Weyerhaeuser is to shut a sawmill at Aberdeen and a pulp mill at Cosmopolis in Seattle with the loss of 342 jobs.
The company, which has posted a 52% drop in earnings, announced plans earlier this month to sell or close a pulp and paper mill in northern Saskatchewan which employs 690 people.
And chief executive Steve Rogel has warned there are more tough decisions ahead.
The company expects fourth-quarter earnings to be even lower in all business segments except real estate, mainly due to a seasonal drop in demand for wood products.
Mr Rogel said that in a world of weakening markets and tightening economics, there was no alternative but to close plants.
Net income for the third quarter was US$285m on net sales of US$5.6bn, down from profits of US$594m a year ago when net sales were US$5.7bn.
The company was also hit by a US$5m pre-tax charge related to timber damage caused by Hurricane Katrina.
About 300,000 acres were damaged out of 2.5 million acres owned by the company in Alabama, Louisiana and Mississippi.
Weyerhaeuser said that harvesting that timber will create safety and sawmilling challenges and it expects to spend an additional US$7m in each of the next two quarters for that harvest.
