PC 602.2

602.2. Any ordinance or resolution adopted by a county which
requires written permission to enter vacant or unimproved private
land from either the owner, the owner's agent, or the person in
lawful possession of private land, shall not apply unless the land is
immediately adjacent and contiguous to residential property, or
enclosed by fence, or under cultivation, or posted with signs
forbidding trespass, displayed at intervals of not less than three to
a mile, along all exterior boundaries and at all roads and trails
entering the private land.