The scale of Guthrie's self-deprecating wit may have been an eye-opener for a crowd who, while clearly familiar in a rose-tinted sort of way with his clutch of classics from a long time ago, had almost certainly never seen him live. Or assumed he was dead. Rambling humour, though, has always been part of Guthrie's oeuvre.
The son and heir of Woody Guthrie - dust-bowl balladeer, rights activist and composer of America's alternative national anthem "This Land Is Your Land" - Arlo has built up an eclectic catalogue of work which shares the essence of his father's values but adds spirituality, musical magpie-isms and idiosyncrasies by the truckload.
It's something of an albatross to the man that he's still known today for his first, biggest and longest record, Alice's Restaurant, released in 1967, a 20-minute musical broadsheet about trying to dump some garbage on Thanksgiving Day and later made into one of those "of its time" films. Well, nobody else had done it before or since - and Arlo certainly wasn't going to do it tonight.
Instead, he turned in a fabulously entertaining set of songs that included, bizarrely, virtually everything from the flip-side of that first record - beautiful, long-overshadowed songs like "Chilling of the Evening" and "Highway in the Wind" - plus a handful of latterday gems, including Steve Goodman's "City of New Orleans".
He read a poem about a moose, from a recent book project entitled Assorted Moose Poems, which had just, he informed us, gone to a second printing "'cos another guy wanted one...".
Although astute enough to bond with his still largely Woodstock generation audience through ribald nostalgia, and although the new songs still sound like the old ones (no bad thing, necessarily), Guthrie's heart is in the present - much of his personal earnings go towards funding the Guthrie Centre for Aids and child abuse research.
He had just, he said, recorded two new albums. One is another bash at Alice "with historical footnotes", so he can stop playing it on-stage. He did play three songs from the other, Mystic Journey, though - two as good as anything he's written, the third, "Doors of Heaven", a well-meaning but horribly "Imagine"-esque piece of whimsy that will probably be a minor hit for somebody.
He was called back to the stage three times before signing off with the gorgeous, implausibly titled "Gabriel's Mother's Hiway Ballad # 16 Blues", and that perennial end-the-encores gambit "Goodnight Irene".Reuse content