Lumber prices that have dropped more than 20% over the past month are prompting one of North America’s largest producers to throttle back output by 12%. Interfor said Thursday that it would reduce hours and reconfigure shifts as well as lengthen holiday breaks and maintenance shutdowns at its mills in Canada and the US to reduce output by about 145 million board feet through year-end. Lumber futures, which had fallen 18 of the past 22 trading sessions rose in response. …Interfor, which has headquarters in BC, is among the big Canadian sawyers that have shifted operations into the US as duties and diminished log availability have put sawmills out of the money back home. About 50% of Interfor’s capacity these days is in the US South. Another 12% is Washington and Oregon, where mills compete fiercely with Canadian rivals to sell the same species of wood. [to access the full story a WSJ subscription is required]