Why did Canada trade with Europe during the eigtheenth century ?
The answer to this question depends on what one means by Canada, since there was no Canadian nation at this point. If one means the Europeans who set up colonies in Canada, first the French, and then, after the Seven Years War, the British, then the answer is that Canadians traded with Europe because they were colonies of European nation-states. They were set up largely for the purpose of trade, particularly the fur trade. On the other hand, if one means the numerous Native American peoples who lived in what is now Canada, the answer is that they traded with Europeans (different than Europe) because they stood to benefit economically, militarily, and politically through trade, which was almost synonymous with diplomacy in their culture.