OTTAWA — Canada’s decision to turn to the North American Free Trade Agreement for a solution to the latest softwood lumber dispute proves how critical the agreement’s dispute resolution mechanisms are to this country, a Canadian international trade expert said Wednesday. Canada on Tuesday asked a review panel under Chapter 19 of NAFTA to investigate the countervailing duties imposed. …Colin Robertson, a former Canadian trade diplomat, said Wednesday it’s no surprise Canada made the application despite political battles with the U.S. over the very existence of the Chapter 19 dispute mechanism. “It would not be logical for us not to use it and we had to use it within a certain time frame so of course we’re going to apply it,” said Robertson. …Robertson said trade agreements were pursued by Canada… “to give us some relief from unfair application – and I stress unfair – of American trade law.”