This question is stemming from the new artifact in the SoM, Living Deadwood Staff. With it forests can be moved around and whatnot which leads to questions regarding a unit in multiple forests at the same time.

The biggest one I think is if a unit is in multiple blood forests and get hit with a spell. Does the unit suffer one resolution of a blood forest attack and thats it, or is it resolved for each forest?

The description reads "Whenever a spell is successfully cast by (or at) a MODEL in a blood forest, all units..." which leads me to think its just the closest forest that goes nuts even though it may affect a unit. Or is there rules about the terrain that I am unable to find that states a unit can be affected by only 1 terrain at a time.