For species with recalcitrant seed, including many large-seeded temperate trees such as oaks, ongoing genetic diversity loss associated with climate change-related population declines is an urgent issue. Recalcitrant seed cannot be stored through conventional seed banking. Therefore, to conserve species' evolutionary potential and maintain trailing-edge genetic diversity for future climate-adaptive restoration, seed must be out-planted into climate-safer locations. Participatory field gene banking averts the costs associated with field gene banking in a single location, by drawing on a range of partners to steward translocated seedlings into the future. We present a case study of such translocations for a California endemic oak.