X0202 4 2005-12-30 0000079716 POTLATCH CORP PCH 0001056916 WEYERHAEUSER WILLIAM T 601 W. RIVERSIDE AVE. SUITE 1100 SPOKANE WA 99201 1 0 0 0 Phantom Stock Units 50.98 2005-12-30 4 A 0 577.023 50.98 A 2008-01-01 2008-01-31 Common Stock 577.023 22025.051 D Phantom stock units are credited to the reporting person's account on the transaction date in accordance with the provisions of the Potlatch Corporation Deferred Compensation Plan for Directors and will be converted to cash and paid on a 1-for-1 basis with the issuer's common stock. Phantom stock units will be converted to cash and paid on the date previously elected by the reporting person in accordance with the provisions of the Potlatch Corporation Deferred Compensation Plan for Directors. Phantom stock unit beneficial ownership total includes phantom stock allocated to the reporting person's Deferred Compensation Account since the reporting person's last report. Phantom stock allocations in this report include meeting attendance fees, a quarterly dividend and quarterly retainer fees at prices ranging from $44.73 to $50.89 per share. Malcolm A. Ryerse, Attorney-in-Fact 2006-01-03