Pity there are no trees in Western Canada

Christmas trees, The Real Canadian Store, Grandview Highway, Vancouver, BC

Product tag on christmas tree, The Real Canadian Store, Grandview Highway, Vancouver, BC

Western Canada is awash with trees, a fact included in Monty Python's "Lumberjack Song" ("As they float down the mighty rivers of British Columbia".)

Yet with all of the evergreen trees available in Western Canada there are evidently none that can be used as Christmas trees. So The Real Canadian Superstore has to import Christmas trees from Oregon. Kirk, a Tacoma, Washington-based firm serves all of western North America from it operations in Oregon. (Operations in North Carolina, and Nova Scotia serves the east.)

My question is, why can't Canadians grow Christmas trees for customers in Vancouver?