A hilly landscape makes lines of trees disappear behind nearby hills or offers a view at a tree from above. In the Netherlands the flatness of the landscape makes that impossible. But, since the whole country is manmade, the solution for this is also manmade: an open tunnel for trees. Two concrete walls about 10 meters apart run parallel to each other. The ground between these walls, level at the extremes, gently goes down towards the middle. There the tunnel is about a tree deep.

2007