Vancouver, British Columbia, Canada, 23 October 2007 -- Ainsworth Lumber Co. Ltd. today announced that it will curtail operations at four oriented strand board (OSB) mills due to operating losses, log supply shortages, and a decline in orders.

• Cook, Minnesota, will immediately begin to operate on a reduced production schedule for an indefinite period. In addition, Cook will be closed 03 November through 25 November and 24 December 2007 through 01 January 2008.

• Bemidji, Minnesota, will operate on a reduced production schedule for an indefinite period beginning 29 October. In addition, Bemidji will be closed 17 November through 09 December and 24 December 2007 through 01 January 2008. As announced previously, Bemidji is closed 19 October through 28 October.

• Grande Prairie, Alberta will be closed 05 November through 12 November and 17 December 2007 through 01 January 2008.

• Barwick, Ontario will be closed 24 December 2007 through 01 January 2008.