For decades, the United States and Canada have sparred over whether Canada is dumping lumber in the US and unfairly competing. Since the latest agreement ended in 2015, the US raised tariffs and held them in trust until a new trade agreement is reached. That hasn’t happened yet but the winds are changing. Another agreement isn’t on the horizon for at least another 18 months but if it happens, Canadian producers could get some of the $6.1B USD currently held.
Source: https://www.theglobeandmail.com/business/article-canada-softwood-lumber-tariff-refunds/