The Morton Arboretum, in collaboration with Botanic Garden Conservation International U.S., are conducing a global ex situ collections survey of six priority tree genera: Acer, Magnolia, Malus, Quercus, Tilia, and Ulmus, The genera encompass The Morton Arboretum's six nationally accredited collections through the Plant Collections Network. 

The Morton Arboretum kindly request plant records information from all gardens, public and private, with permanent tree collections of any of the above genera. This includes information on the origin of each specimen or accession. A full export (all accession fields recorded) is welcom, however please include at least these priority fields. 

Read about the project here.