It used to be the fate of a used Christmas tree to end up in a landfill. If you have bird feeders, place the tree near them. Birds waste a lot of body heat trying to keep warm in exposed areas. The protection will help them get through the winter. It lays on the ground forever, until blown away, so it is worth the time to try and take it off the tree, even though it is hard to do on a dry tree.
Some lakes have no structure, meaning a flat bottom or no weed beds.
Placing old trees in specific areas of the lake gives a place for minnows and crappies to hide, live and grow, and attracts the bigger fish who eat them. It helps the food chain. Kelly advises people to check with the Department of Natural Resources before doing that. The Boy Scouts used to come in every year and do that project for us, but since everything is pretty intact now, we haven't needed it done for a few years. Tuthill grinds up the trees and enhances the chips with cow manure.