Trade can be affected by other factors.
Businesses sometimes are subjected to strong criticism from environmental groups. The Canadian government addresses this type of issue by developing environmental side agreements with its trade partners.

European timber producers are willing to support local environmentalist demands and boycott lumber imported from Canada. If Canadian lumber fails to sell in Europe, Europe will import less. This means European timber producers will have less competition.
The issue of human rights complicates international trade relations. Canadians feel we have an obligation to fight human rights abuses wherever we might find them. Canada tries either to restrict trade with countries that don't share its views on human rights, or to influence trade partners to improve their records in this area.

In Canada, the delay in trade negotiations with China has more to do with Chinese human rights violations than with tariffs. 

But don't be deceived. Not all human rights legislation is actually enacted in the name of human rights. In the United States, the Helms-Burton legislation has more to do with profit-driven U.S. sugar and tobacco producers than with human rights violations in Cuba.