Why are trees and shrubs invading what's left of North America's prairies?

The largest portion of tallgrass prairie in the world is in danger.

Celia Llopis-Jepsen of the Kansas News Service explains why the Flint Hills of Kansas is being overrun by trees and how it’s impacting ranchers.

This story is from the podcast “Up From Dust” from the Kansas News Service and KCUR Studios.

This article was originally published on WBUR.org.