In folklore and fiction there's a rich tradition of trees that talk, from Greek mythology to The Wizard of Oz. But that's make-believe, right? Well, maybe. Many ecologists now believe that trees are in constant communication with their surroundings. Linguists may roll their eyes at claims of ‘talk,’ or ‘language.’ But observing how trees interact helps us understand the limits of language.

Photo by David Baron via Flickr creative commons. Music by Josef Falkenskold, From Now On, Silver Maple, Imprisoned, Josef Bel Habib and Podington Bear. Read a transcript of this episode here.