Removal Cuts: Stubs and Cavities

Removal cuts are pruning cuts that take off a branch at the trunk or on a major branch.  These cuts are essential to shaping a strong upright street tree, when they are done on young trees.  Making them at the right time in the life of a tree and without damaging main woody structures requires skill, practice and judgment.  The earlier and the smaller the diameter of a removal cut, the more likely that a tree can close the wound.  One rule of thumb is that branches should always be kept to a diameter less than 1/2 that of the trunk diameter.  This is done by making other pruning cuts that control growth of the branches themselves.  It is also important that pruning cuts be done in a way to keep the "branch collar" intact, because the branch collar is the tree's tissue that forms a wound collar to close the over and heal the cut.  FLUSH cuts always cut into the branch collar and damage the living bark of the trunk itself.  Flush cuts often lead to long fissures along the trunk or major branches.

When a large branch is cut away it often leaves a stub insert in the trunk.  When the tree can’t close the wound, the cut site and the stub become a source of rot into the main structure.  You can find these problems on many trees, especially on maples.

 It is now recommended that trees have scheduled structural pruning for the first 25 years of growth (yes, 25 years).  Initially, on young trees, pruning is yearly, and then every several years thereafter.  One of the reasons that so many of our trees are in poor condition is that many removal cuts were made late, well after the tree needed them.  Therefore, we see  trees with rotting stubs and unclosed rotting cavities all over the Park.  Our trees were also allowed low branches with weak structures that broke easily in storms. 

A well healed cut of a small branch relative to trunk diameter

Removal cuts that left stubs to rot and deep cavities developed.

Stub Up Close    A Cavity & Open Wound Rim                          
A huge low lying stub from a co-dominant branch (above)