Ключевые слова: alert, bail, city environment, city life, cityscape, danger alert, daytime, falling objects, hazard awareness, hazard sign, japan, no injury, no people, outdoor, park safety, pedestrian safety, potential hazard, precaution, protective warning, public information, public safety, public warning, risk of falling debris, risk warning, safety, safety sign, street safety, tokyo, tree, tree maintenance, urban, urban park, visitor deposit, warning sign,