Wanna be a literal treehugger, but don’t wanna pay for the privilege? Planting a tree can be as easy as clicking “follow” on Twitter. Here are three free and easy ways to help reforest the world a little:

>> Follow a tweeter. The United Nations Environment Programme wants you reading its tweets — so much so that the org will plant a tree for every tweeter who follows @UNEPandYou [1] until June 5, which happens to be World Environment Day 2009 [2].

>> Join Plant A Free Tree [3]. This new eco-thinking website’ll plant a tree, via Trees for the Future [4], for every new person who becomes a member. The goal: To plant at least one million trees in 2009.

>> Ask your city for a tree. Many cities offer free trees to residents who request one! New Yorkers can get theirs here [5], Angelenos here [6]. Check with your city to find out about similar programs for your neighborhood.

Photo by questioning[lovely] [7]