When it's time to discard your fresh Christmas tree after the holidays, be sure to give it a thorough inspection first. Make sure anything artificial -- string, tinsel, ribbon, ornament hooks -- is completely off the tree. Since most communities turn fresh trees into mulch, these plastic and metal bits and pieces can get shredded and inadvertently blended into the organic mixture. These small bits of trash can end up washing into creeks, then rivers, and eventually into lakes and oceans, where they cause pollution. If you want to take an even bigger step, avoid putting anything plastic on the tree to begin with. Decorate with natural materials and keepsake ornaments you know will never have a chance of accidentally being left on the tree come Dec. 26.