** Shares of lumber companies fall after U.S. President Donald Trump said on Monday he was slapping 10% tariffs on imported timber

** "Imposing new tariffs under Section 232 is misguided and unnecessary. These tariffs will not improve U.S. national security — they will only drive-up lumber costs," says BC Lumber Trade Council President Kurt Niquidet

** Canadian lumber companies: Interfor Corp IFP.TO and Canfor CFP.TO each down 1.1%, West Fraser WFG.TO down marginally, Acadian Timber ADN.TO down ~1%

** Boise Cascade BCC.N and Weyerhaeuser WY.N both down marginally

** "We expect the full tariff impact to be shouldered across the housing value chain as we move into 2026," - UBS analysts

** Raymond James analyst Daryl Swetlishoff says that Canfor remains the most exposed Canadian lumber producer

** "We expect curtailments and reduced U.S. exports to balance markets - supporting price hikes approaching Canadian cash costs" - Raymond James

(Reporting by Pooja Menon in Bengaluru)

((Pooja.Menon@thomsonreuters.com;))