Three citizen-led initiatives that are helping to keep the evergreen city for nothing: tall trees, beautiful parks, beaches and wide open spaces. Over the last few years, though, the face of the city has changed thanks to concrete high-rises that tower over the trees. Piles of garbage mar its wide avenues and a lot of its greenery is facing the axe. Now citizens are fighting back. In a rare victory for greens, the members of Tree Walk, an informal group of tree lovers, and other nature enthusiasts, successfully campaigned to stop the felling of many trees at the historic.