White oak (Quercus alba) is important economically, ecologically, and culturally. However, the species currently faces a significant challenge: a low rate of seedling recruitment, the process by which seeds successfully germinate and grow into new trees.
“Vegetative competition from native and nonnative plants, along with environmental stressors such as drought and disease, make it increasingly difficult for young white oaks to establish themselves,” says Meg Staton, associate professor of bioinformatics and computational genomics in the Department of Entomology and Plant Pathology.
A recent breakthrough by Staton and her colleagues has opened promising new research avenues. For the first time, they have sequenced the full genome of white oak, providing insight into its genetic structure and evolution. The groundbreaking achievement will expand understanding of variation within the species, helping researchers to identify and utilize traits such as pest resistance and climate adaptability that can improve seedling survivability.
“While decoding the genome is a monumental development, the next step is identifying which genetic markers are critical for sustainability in challenging environments,” Staton explains. “By pinpointing these traits, we can support our forest ecosystems by developing new generations that are more resilient.”
Native to Tennessee and much of eastern North America, white oak is relied upon by a wide range of organisms, including mammals, birds, insects, and fungi. In addition to playing a key role in biodiversity, soil health, and carbon sequestration, white oak also is a highly prized hardwood used in products such as whiskey barrels at the iconic Jack Daniel Distillery in Lynchburg, Tennessee.
Staton co-led the study alongside Drew Larson at Indiana University, in collaboration with the University of Kentucky, the US Forest Service, the University of Tennessee, and others. However, their recent breakthrough is just one example of how UTIA is advancing forest sustainability.
Another is the Margaret Finley Shackelford Orchard Complex founded in 2001 by the Margaret Finley Shackelford Charitable Trust, the Hobart Ames Foundation, the Ames AgResearch and Education Center in Grand Junction, Tennessee, and the UT Tree Improvement Program. Dedicated to the development of seed orchards for twenty-one species of trees, primarily oaks, the complex is on more than a hundred acres at Ames Center. Across a range of bottomland and upland areas, researchers are conducting precision forestry experiments that enhance both ecological sustainability and timber production, including testing seedlings from a mixture of species within existing ecosystems.
“We plant highly characterized, pedigreed oak seedlings in small forest openings and leave them to fight it out with the explosion of herbaceous and tree competition,” says Allan Houston, research professor in the School of Natural Resources. “Traditional silviculture predicted absolute failure, but some species, such as cherrybark oak, are very competitive. Many of the planted trees are thriving to enrich the mature stand, a stand that would have had no oak. Currently, we have thousands of trees in these experiments, with the eventual goal of sowing seedlings in other areas where oak species are no longer present.”
Houston, along with Scott Schlarbaum, professor and director of the UT Tree Improvement Program, coleads the projects at the Shackelford Orchard Complex. Collected seeds are destined for the Tennessee Division of Forestry’s East Tennessee State Nursery in Delano, Tennessee, except for small amounts held back for research. While valuable data has been collected for almost two dozen species, three have shown exceptional success: white oak, water oak, and the highly competitive cherrybark oak.
These hardwoods are valued not only for wood products but also for their critical roles in local ecosystems. Genetic research on white oaks first began at Ames Center in 1973, with a white oak seed orchard established in 1998 and a second-generation test in 2001. Orchards of other species, such as Chickasaw plum, began more recently in 2017, with genotypes still being added to increase genetic diversity in the orchard. However, a producing seed orchard for cherrybark oak is already in place, and collection for nursery production is expected to continue in the coming years.
“Sustainable forestry depends on how we manage our resources within a shrinking land base available for forests and a burgeoning human population,” says Schlarbaum. “UTIA’s accomplishments in DNA decoding, seed orchard development, and precision forestry experiments will strengthen forest ecosystems and ensure their vitality for generations to come.”
The UT Tree Improvement Program has served Tennessee and the southern Appalachian region since 1959 through research, collegiate education, and contributions to the science of forestry.
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