Hallucinatory Forest

When this spell is cast, a hallucinatory forest comes into existence. The illusionary forest appears to be perfectly natural and is indistinguishable from a real forest. Priests attuned to the woodlands — as well as such creatures as centaurs, dryads, green dragons, nymphs, satyrs, and treants — recognize the forest for what it is. All other creatures believe it is there, and movement and order of march are affected accordingly.
Touching the illusory growth neither affects the magic nor reveals its nature. The hallucinatory forest remains until it is magically dispelled by a reverse of the spell or a dispel magic spell. The area shape is either roughly rectangular or square, in general, and at least 40 feet deep, in whatever location the caster desires. The forest can be of less than maximum area if the caster wishes. One of its edges can appear up to 80 yards away from the caster.

Reverse: True Terrain

The reverse of this spell, true terrain, will dispel a hallucinatory forest or terrain, revealing the actual terrain that is being hidden, along with anything hiding within.

Reversible

Sphere: Plant
(Illusion/Phantasm)
Level: 4

Range: 80 yards
Components: V, S
Duration: Permanent
Casting Time: 7
Area of Effect: 40-foot square/level
Saving Throw: None