In the age-old battle of man versus nature, nature usually wins. It sure seems to be winning in North Wildwood, a Jersey Shore town grappling with severe erosion that has wiped out part of the dunes protecting $2.5 billion worth of private property. The city wants emergency approval from the state to build a bulkhead to close the gap, even as it sues the state to recover the $30 million it says it has spent trucking in sand to widen eroded beaches. The state has fined North Wildwood $12 million for unauthorized work on the beach, and no end is in sight to the dispute.