Lumber prices, which shed more than 20% in August, have continued to fall to start September, hitting their lowest price this year thanks to a glut of wood that was piled up ahead of a big increase in duties on Canadian imports. “There has clearly been a speculative inventory accumulation at every level from mills to single location lumber dealers,” said Matt Layman, who publishes Layman’s Lumber Guide “For the first time in my 40-plus year career there is indeed a wall of wood that must be liquidated.” As with many raw materials, the lumber market has been whipsawed by President Trump’s tariff threats. The White House is studying tariffs on imported lumber in the name of national security. …Any lumber tariff will come on top of duties on Canadian softwood lumber that rose to about 35% for most producers, from 15% last year.  [to access the full story a WSJ subscription is required]