Remember that trees are a renewable resource. Fresh orange slices or strung popcorn will attract the birds and they can sit in the branches for shelter.
Many communities utilize a wood chipper to make mulches for flowerpots.
Once the branches are removed, the tree trunk can be chopped for firewood. Large quantities of used trees make effective sand and soil erosion barriers. Sunk into fish ponds, trees make excellent refuge and feeding areas. Woodworking hobbyists can make a multitude of items including buttons, gavels, and candlestick holders from the trunks of recycled Christmas trees.