On Saturday, April 30 from 2 to 4 p.m., Bob Wells of Wells Tree & Landscape will lead an hour long walk beginning in the heart of Mapleton Preserve. He will offer basic ID techniques and explore the importance of trees to the environment and to our well-being, as well as the threats posed by climate change. Attendees should meet at Mapleton Preserve/D&R Canal State Headquarters, 145 Mapleton Road, Kingston.