Softwood lumber production by U.S. sawmills in the first four months of 2018 was 11.579 billion board ft. (bbf), a year-over-year increase of 5.5% from 10.980 bbf in the same period last year.  Western U.S. sawmills contributed 4.899 bbf to the four-month total, up 10.0% from 4.455 bbf a year earlier, while production at southern U.S. sawmills gained 2.1% to reach 6.134 bbf, up from 6.005 bbf last year, reported the Western Wood Products Assn. in its latest Lumber Track report.   ...