a recent installation by dutch artist and designer simon heijdens nature is become rare. even the trees we see in our cities are planned and managed. projected onto a façade in the centre of berlin (checkpoint charlie), the ‘tree’ is an intervention that questions the role of nature in the built environment. sensors pick up the movement of passers by and changes in the weather. virtual branches sway to real wind. digital leaves fall to the sounds of the city street. throughout the installation the tree becomes barer and barer, creating an ongoing image of human activity.