A fire that consumed a centuries-old redwood in Samuel P. Taylor State Park was human-caused and probably the result of illegal camping, officials said. Last Thursday just before noon, Marin County firefighters and state park rangers responded to a blaze engulfing the Pioneer Tree, an 800-year-old landmark that was one of the largest old-growth redwoods in Marin. By the afternoon, firefighters had the flames under control, but the tree, a 200-foot giant ringed by smaller…