Daylight saving time is behind us, and spring is just around the corner. To celebrate, "On Second Thought" is reflecting on a Southern icon: The Quercus virginiana is Georgia's official tree. It's better known as the live oak tree and has held the title since 1937. These majestic, ancient trees are symbols of the South in postcards, films and online travel sites. Greg Levine, co-executive director and chief program officer at Trees Atlanta, stopped by the show to explain the history and nature