Former Democratic President Jimmy Carter said Tuesday that he agreed with President Trump's efforts to impose tariffs on lumber imports from Canada.

Carter said the reason was personal: his own family is involved in the timber business and owns about 1,800 acres of timberland.

"Timber sales are a major source of income for my own family, and we have suffered financially for many years from an unfair advantage enjoyed by our major competitor in this vital market," Carter wrote in a op-ed for the Washington Post.

The Commerce Department announced last month that it had determined that exporters of softwood lumber from Canada received subsidies of 3.02 percent to 24.12 percent and was therefore seeking countervailing duties from Canada through the International Trade Commission. Canada complained about the announcement, but Commerce Secretary Wilbur Ross said the determination was "based on the facts presented, not on political considerations."

Softwood lumber is used to build houses.

Carter applauded the move, saying that Canada had an unfair advantage because "the vast majority of its standing timber is owned by provincial governments, which are free to dump their timber at practically no cost in order to stimulate their forest industry." The U.S. timber industry, by contrast, is privately owned and therefore forced to sell its product at market prices, which Carter called unfair to his family business.

"Largely because of Canada's unfair trade, the prices we receive today are the same as when I was in office over 35 years ago, although expenses from planting seedlings, thinning, removing unmarketable trees, periodic controlled burning and timber severance taxes are much greater," Carter wrote.