There are two major acts of violence against nature involved in Christmas tradition. Selling living carps, which are one of the most important dish during Christmas Eve and cutting hundreds of thousands firs and pines for Christmas Trees. Most ironic is that Christmas Tree is a symbol of reborn, living and fertility, while - after decorating our houses for few days - it is mostly thrown out in the garbage. Although many people don't bother that, maybe it is a good time to start “a new secular tradition”. It doesn't cost much yet it makes difference.
What are the alternatives?
First – not to buy a living carp. Bought dead one would taste the same and you wouldn't have to practice killing a being right before you celebrate Jesus birthday with your family. (Personality, I truly believe that most people don't like killing).
Secound – use an artificial plastic Christmas tree (which would decompose thousands of years) or one of the recyclable one.