Concave pruners are, in most cases, the most used of all the tools in a bonsai artists arsenal. They are designed in such a way that promotes quick healing. However, most important is the fact that they allow the pruned area to heal flush with the bark--no bumps. As the name suggests, the pruned area leaves a concave region. When the tree forms a scab or callous it tends to be raised from the normal surface of the bark. The concave depression compensates for that which is one of the reasons why it heals flush. The concave cutter also promotes faster healing because of the shape of the cut it makes which tends to be taller than it is wide. Trees heal faster from the sides rather than top to bottom. Click here for concave pruners and branch cutters.