How does tree of heaven care for us?

Known as the tree of heaven, Ailanthus is written about in the oldest Chinese dictionary. They came to the United States in 1874 at time when landscape designers were entranced with Asian culture, but by the turn of the century when it became clear how quickly they spread and how the ailanthone in their bark and roots inhibits the growth of other species, they began to be labelled a foreigner, an invader, linking plants to borders and immigration policies. But they are incredibly tough; they can provide erosion control along the banks of highways, they can provide shade in urban areas lacking much tree canopy, they are not particularly affected by pollution, and they can grow amazingly quickly.  They are also known as the stink tree because of the smell, of their flowers which humans find noxious.  

As a phytoacummulator, they can absorb pollutants such as sulphur and mercury, which makes them a valuable ally in reducing toxins.  They flourish in ruderal worlds usually considered hostile of life: along roads and railways, in sidewalk cement cracks, in abandoned urban lots. As our climate changes and our ecosystems become hotter or drier or simply different, they will be able to thrive when other trees will not.  They have become a powerful symbol for beings that can flourish in what seem like impossible situations and of immigrants being able to thrive in difficult circumstances.   Their story is one of complex ecologies with multiple strands that reach into human sensory experience, geopolitical imagination, colonialism, urban decay and revitalization, and so much more.