definition of "lower Puna"

[ScottEF]

Hi, I'm a newcomer so forgive me if this is a dumb question or one discussed elsewhere. But since the 2018 lava news using this term frequently, I've wondered if there's any precise definition of "lower Puna." I gather it means, roughly, Pahoa and anything you can only reach on road by going past/through Pahoa, or even more informally, the lower-elevation parts of Puna. Does anyone ever use it more precisely than that, e.g., is there some point on the Keaau-Pahoa road where one might say "lower Puna starts here"?