Possibly the most popular form of activism on Earth Day -- or around Earth Day -- is the planting of trees. It's a great way to get in touch with nature and fight back against polluters.
Plus, it looks nice. And that's why we get plenty of photo-ops with celebrities planting trees. [See Bill Clinton and the Obamas planting trees for Earth Day 2009] Here are a few from the last couple of years (and one from the '90s -- you'll know which).
Also -- who knew former President Bush spent so much time planting trees?
Check it out: