In this episode of Conservation Conversations, Sean speaks with Dr. Murphy Westwood, Vice President of Science and Conservation at the Morton Arboretum, which recently collaborated with NatureServe and other organizations to create a comprehensive assessment of trees in the United States. Find out how many trees in the U.S. are threatened with extinction, what really makes a tree a tree, and how botanic gardens inspire and educate 500 million people around the world each year.