Book excerpt: Mike Sullivan loves his adopted city of San Francisco, and he loves trees. In The Trees of San Francisco he has combined his passions, offering a striking and handy compendium of botanical information, historical tidbits, cultivation hints, and more. Sullivan's introduction details the history of trees in the city, a fairly recent phenomenon. The text then piques the reader's interest with discussions of 71 city trees. Each tree is illustrated with a photograph--with its common and scientific names prominently displayed--and its specific location within San Francisco, along with other sites; frequently a close-up shot of the tree is included. Sprinkled throughout are 13 sidelights relating to trees; among the topics are the city's wild parrots and the trees they love; an overview of the objectives of the Friends of the Urban Forest; and discussions about the link between Australia's trees and those in the city, such as the eucalyptus. The second part of the book gets the reader up and about, walking the city to see its trees. Full-page color maps accompany the seven detailed tours, outlining the routes; interesting factoids are interspersed throughout the directions. A two-page color map of San Francisco then highlights 25 selected neighborhoods ideal for viewing trees, leading into a checklist of the neighborhoods and their trees.