Jolie Holland must have wondered if she’d done the right thing when she quit the Be Good Tanyas. Having co-founded the group, she left before their debut album and has spent the last three years sitting in San Francisco watching them become the new champions of roots music. Catalpa, her solo debut, perhaps explains her decision. She must have thought the Tanyas’ pared-down acoustics were overblown, for her own debut is like a field recording, full of hiss and crackle as she sings her spooky fairy tales over an acoustic guitar, accompanied occasionally by a muted banjo and meandering harmonica. And therein, of course, lies its back-porch appeal.