President Trump said, “We don’t need Canada to make our cars. We don’t need their lumber because we have our own forests,” he said. “We don’t need their oil and gas.” Mr. Trump is wrong on all three, but we’ll focus on lumber. The U.S. doesn’t produce enough lumber to meet domestic demand and thus imports about a third of the softwood used in home construction, mostly from Canada. …Mr. Trump’s tariff threat has created uncertainty for lumber wholesalers and contractors that could delay rebuilding. The U.S. can’t ramp up lumber production in the near term to meet domestic demand, so contractors will have to eat the tariff cost on lumber from Canada or import more from other countries, which would be expensive. If Mr. Trump wants to increase U.S. lumber production, he could open up more federal land for logging. …More tariffs will punish Americans trying to rebuild. [to access the full story a WSJ subscription is required]