Want to build a truss, rafter, or joist? For years, your strongest softwood lumber option for several key design tests has been Southern pine. But on June 1, three design values will drop for Southern pine 2x4s that are visually graded at #2 and below. Forest Economic Advisors notes the downgrade will move Southern pine from the strongest to the weakest of species on those values. But such might not be the case in years to come, as other species are in the process of underdoing re-evaluations similar to the one that caused Southern pine's values to fall.