As in the ones laying on the ground around the temple. I guess they're supposed to magical cursed vines or something? I mean, entangling is one thing, but 1d6 per round in addition to that is a bit much.
Like other types of surfaces, they seem too powerful relative to the DnD rules set, I suggest they just entangle, or maybe do 1 point of damage per turn... of course, if our characters were smart enough to navigate around them rather than trying to run straight though it wouldn't be such an issue.
It's would also be nice if we could burn them off (or even attack them) to clear the area.