What Do Walnut Trees Provide for People?

Lumber

• Walnut wood is sought after for items such as furniture and cabinetry. More mature trees tend to bring more money, especially if they are free of defects such as knots and holes. Black walnut in particular is coveted for its strength and attractive grain, although English walnut wood also is durable and used in woodworking. A black walnut tree must be at least 18 inches in diameter to gain the most money as a veneer-quality tree. Lumber-quality trees, or trees with minor defects that don't allow them to be cut into veneer slices, are often harvested when they are 16 inches in diameter. Larger trees in both walnut varieties tend to bring in more money per board foot, but you risk defects forming in high-quality trees if you wait too long.

Walnuts

• Although it takes four or more years for most walnut trees to start bearing fruit, they typically provide an abundant supply in the early fall. Walnuts make tasty snacks and recipe additions, and they can keep in the freezer for up to two years. English walnut trees are well known for their nuts, and these are the ones most commonly seen in the United States. Black walnut trees also produce edible nuts, although they are harder to crack. These walnuts usually have a thick hull covering the shell, and both must be removed to access the nut meat. You can use hammers to crack the hulls, although some people go to extremes such as running a car over the nuts that are especially hard to crack open.

Hulls and Sap

• When you've removed the shells from English or black walnuts, don't toss them out; they have a variety of uses around the house. The shells burn similarly to wood, helping you to provide heat or helping you build a fire in your fire pit. After being crushed with a hammer, they work well as pet litter or to help provide traction over snow and ice. The shells can produce a dye suitable for changing the color of leather, cloth and wood -- or your fingers, so wear protective gloves if you are making a dye from the shells. English walnuts give you a buttery tan color, while black walnuts typically provide a deeper shade of brown. Walnut trees also offer a relatively untapped resource: their sap. It has a lower sugar content than maple, which means you must concentrate more sap to create a breakfast-ready syrup. According to Cornell University, the syrup's flavor is similar to maple syrup, although it's a bit nuttier with a hint of butterscotch.

Trouble

• All is not fun and games near your walnut trees -- they provide a bit of trouble for the avid gardener looking to decorate every corner of his yard. The trees release juglone into the soil, which makes it toxic to many nearby plants. Most walnut trees, including English walnut, add at least some juglone to the soil, but this is especially a problem with black walnut trees. The juglone is found in all parts of the tree, including the roots, wood, leaves and nuts. Other walnut trees might grow nearby, but you'll likely have a problem growing many types of ornamental plants and grass near black walnut trees. English walnut trees that aren't grafted onto black walnut rootstock add such a small amount of juglone to their area that most nearby plants aren't affected.