Nowadays, the tree does not hide any more the forest. Through the branches we can perceive houses, houses which grow as mushrooms, and these mushrooms don't stop growing. But every mushroom needs a tree and has to develop in accordance with him. The mushroom cannot exist without the tree, but the tree can live without mushroom. The human society is as this mushroom, it needs the tree. The tree is the witness of the evolution, but it is also its condition.