WINMALEE, AUSTRALIA - APRIL 17:  Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge pose for a photo with Girl Guides after planting a tree at the Winmalee Guide Hall on April 17, 2014 in Winmalee, Australia. The Duke and Duchess of Cambridge are on a three-week tour of Australia and New Zealand, the first official trip overseas with their son, Prince George of Cambridge.  (Photo by Brendon Thorne/Getty Images)