West Fraser Timber Co. Ltd. said Wednesday it expects demand for its timber products will grow in North American and Europe.    On the N. American markets outlook:      Several key trends that have served as positive drivers in recent years are expected to continue to support medium- and longer-term demand for new home construction in North America, according to West Fraser. "The most significant uses for our North American lumber products are residential construction, repair and remodelling and industrial applications. Over the medium term, improved housing affordability from stabilization of ...