The term "solar trees" normally refers to carports covered with solar panels, a popular new thing these days, at least in California:
http://www.wired.com/science/discoveries/news/2006/12/72292
http://www.ecogeek.org/content/view/1665/
http://en.wikipedia.org/wiki/Envision_Solar
But in Vienna, it's art:
http://www.treehugger.com/files/2007/12/solar_tree_hits_the_streets_ross_lovegrove.php
http://www.wired.com/science/discoveries/news/2006/12/72292
http://www.ecogeek.org/content/view/1665/
http://en.wikipedia.org/wiki/Envision_Solar
But in Vienna, it's art:
http://www.treehugger.com/files/2007/12/solar_tree_hits_the_streets_ross_lovegrove.php
