Pruning Scar(s) Tree pruning is an old practice for regulating tree size and the shape of a tree's crown and for removing dead or damaged branches. It is an essential part of tree maintenance in an urban environment. Excessive pruning and flush cuts (a poor pruning practice in which both the branch and stem tissue are removed) can weaken the defense system of a tree (Shigo, 1990). Any process of removing dead or live branches and limbs will leave a scar. Proper pruning scars (Figure 1) will form circular wound-wood around the cut and old pruning scars may eventually heal over leaving a distinct knob. When pruning cuts are made improperly, wound-wood may form only to the sides of the wound, or partly about the wound. These scars may also form a point of entry for wood rotting organisms. Figure 1 Tree ProblemsBasal or Trunk Scars