Pollarding machine - GIF

[bricolage]

The second and third photograph shows pollarded trees, probably willow. The thin branches are harvested annually or bi-annually, depending on the thickness required and then are used for willow baskets. If the bark is left on for a while, you end up with buff colored canes, if taken off they are white. To pollard a tree for this use the top is cut off of a young tree, which then sprouts at that cut, and each year sprouts again from the same area so making that bulge at the top of the trunk.

The first photograph is more likely (I think) showing a machine to remove side shoots when young and small. The trunk then years later when harvested will only have small knots toward the center of the tree instead of large knots. This would make for more valuable, "mostly" knot free boards.