Your Old Christmas Tree Can Help Build New Dunes in Brigantine If you're Christmas tree is about to become a thing of the past, put it to good use and help the future of the dunes in Brigantine. Should you not be able to donate your no-longer-jolly tree to the Cape May Zoo, the City of Brigantine will gladly take it off of your hands. Brigantine has been building Christmas tree dunes for over 25 years. Workers lay the dry trees lengthwise to help catch sand and establish another level of dune protection. Each year, Brigantine Public Works decides where to build a tree dune, based on need. Discarded Christmas trees act like snow fences.