A concept B corporation, Greendimes will keep you off junk-mail lists while planting one tree every month for each of its subscribers at a cost of $3 per month. There are free junk mail removal services, but none that provide active protection and they definetly dont plant any trees.
Think of how many people get junk mail. Total those people and plant one tree for every person. Using a one to one ratio and dividing by the average tree density, my cookie monster calculator tells me an area about the size of the golden horseshoe could be saved in Canada alone.