Ex situ conservation of American chestnut (Castanea dentata (Marsh.) Borkh.) and butternut (Juglans cinerea L.), a review

Two tree species native to North America, American chestnut (Castanea denta ta (Marsh.) Borkh.) and butternut (Juglans cinerea L.), which have experien ced rapid declines in their populations due to similar stressors (disease a nd changes in land use), are used as examples of how these species would be nefit from ex sial conservation efforts. Current and past ex sial and in si tu conservation efforts for these species are discussed and the focus of th is review is on two key research areas: 1) what needs to be preserved (gene tic information) and 2) how to preserve these trees or germplasm.