« Useless, unrestrained, big, generous. These are the traits of the Ailanthus(樗 – Ailanthus altissima) that Zhuangzi evoked to illustrate his Tao philosophy. Today, these same traits are reproached to specimens of this species, which thrives in temperate regions on every continent. Simon Boudvin followed the development of a population of Ailanthus during ten years in an area to the east of Paris, between the communes of Bagnolet and Montreuil. Here, he shares an extract from his photographic survey, complemented by an account of the history, travels, integration and rejection of ailanthus in our sciences and cultures. This site-specific monograph questions our ability to welcome the emergence of a spontaneous form of life, and to relax our exclusive control over the space of our cities. »