Trees, nature’s largest and longest-lived creations, play an extraordinarily important role in our cityscapes. These living landmarks define space, cool the air, and connect us to nature and our past. Today, four out of five Americans live in or near cities, surrounded by millions of trees that make up urban forests. But most of us take them for granted and know little of their natural history or civic virtues.

On Thursday, December 8 in the Hunnewell Building of the Arnold Arboretum, author and historian Jill Jonnes will speak about the history of the tree in American cities over the course of the past two centuries, delving into the presidents, plant explorers, visionaries, citizen activists, scientists, and nurserymen whose arboreal passions have shaped and ornamented the nation’s cities. The Arboretum is located at 125 Arborway in Jamaica Plain, and the cost of the lecture is $10, free if a member of the Arnold Arboretum, or a student. To register visit www.my.arboretum.harvard.edu.