No doubt California's ongoing drought has taken a toll on the environment and yet it can be hard to discern just how serious that toll is. 

A new report published this week in the Proceedings of the National Academy of Sciences finds that 58 million trees might be in peril thanks to this long dry spell.

For more on this and what it means for the future of California Alex Cohen speaks to the the study's lead author Greg Asner, an ecologist at the Carnegie Institution at Stanford University.

To hear the entire conversation click on the audio embedded at the top of this post.