Edison Format · March 2010
You do not choose when to activate this effect.
It automatically activates the first time the appropriate type of monster would be destroyed.
If the effect of "Spiritual Forest" is resolved once during a turn, it cannot be resolved again even if "Spiritual Forest" is negated and then stops being negated in the same turn.
If a face-down Beast-Type, Beast-Warrior-Type, or Plant-Type monster you control is attacked and flipped face-up by battle, the effect of "Spiritual Forest" is applied.
You do not choose when to activate this effect. It automatically activates the first time the appropriate type of monster would be destroyed.