By Hannah Hunt
What do these trees have in common?
The maidenhair tree (Ginkgo biloba), franklin tree (Franklinia alatamaha), American chestnut (Castanea dentata), and bald cypress (Taxodium distichum) were once near extirpation but have made a resurgence, partially thanks to Arboreta around the world exchanging genetic material and supporting the populations of these sensitive plants.
An Arboretum acts as a living library of genetic material, where the more backups there are, the safer that material becomes. Bernheim’s 600-acre Arboretum has over 3,500 accessioned plants encompassing 1,892 taxa. As a Level 4 Arbnet and BGCI-accredited arboretum, as well as a nationally accredited collection holder, we collaborate with other arboreta—such as the U.S. National Arboretum, Dawes Arboretum, Atlanta Botanical Garden, Rutgers University, and Cornell University—to help preserve global biodiversity.
Collections can be categorized as in-situ or ex-situ. In-situ conservation focuses on protecting plant populations in their native habitat. For example, the American chestnut, native to Kentucky, is grown in Bernheim’s Arboretum from wild-collected germplasm, representing an in-situ strategy. In contrast, the Franklin tree, native only to Georgia’s Altamaha River Valley, hasn’t been observed in the wild since 1790. Its decline is attributed to theories such as a soil pathogen linked to cotton farming, over-collecting, or its inability to adapt to the southern climate after glaciation. Because of these factors, cultivating Franklin trees outside their native habitat is considered safer and an example of an ex-situ conservation strategy.
As an Arboretum and Botanical Garden, Bernheim cultivates plants from around the globe, including rare and endangered species. Approximately 70% of the Arboretum consists of native trees and cultivars, while the remaining 30% includes exotic species that thrive in Kentucky. There is an important distinction between non-native, or exotic, species and invasive species. Bernheim continuously monitors our collections for any species that may exhibit aggressive growth; if identified as problematic, they are removed. Additionally, changing weather conditions due to climate change can sometimes affect the invasiveness of certain species.
To explore these endangered species and more in the Arboretum, visit our plant database.
