Trees are an essential and welcome component of the urban environment. The ‘lungs of the city’, urban trees are prized as much for their welcome natural appearance as they are for their powers of filtration. In this contest we’re exploring the ways in which urban planners use trees to break up the bricks and the concrete, and how we engage with trees in our urban habitats. For some inspiration, here are two examples from the master, Cartier-Bresson - Allee du Prado , and Jardins du Palais Royal