Export tax (called export charge) only applies to exports of softwood lumber products to United States. Certain softwood lumber exports are excluded:.• produced from logs harvested in the Atlantic provinces,.the origin of which is certified under the Maritime Lumber.Bureau Certificate of Origin;.• from logs harvested and produced in the Yukon,.Northwest Territories or Nunavut;.• from 32 companies previously found by U.S. authorities.not to benefit from subsidies; these include all the.Quebec border mills.