Canada's boreal forest is the world's largest intact forest ecosystem -- but it's shrinking fast as we chop down a million acres of ancient trees per year to make throwaway tissue products such as toilet paper and paper towels. Costco can help stop the destruction by only selling tissue products made from recycled materials. I urge Costco to 1) make its Kirkland Signature tissue products from at least 50 percent recycled materials, and 2) refuse to sell other brands of tissue products until they implement the same change.