Liveoak

This spell turns an oak tree into a protector or guardian. The spell can only be cast on a single tree at a time; while liveoak is in effect, you can't cast it again on another tree. Liveoak must be cast on a healthy, Huge oak. A triggering phrase of up to one word per caster level is placed on the targeted oak. The liveoak spell triggers the tree into animating as a treant. If liveoak is dispelled, the tree takes root immediately wherever it happens to be. If released by you, the tree tries to return to its original location before taking root.