The surest way to kill a tree is to give a donation to the Audubon Society, World Wildlife Fund or almost any other major environmental organization. You don't need to give a lot, even $10 will do. Not only will you kill trees; you'll waste water, pollute the air, and increase your carbon footprint.
Why does contributing to an environmental organization have such an adverse effect. Quite simply, they won't give you an option to be excluded from their mailings and once they know you're a donor they'll flood you with mail. Anything to raise that incremental dollar.
Not only will they flood you with mail, but to maximize the impact on the environment they'll pimp your name to every other environmental organization on the planet and those organizations will bury you in paper too.
So, this year, to save the environment, I'm donating to other causes and I'll be lobbying environmental organizations to change their practices.