The documentary film 'Concrete Green Island' explores the trees that have been with people around the apartment complex through the redevelopment process of the Gaepo Public Housing Apartment in Seoul. Director Lee Seong-min records the appearance of the trees through the camera for 7 years and explores what meaning they have in the city. Although most of the trees will be cut down due to redevelopment, some will be preserved by being included in the park. The film raises environmental issues arising from the redevelopment process, such as the relationship between nature and the city, and urges people to pay attention to the trees in front of their homes. 'Concrete Green Island' will be released on August 19th.