Blandy Experimental Farm: Saving the Butternut Tree

T'ai Roulston is the Curator of the State Arboretum of Virginia and a research associate professor in the Department of Environmental Sciences. The State Arboretum of Virginia is part of the University of Virginia, located 2 hours north of Charlottesville in the Shenandoah Valley at one of UVA's three ecological field stations, Blandy Experimental Farm.

In 1926, the University of Virginia received 712 acres of agricultural land through a bequest from New York stockbroker Graham Blandy and established a research field station known as Blandy Experimental Farm ("Blandy"). Blandy's first director, Orland E. White, soon established an arboretum on the property that is known today as the State Arboretum of Virginia.  Like most plant collections at the time, the arboretum showcased unusual plants from around the world and sought to learn what plants of horticultural interest could survive the local climate and geology. Can English ivy survive here and gracefully adorn our buildings like it does at Oxford?  Reveal: the answer is yes.

Moving plants around the world intentionally for horticulture and accidentally during shipping created two substantial problems that we face today. A proliferation of invasive species that can change the ecology of our landscapes, and the introduction of new insect pests and diseases that target native plants that have little defense against them. Among such diseases, the chestnut blight, which devastated vast forests of American chestnut trees, is likely the best known. I'm going to focus on a different story, however: the case of the disappearing butternut tree.

The butternut or white walnut (Juglans cinerea) is a nut-producing tree native to the eastern United States and long valued culturally by indigenous peoples and later settlers as a producer of dyes, syrup, edible nuts, and fine wood. In the 1960s, a new disease called butternut canker was found on butternut trees in Wisconsin and quickly swept through the entire natural range of butternuts, infecting most trees and eventually killing them. Researchers, mainly from the USDA and Purdue University, have long sought to find wild trees resistant to the disease, scouring the forests for healthy trees to test. While variation in natural resistance has been found, no fully resistant trees have been discovered or bred into a line of trees ready for reintroduction to the wild. The State Arboretum has decided to join these efforts to conserve a declining native tree.

Virginia is one of the least studied states for genetic diversity, distribution, and resistance in butternut trees, based on the work done at Purdue. Yet, Virginia still has butternut populations across a large portion of the state (mainly from the Appalachian region west to the border), especially along rivers, field edges, and ridgetops where the canopy remains open. For the last 2 years, we have been following leads from property owners and natural resource specialists about where to find butternut trees, then going to the property, examining tree health, and collecting leaf samples for genetic analysis and nuts to propagate in our own butternut orchard.

We are planning to start a bigger project next year in which we reach out to individuals across the state, asking them to find the tree and having them take photographs of the trunk and nuts and send them in. Based on the photographs, we're hoping to recognize which trees appear healthy and are currently producing nuts, and that should give us some candidates for resistant trees.

Proving resistance will take years. We'll grow trees from the nuts for several years, then challenge them with different strains of the disease and assess them for resistance in a common environment. Hopefully, we'll find some evidence that there are trees adapted to our local climate with enough inherent resistance to form the basis of a breeding program. Finding those trees in the wild is going to take a lot of looking, and that is why partnerships between researchers and landowners, and people who simply like to walk in wild areas and identify trees are a crucial first step to saving a tree that is rapidly declining.

If you know where to find butternut trees, please reach out to me. The trees can be found with some regularity in some parts of the state, including Albemarle and Greene County, but they are usually exhibiting symptoms of canker. This is a clear case where a large community of searchers is necessary for the science to have a chance of succeeding. You can be part of that community.