Tapping into the science of maple syrup

What makes tree sap start running in late winter? And how do you tap a tree without harming it? MPR News host Angela Davis talks about the science behind maple syrup, how climate change is affecting the sap season in Minnesota and what trees may better withstand climate change. Guests:Laura Irish-Hanson is an extension educator at the University of Minnesota.Brandon Miller is an assistant professor of horticulture and curator of Plant Collections at the University of Minnesota Landscape Arboretum.