WASHINGTON, D.C. — The lumber war is heating up and Canada is bracing for an announcement that the U.S. is preparing to slap retroactive tariffs against Canada’s wood exports.

The U.S. Department of Commerce is expected to rule that Canada’s lumber producers have been flooding the U.S. market since the expiration of the Softwood Lumber Agreement in March.

Once that decision is officially announced, Canadian lumber producers will be required to post bonds on all wood shipped to the U.S. to cover potential tariffs.

Canadian Trade Minister, Pierre Pettigrew visited Washington last week, in an attempt to persuade U.S. trade representatives and commerce officials to reconsider their methodology.