Urban Walnut Trees: Are They Valuable?
by Don Janssen, Extension Educator
Reports of black walnut trees being sold for hundreds or even thousands of dollars often cause homeowners to dream of huge profits from selling their backyard walnut trees. Unfortunately, while good quality walnut trees are often quite valuable, walnut trees grown in an urban setting usually are not. Only an exceptionally large, high quality, urban grown walnut or group of walnut trees would interest a timber or veneer buyer.
Black walnut (Juglans nigra) has long been used for fine furniture, gun stocks, bowls and novelties because of its beautiful grain, color and the ease with which it can be worked. Good quality walnut logs are cut into lumber; the best are sliced into veneer.
Several key characteristics determine the value of a black walnut tree for timber or veneer-including trunk diameter, merchantable height and how free the trunk is from defects. While walnut buyers will occasionally purchase small trees, particularly if they are part of a group of trees being sold, trees less than 15 inches in diameter are of comparatively little value. Quality lumber and veneer trees generally have diameters of 18 inches or more.
A tree's diameter is measured 4 1/2 feet above the ground. It can be determined by measuring the circumference with a tape or string and dividing the circumference by 3.14.
The length of tree trunk that can be used for lumber or veneer is called its merchantable height. In black walnut and other hardwoods, merchantable height is usually the trunk height to major branches or forking. Minimum merchantable height for lumber and veneer black walnut trees is 8 to 10 feet. Quality lumber and veneer trees will have merchantable heights several times this height.
The quality of a hardwood tree is measured by how free its trunk is from defects such as crookedness, limbs, scars, swellings, bumps, cracks, holes, insect or disease damage, and wounds. Other factors being equal, the fewer the defects, the more valuable the tree.
Unfortunately, most urban walnut trees do not display the characteristics of high quality marketable trees. Urban walnuts often grow in open areas without surrounding trees. This results in trees with short trunks and numerous branches-little or no merchantable height. They are also more likely to have been struck by lightning or injured by human activities than trees grown in the woods. Even urban walnut trees that appear suitable as lumber or veneer trees usually are avoided by buyers because of the risk that they contain objects such as nails, wire, insulators, clothes line hooks, etc., which would damage saw blades or veneer knives.
The combination of poor quality, high risk of embedded objects and potentially difficult logging results in most urban walnut trees being of little interest to timber or veneer buyers. This does not mean that buyers would not be interested in an urban walnut that had a 30-inch diameter trunk, 32 feet of merchantable height in a straight trunk that was virtually free from visible defects, located in the middle of a large backyard away from any utilities or buildings. Unfortunately, there are very few such trees.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office