Christmas trees make excellent habitat for birds and other wildlife if left outside after the holidays. If you have enough land, leave your tree out to decay naturally over time. If you know anyone with goats, talk to them--goats love to eat Christmas trees!
The Johnson, Stowe, and Worcester LRSWMD Drop-off Locations accept Christmas Trees for free.
As of July 2016 the State of Vermont bans the "knowing disposal" of this material.