It’s exploiting the natural tendency of trees to create “waterspouts” through a technique called pollarding. When a tree suffers an injury it creates a bunch of

It’s exploiting the natural tendency of trees to create “waterspouts” through a technique called pollarding. When a tree suffers an injury it creates a bunch of new twigs that tend to grow straight upwards if the injury is on the upper branches. The waterspouts grow more slowly and so in this species of cedar they develop those desirable properties.