It's peak leaf-peeping season, and Cidiot® and Kaatscast have teamed up to release foliage episodes the same week. Kaatscast covers the west side of the Hudson; Cidiot's got the east.

In this episode, Mat Zucker sits down with Amy Zanne, senior scientist at the Cary Institute of Ecosystem Studies in Millbrook, to answer the question every leaf peeper has: why do leaves do this?

Amy — a botanist by training and a recent Hudson Valley transplant by way of New Hampshire — breaks down plant science behind fall color: the pigments that make leaves orange, yellow, red, and purple, why trees drop their leaves at all, how they scramble to reclaim nutrients before winter, and what causes a leaf to let go and fall to the grou ...