HI PU! I have an idea that might be a tad costly, or may be too unsanitary for some. But how about renting the smallest oxygen tank you can find, dress it up with brown paper (to appear as a tree trunk) and add some tree branches. Then remind people that without trees you would not have oxygen to breath. "Here, see for yourself", offering them a quick wif from the oxygen mask! I applaud your cause, and appreciate your efforts! RED CLOWN FRED -
www.clownconceptual.com