It might also have something to do with the fact that Canadian lumber companies have been buying up US mills, whilst closing the ones they own in BC. 

Interfor, Canfor, West Fraser Timber Company.

How's this for vested interests..." B.C.’s largest forestry company, West Fraser, now owns 15 American sawmills, compared with just seven in B.C. and five in Alberta. About 36% of its shipments of lumber now come from its U.S. mills, said Rodger Hutchinson, West Fraser’s vice-president of investor relations."

Canfor?   "Owns 12 sawmills in B.C., one in Alberta and 10 in the U.S."

Not just Clark abandoning BC businesses, our Canadian lumber companies are too.