Black walnut trees are widely known for their valuable timber, but researchers at the University of Missouri are working to put the spotlight on another opportunity: the nuts. In doing so, the diversification could help generate more economic opportunity for farmers, ranchers and landowners, especially in areas where it’s difficult to grow crops.
At the university’s Horticulture and Agroforestry Research Farm, about 30 miles from the Columbia campus, a collection of black walnut trees is helping researchers identify traits that could make nut production a more attractive option for farmers and landowners.
Some of the trees in the orchard are now 30 years old, planted in 1996 as part of the university’s first black walnut repository.
“These are like chance seedling collections that occurred usually in on-farm environments that were collected over the 20th century by grower association members for the reason of high kernel percentage and high kernel mass,” says Ronald Revord, an associate professor in the University of Missouri’s School of Natural Resources and director of the Center for Agroforestry.
Wild eastern black walnuts typically have kernel percentages ranging from about 6% to 14%. The trees in this collection can reach 20% to the mid-30% range, Revord says, meaning a greater share of the nut’s weight is edible kernel rather than shell.
That difference could help make black walnut production more commercially viable.
Decades of Research Focused on Better Nuts
The university’s black walnut research builds on decades of work evaluating trees for characteristics that influence their growth, production and market potential.
Revord says his predecessor, Mark Cogshall, spent about 15 years evaluating trees in this orchard and two others at the research farm. The work examined phenology, including when trees break bud in the spring, produce flowers and bear nuts, as well as how production changes from year to year.
Researchers also evaluate the nuts themselves, measuring shell thickness and weight, kernel size and the percentage of each nut made up of edible kernel.
“All those things come together to make recommendations for growers,” Revord says.
The research farm spans 600 acres, with more than 100 acres dedicated to active research plots. Located near the Missouri River, the farm includes a mix of forest, varied terrain and floodplain areas. Across its repositories and breeding populations, the farm has more than 15,000 trees, Revord says. The research extends beyond black walnuts to include chestnuts, hazelnuts, pecans and other agroforestry crops.
Could Black Walnuts Offer Another Income Stream?
Missouri has a significant role in the black walnut industry. The state accounts for about 20% of the native-range black walnut trees in the United States, making it an important location for research into the species’ potential.
While black walnuts are traditionally valued for their timber, improved nut-producing cultivars could offer landowners another way to generate revenue from their acreage.
The time required to produce a crop remains an important consideration. For Hickman specifically, Revord says it may be possible to collect seed or begin propagation as early as five years after planting, although that timeline can include nursery production rather than harvesting nuts from an established orchard.
A more typical timeline can be 10 years or longer. Even so, Revord sees potential for black walnuts to complement other farm enterprises, particularly on land that may be less suitable for conventional row crops, and create more economic opportunity for landowners.
“That’s a perfect application for this,” Revord says. “If you’re gonna adopt something like Eastern Black Walnut, you’re probably not gonna adopt it from fence row to fence row, but it could be a really nice compliment, especially on bottom-land acreage that could be more prone to flooding because they can be a bottom-land species, kind of like pecans.”
That approach could allow landowners to diversify portions of their operations without converting all their acreage to a new crop. The goal is not necessarily to replace black walnut timber production, but to explore whether growers can capture value from both nuts and wood.
“It’s certainly not going to replace attention on the timber value and you might be able to have a dual-purpose orchard with the right kind of management,” Revord says. “Where you know at the end of that orchard’s life you could still derive timber value out of it. But along the way you have a crop from the nuts.”
Researchers Begin Releasing New Cultivars
The University of Missouri’s long-term research is now moving toward a new phase: helping establish a more standardized black walnut nut industry. Revord says researchers estimate that about 5,000 acres of orchards could be needed to displace the existing supply targeted by their production model and create a new economic opportunity for growers.
“That’s the first goal,” Revord says. “And we just started releasing cultivars from our program, which is 30 years old, to support that adoption.”
The release of cultivars selected for desirable traits could give growers a more reliable starting point than relying on naturally occurring trees with variable nut characteristics. However, developing a new crop industry takes time. Researchers must continue evaluating trees, refining selections and determining how the cultivars perform under different growing conditions.
“We’re 24 years into planting progeny and evaluating them, you know, from the time that the first one was planted, and we’ll need to keep pushing forward for a few decades to fully realize the potential of the species,” Revord says.
For farmers and landowners looking for additional income opportunities, the research could eventually help turn a tree long valued for its timber into a dual-purpose crop, and one that produces nuts during its productive life while retaining potential timber value for the future.
