Paul W. Meyer is the F. Otto Haas Director of the Morris Arboretum at the University of Pennsylvania. Throughout his career, he has been a passionate observer and promoter of trees throughout the Philadelphia region. Catriona Briger has a master's degree in landscape architecture and currently freelances in Philadelphia as a designer, editor, and writer. Edward Sibley Barnard is an editor and an author of several books on natural history, including the Columbia University Press titles Central Park Trees and Landscapes: A Guide to New York City's Masterpiece (2016) and New York City Trees: A Field Guide for the Metropolitan Area (2002).