CALGARY — A shareholder in Parkland Corp. is demanding a board shakeup as the Calgary-based fuel refiner and retailer looks into putting itself up for sale. Engine Capital LP, the New York activist hedge fund that owns 2.5 per cent of Parkland's stock, said in a news release Monday that the current board cannot be trusted to represent investors' best interests. Engine, along with major shareholder Simpson Oil, had been calling on Parkland to make major changes and weigh strategic alternatives, including selling the entire company. Parkland rebuffed that demand until earlier this month, when it said its intrinsic value was not reflected in its stock price and it would formally review options that also include a merger and asset sales or purchases.