Lawmakers are scrambling to save the summer concert season from federal agents poised to seize the instruments of rock and country stars because the wood used to make them may have been illegally harvested--and without their knowledge. “I don’t want the musicians from Nashville who are flying to Canada to perform this summer to worry about the government seizing their guitars,” said Tennessee Republican Sen. Lamar Alexander. Alexander, whose state is home to famed Gibson Guitars used by bands and stars like Van Halen, the Allman Brothers, Sheryl Crow, Ted Nugent and Paul McCartney, said Friday that he and Oregon...