Black walnut is one of the best trees to grow for timber. Each year about eighteen million board feet (A board foot is twelve inches by twelve inches by one inch) of black walnut lumber are harvested in Indiana. Black walnut is a valuable hardwood, and it grows faster than many other hardwoods. Keep in mind that it takes considerable resources to grow black walnut timber. For starters, you will need at least ten acres of land. Timber of harvesters will not be interested in anything smaller. It will also take a lot of time – A minimum of twenty-five years before harvesting. It will also require good forest management.
Locating Your Black Walnut Grove
Black walnut trees require good, deep, well-drained soil. They have a taproot that goes deep (Up to ten feet), and their lateral roots spread out wide (Up to eighty feet from the trunk). These roots produce a chemical called juglone, which is toxic to some other plants, such as tomatoes or apple trees. Therefore you will want to avoid planting too close to your garden or orchard. They do best with full sun, and should have a minimum of six hours sunshine each day. You will want to keep livestock away from your trees, and deer may eat seedlings when they are small. If there are deer in your area, you will want to put guards around the seedlings until they grow larger. Once they get some growth on them, deer won’t eat them, but they damage the young trees by rubbing their antlers against them.
Planting: Seedlings Versus Seeds
It won’t make much difference whether you plant a one year-old seedling or a seed. Walnuts have a deep taproot which will be damaged during transplanting. After a few years they will both be about the same size. If you are on a tight budget, it’s probably best to plant seeds. You can probably find them in the wild somewhere growing along a road.
Planting Black Walnut Seeds
It is best to collect black walnut seeds soon after they drop from the tree in the fall. Collect more than you intend to plant, since some may not be good. Once you have collected them, you’ll need to remove the green husks. The easiest way is to lay them on the ground and let the husks turn brown. At that point you can remove the husks with a hammer or driving your car over them. Drop the nuts into a bucket of water to see if they float. Discard any that do. The seeds should be planted one to two inches deep.
Planting Black Walnut Seedlings
Planting bare root seedlings is probably the easiest route. They can be purchased inexpensively from the Indiana Department of Natural Resources. The also have what they call their select line seedlings, which come from their best trees. Since they are only a few dollars more for a hundred saplings, it’s probably best to purchase these. There are also cultivars, which are clones of black walnut trees with desirable traits. For information on planting, please go to the Planting Your Acreage section of our Black Locust Firewood page.
Purdue University Black Walnut Improvement Program
In 1968 Purdue University began a program to identify and clone black walnut trees that grew fast and / or produced good nut crops. The program was led by Walter F. Beineke, a forest genetics professor. Trees were evaluated for growth rate, nut production, straightness, resistance to anthracnose and leafing date. A total of nine cultivars were patented. They are documented in Characteristics of Purdue University’s Patented Black Walnut Trees. The fastest grower was Tippecanoe 1, while Fayette 2 was the most prolific nut producer. The best all-around cultivar was Purdue 1, which had both fast growth and abundant nut production.
These genetically improved trees are available from Advanced Tree Technology, located in New Haven, Indiana. They sell grafted trees, which are genetically identical to the Purdue 1 and Tippecanoe 1 cultivars, as well as seedlings which came from the seeds produced by those cultivars. Unfortunately, they are quite expensive.
Walter Beineke is now retired after teaching for thirty-five years. During his career he obtained twenty-five tree patents: One for black cherry, one for white oak and twenty-three for black walnut. Some of his patents are listed Some of his (and many others) are listed on the Justia Patents website. Some of these are for varieties which produce better nuts as well as better timber. There are also patents for improved rootstocks which cultivars can be grated onto.
Managing Your Plantation
The recommended spacing of your trees for timber production is twelve feet apart. For nut production, they should be twenty-five feet apart, so the tree can spread out and get plenty of sunlight. The tighter spacing for timber production encourages the trees to grow straight upward.
It’s important to rid the area around your seedlings of weeds and grass, especially in their early years. This is best done with herbicides. Once the trees exceed six feet in height, you want to start trimming the side branches. Ideally, slightly less than the bottom half of the tree should be devoid of branches. This will increase the value of your timber. Any trees which are not growing well should be thinned out. Always go for quality over quantity.
When talking about size, foresters always refer to DBH, or diameter breast height (four and one-half feet above the ground). Your trees need to have a DBH of at least twenty inches to sell them. However, they need to be at least twenty-four inches for the veneer market. The veneer market requires high quality timber, and they pay significantly more per board foot. Just because your trees are large enough to sell, doesn’t mean you should sell them. As the tree grows larger, you have more board feet to sell. You will likely be able to get a better price per board foot for logs that are longer and larger diameter. Here’s a video that explains grading of logs. Remember – Quality over quantity! Grow the highest quality black walnut timber possible.