So the basic idea behind all is offering seedlings of trees in some urban area of Berlin, with symbolical price for each tree (say 5€). After purchase, tree would be planted together with plaque of some sort with the name of donator, and Sparkasse logo behind it all, and perhaps some inspirational text like "Danke Berlin :)"
The money collected would be then redirected for some humanitarian purpose...be it for homeless, for sick children, for animals etc.
Some ideas for long run might be careful planning of planting, and embedding the points of planting on Android app, and depicting something with points from air on your mobile phone (Sparkasse logo, special places to visit, heart...)
///no pictures or slideshows for now, sorry///