ALBUMLast Leaf on the Tree, Willie NelsonLegacy Recordings, November 1Opening his 153rd album with a cover of Tom Waits’s “Last Leaf,” Willie sings wistfully, “I’m the last leaf on the tree / The autumn took the rest / But it won’t take me.” It’s not the first time the 91-year-old country legend has pondered mortality, but the autumnal allusions and themes of transition and transformation in his covers of the Flaming Lips’ “Do You Realize??” and Warren Zevon’s “Keep Me in Your Heart” are particularly poignant. Credit for much of the album’s success goes to Willie’s son Micah Nelson, who produced the record, created its cover art, wrote one of its songs, and cowrote another with his dad. At the time of year when leaves…