Wizards, elves and dwarves are the creatures that star in T.A. Barron’s fantasy novels, but there’s also a more subtle character that runs throughout: nature. The author hopes his readers will pick up an appreciation and respect for the environment as they page through his latest trilogy, “The Great Tree of Avalon: The Child of the Dark Prophecy.” Host Steve Curwood talks with Barron about his own childhood, and the kids in real life who inspire his plots.