In a major shift, timber companies have stepped up logging operations in the South,where they face less regulation than in the carefully monitored forests of the Pacific Northwest. Timber harvests in North Carolina, Tennessee and 11 other Southern states of United States increased by 50 percent from 1977 to 1997, from 6.8 billion cubic feet to 10.2 billion cubic feet,according to the draft of a federal report, the Southern Resources Assessment.