Why was Canada known as the "arsenal of democracy"?

In a speech to the American public on December 29, 1940, President Roosevelt outlined the United States' role as an industrial giant, and defender of democracy, whose resources must now gear to war production.  This was the beginning of his plan for "Lend-Lease" whereby American industry would manufacture war materiel and loan or give it to Great Britain, who at that time (1940) was the ONLY country fighting Germany.  In his speech, Roosevelt stated:  "We must be the great Arsenal of Democracy......We have furnished the British great material support and we will furnish far more in the future."

Canada, part of the British Commonwealth, began to shift industries to a war footing as well, and Canadian ports became the major centers of departure for Canadian and American war materiel to Great Britain, as the journey crossing the Atlantic was shorter than from American shores.