Final answer:
Quebec is Canada's main producer of pulp and paper, due to its vast forests and established industry.
Step-by-step explanation:
The province that is Canada's main producer of pulp and paper is Quebec. This province has large areas of the Canadian Shield, which provide vast forests for the timber industry, pivotal for supplying the raw materials for pulp and paper production. Quebec's abundant natural resources and its established industry infrastructure make it the leader in Canadian pulp and paper production. In addition to Quebec, provinces like British Columbia and Ontario also contribute significantly to this industry.