By Hannah Hunt
The Ecological and Economic Importance of the Quercus Collection at Bernheim
“A thing is right when it tends to preserve the integrity, stability, and beauty of the biotic community. It is wrong when it tends otherwise.” – Aldo Leopold; A Sand County Almanac
When bourbon distillery founder and Louisville philanthropist Isaac Wolfe Bernheim purchased the original 14,000-acre property in 1929, it was severely depleted of nutrients due to intense iron-ore mining. But Mr. Bernheim saw the vision— pristine forest and a wide-open area to create an Arboretum that would draw visitors from around the nation to appreciate the beauty of Kentucky. Today, Bernheim Forest and Arboretum has increased in size by almost 3,000 acres, but our most promising feature remains space.
Most of the property is dedicated to the stewardship of a large block of native forest, but a roughly 600-acre portion of the property was cleared in the 1930-40s to make way for the Arboretum. The Oak Collection was one of the original Collections to be planted, beginning in the 1950’s. Currently, our oldest living Arboretum specimen is a pin oak (Quercus palustris) planted in 1952. Most of the Oak collection is located between the Big Prairie, a 34-acre managed grass and forb prairie, and the main Arboretum Loop, providing a shady respite and solidifying its status as a favorite among visitors. In recent years, we have been looking for opportunities to utilize our vast space and expertise to support oaks in Kentucky.
As part of the White Oak Project, we partnered with the University of Kentucky and Kentucky Division of Forestry for the Independent Seed Orchard Program (ISOP) to establish a half-acre white oak (Quercus alba) orchard. Our nursery received 100 seedlings grown from wild-collected acorns from across its native range and subjected to extensive progeny testing to determine the ideal candidates. When the trees begin to produce acorns, they will be sold back to the Kentucky Division of Forestry to be dispersed to stakeholders.
Stewarding and conserving oaks in Kentucky is important, not only ecologically, but economically as well. Much of the taste and all the color of bourbon is derived from being aged in white oak barrels. Unlike other spirits, barrels can only be used once. Luckily, the bourbon industry is already thinking ahead. Old Forester and Brown-Foreman employees visited our Arboretum to collect acorns for a research project with University of Kentucky before being planted in an in-ground nursery on site at the Brown-Foreman distillery in Louisville.
In addition to partnerships outside the organization, Bernheim is doing work to conserve oaks in our own backyard as well. Last year, we acquired 182 acres of natural land known as the Buffalo Creek Tract, which contains myriad species including Quercus alba (white oak), Quercus montana (chestnut oak), Quercus velutina (black oak), Quercus rubra (red oak), Quercus stellata (post oak), and Quercus marilandica (blackjack oak). These mature trees are especially important habitat for bats, which require standing dead trees for maternity roosts. Bernheim is home to 13 bat species, including the federally endangered Indiana bat and the northern long-eared bat.
To increase the capacity of our nursery to propagate and grow oaks and other important species, we partnered with Heaven Hill Distillery and Grow Appalachia to erect a high-tunnel capable of housing up to 250 one-gallon trees. “Our new greenhouse will play a vital role in preserving regional plant genetics by propagating species uniquely adapted to our local climate, soils, and ecosystems” said Casey Hammett, Nursery Manager.
While we love our native oaks, the Arboretum also supports conservation of ex-situ species as well. Three Quercus georgiana (Georgia oak) are scattered across the landscape, each healthy and producing acorns. This year was the second year we participated in an effort lead by the CREW (Conservation and Research of Exceptional Wildflowers (CREW) Plant Lab of Cincinnati Zoo & Botanical Garden to study oak conservation through cryopreservation. By sending shoots from the same trees yearly, researchers can analyze species, genotypes, habitats, environmental conditions, and weather patterns. This partnership involves 18 different institutions and three labs across the United States and Mexico, representing a comprehensive effort of significant collaboration across the country to enhance the conservation of oak species.
Most recently, Bernheim Forest and Arboretum received accreditation from the Plant Collections Network for our Oak Collection, following the accreditation of our Magnolia Collection last year.
“Bernheim belonging to a multi-site conservation effort for Quercus should act as an example and inspiration to every garden and arboretum, no matter their size or budget to find a scientific and cooperative way to contribute to the conservation of a plant group. So many plant species need conservation assistance”, observed Dr. Mark Wourms, President/CEO.
The process helped us to focus our goals, both for the Collection but also the institution, while providing a framework showcasing the meaningful work that is already being done by our partners in the public gardens world. We are thrilled to be the newest addition to the Quercus Multi-Site Collection and look forward to sharing our expertise, passion, and resources for the common goal of conservation of this keystone species.
Editor’s Note: This article was originally published in Public Garden, the journal of the American Public Gardens Association, Volume 1, Issue 1, 2026. View the publication.
Read the announcement, Oak Collection Receives Accreditation from American Public Gardens Association, October 15, 2025
