To chart the seasons, look to tree leaves. To understand the past, look inside to the tree’s rings. Valerie Trouet, associate professor in the Laboratory of Tree-Ring Research at the University of Arizona, joins host Krys Boyd to talk about what we can learn by looking inside tree trunks – everything from the science of climate change to momentous occasions in human history. Her book is called “Tree Story: The History of the World Written in Rings.”