I thought that the shoots were taking the sap away from the old poplar, but it turned out quite differently. When I was cutting them down, the old poplar was already dying. When the leaves came out, I saw (it grew from two boughs) that one bough was bare; and that same summer it dried up completely. The tree had been dying for quite awhile, and the tree knew it, so it tried to give its life to the shoots.

That was the reason why they grew so fast. I wanted to make it easier for the tree, and only killed all its children.