Jennifer McElwain, Professor of Botany at Trinity College Dublin and Director of Trinity College Botanic Garden, will explore the evolution of trees and forests through geological time. When did the first true trees evolve? What is a tree? What can fossil plants tell us about the oldest forests on Earth? How did forests survive volvanic events, extreme climates, and meteorite impacts in Earth’s geological past? What climatic conditions allowed ancient forests to grow within the polar regions? By linking forests 350 million year past to present, Jennifer’s talk will show that trees are witnesses to climate change and examine what may be in store for their future in a warming planet.