Strong homebuilding activity in North America will mean tight wood supply and demand for several more years, according to the top executive of the world’s largest lumber producer.  “In the next five years, we see housing starts continuing to be strong and an industry that will be working hard to keep up with demand,” West Fraser Timber Co. Ltd. Chief Executive Officer Ray Ferris said Wednesday in a phone interview.  West Fraser sells about 30% to 40% of its products into the housing industry, according to Ferris, which means his outlook bodes well ...