Julia Butterfly Hill climbed down from the tree she named Luna 10 years ago this December. After 738 days, and surviving an El Niño winter on the tip of a redwood, her protest turned Hill into an international symbol for environmental activism. Since then, she's become an inspirational speaker (some 250 events a year), a best-selling author and the co-founder of the Engage Network, a nonprofit that trains small groups of civic leaders to work toward social change. Now the 35-year-old, based in the East Bay for seven years, is taking a step out of the public eye and moving...