An online campaign and heated comments on micro blogs saved 600 plane trees that a "green assessment" in March had said would be removed to make way for subway construction in Nanjing.

Residents found out that the crowns had been cut from some trees in Daxinggong, preparing them for removal, and they tweeted their displeasure.

A Nanjing-based environmental group, Green Stone, launched a campaign that included collecting "smiling faces" photos of people who supported protecting the trees. Hundreds of pictures - of people from all age groups and occupations, from white-collar workers to street sweepers - were posted on the micro-blog platform.