Interfor is reporting a net loss of more than $20 million in the second quarter.
The company owns sawmills in Grand Forks and Castlegar.
It says export duties and falling lumber prices contributed to its loss.
It also pointed to a 13-day shutdown in Castlegar as part of a $50 million modernization.
However Interfor says the project is on time and on budget and should be finished by the end of the year.