirl in the wood grain and can be found in several parts of a fine specimen tree.
More generally, the grain of black walnut lumber is usually straight, fine and open, but can be irregular and more occasionally wavy or curly. The texture of the wood is rated as medium with a moderate natural lustre that grows more lustrous with age.
Black walnut wood is rated as very durable in decay resistance. It should be noted that black walnut trees can be tapped, just like sugar maple, for a tasty syrup.
Although the lumber is highly prized, today, because of high costs and lessened availability of highest quality timber specimen, walnut is mainly available as veneer. Even so, there is a tremendous demand for walnut veneer for woodworking items like furniture, cabinetry, interior finishing and much more. Black walnut veneer is often used to cover less expensive woods in many woodworking projects. Because of cost, the veneer available today is usually much thinner than many years ago. The best logs are often turned into veneer, though a good veneer log is quite rare.
If your woodworking project calls for strength and durability, then black walnut will meet your needs. It is easily worked with either hand or machine tools, particularly when the grain is straight and regular, and this includes turning and carving projects. The wood has good dimensional stability and shock resistance. It holds paint and stains very well (though walnut is rarely stained), providing an exceptional finish that is readily polished. It nails, screws and glues well. It also has good steam bending characteristics and moderate bending and crushing strength with low stiffness. Black walnut is quite a good wood for carving, as it tends not to chip and isn’t overly dense.
Price and Availability
Black walnut is one of the most valuable domestic hardwood species and is of prime importance as a timber tree. In Canada the supply is almost exhausted, so most of our black walnut lumber comes from the US. Select US black walnut wood is expensive; generally it is the highest priced domestic hardwood in North America.
Due to overharvesting the availability of high quality black walnut has diminished. Reforestation is a necessary part of any plan to harvest and use the wood. If you have the means, you could consider establishing your own walnut grove, but consider the following first.
Black walnut currently accounts for less than 1 percent of the hardwood production in the US. It represents about 2 percent of the total US hardwoods commercially available, and of course much, much less in Canada. It is estimated that most walnut logs only yield 20 percent select boards, as knots are quite common in sawn boards.
As well as few top-grade boards per tree and the small demand for Canadian walnut lumber, there is the cost of getting the trees to market. Cuts into your potential profits may include items such as hiring a logging truck, a two-man crew and possibly a skidder. Perhaps large acreages of walnut trees for lumber are best.
Back to the positive – a large diameter tree (about 18″ or more at breast height) with a tall, straight trunk can be worth tens of thousands of dollars. The price per log triples from saw log to veneer quality log. Going back to 1978, a veneer company paid $39,000 for a single black walnut tree. The demand continues, but perhaps not quite at this high a price. In a 1982 report, trees of standard harvest size had sold for as much as $12,000. Then think of the value of an old, huge walnut tree growing in an open area with low branches for figure and much more.
Because of the demand for and value of black walnut wood, considerable interest exists in improving the lumber production through research and developing new cultivars. Black walnut is truly a tree of great value for many woodworking projects.
Jesse is an author and instructor in environment, ecology, sustainability, horticulture and natural history. Check out his first book, “Quiver Trees, Phantom Orchids and Rock Splitters: Remarkable Survival Strategies of Plants”, at www.ecwpress.com/products/quiver-trees