Species identified as at risk of extinction require conservation action to ensure that they not only survive but are also resilient to the myriad threats they face. This entails protection of threatened wild populations of plants in their natural habitats, and ex situ conservation in botanic gardens and seed banks. Because oaks are “exceptional species” – their acorns do not survive the low temperature and humidity conditions of a standard seed bank – these species require alternative methods for effective ex situ conservation of genetic diversity. Living collections of trees and cryopreservation of embryos and vegetative (growth) tissues are two solutions to this challenge, but these require more time, expertise, and management than standard seed banking. Thus, oaks are in urgent need of a coordinated, global effort to efficiently and effectively preserve species and populations both in their native habitats and in ex situ collections.