I'm pretty sure you can put christmas trees in. I've heard of poeple doing that for a long time. And seen a story in the paper of DNR collecting them to make beds in the lakes. As far as the exact rules of where you can or cannot put them I would like to know myself. The only thing I would think that there may be some regulations on is how shallow they can be put, especially bambo if it was right under the surface of the water.