While I wish them financial success - I have to ask: what is the life expectancy of a restaurant and what is the life expectancy of a tree?  Urban trees are precious and will outlive many commercial establishments.  And while people do not come to frequent trees, their presence is still very important in making of the essense of an urban environment.  Plus it would seem to me that this cafe has plenty of street presence with its open windows without taking up more sidewalk and cutting down trees.