The man who would be king has turned tree-hugger on YouTube. Prince William has made a videotaped plea to Brits to pick their favorite green spaces for protection. Local authorities have chosen several sites for protection as part of the Queen Elizabeth II Fields Challenge, which is aimed at blocking development at popular open areas, notes the Telegraph. Too many sites have been nominated, however, and William urges Brits to vote on their favorites online. "Many of these sites may be lost in the future if they are not protected," warns the 29-year-old prince. "Protecting these sites will mean that millions of people for generations can take part in sport, play, and enjoyment." William's message comes on the heels of the British government's proposed planning reforms, generally viewed as paving the way for new development. (More Britain stories.)