It’s the grand, exotic trees that especially call to Julianne Skai Arbor — the ones with gnarled outgrowths, tangled roots or hollows into which she can crawl. She likes to drape herself across swooping branches or ease herself into small spaces, exploring the habits, curves and textures of the different species she seeks out around the globe and absorbing their life force. The Sebastopol resident’s affection for the trees of the world has evolved into a unique vocation, one that forms the basis of a new coffee table book that features photographs of the author posing nude, enmeshed or intertwined...