Fine pruning is recommended for premium quality work with an emphasis on aesthetic considerations in addition to structural integrity. Fine pruning shall consist of the removal of dead, dying, diseased, decayed, interfering, objectionable, obstructing, and weak branches, as well as selective thinning to lessen wind resistance.
The removal of such described branches is to include those on the main trunk as well as those inside the leaf area. An occasional undesirable branch up to one-half inch (1.25cm) in diameter, as described above, may remain within the main leaf area to its full length when it is not practical to remove it.
All cuts shall be made as close as possible to the trunk or parent limb, without cutting into the branch collar or leaving a protruding stub. Bark at the edge of all pruning cuts should remain firmly attached.
All branches too large to support with one hand shall be precut to avoid splitting or tearing of the bark. Where necessary, ropes or other equipment should be used to lower large branches or stubs to the ground.
Treatment of cuts and wounds with wound dressing or paints has not been shown to be effective in preventing or reducing decay, and is not generally recommended for that reason.
Wound dressing over infected wood may stimulate the decay process. If wounds are painted for cosmetic or other reasons, then materials non-toxic to the cambium layer of meristematic tissue must be used. Care must be taken to apply a thin coating of the material only to the exposed wood.
Old injuries are to be inspected. Those not closing properly and where the callus growth is not already completely established should be bark traced if the bark appears loose or damaged. Such tracing shall not penetrate the xylem (sapwood) and margins shall be kept rounded.
Equipment that will damage the bark and cambium layer should not be used on or in the tree. For example the use of climbing spurs (hooks, irons) is not an acceptable work practice for pruning operations on live trees. Sharp tools shall be used so that clean cuts will be made at all times.
All cut limbs shall be removed from the crown upon completion of the pruning.
Trees susceptible to serious infectious diseases should not be pruned at the time of year during which the pathogens causing the disease or the insect vectors are most active.
Similarly, if pruning wounds may attract harmful insects, pruning should be timed so as to avoid insect infestation.
Remove the weaker or less desirable of crossed or rubbing branches. Such removal, if possible, should not leave large open spaces in the general outline of the tree.
Where practical, all visible girdling roots shall be treated as follows:
Cut root at either end, or:
Sever root in center with a chisel and allow growing tree to push root away.
Remove section of root.
The presence of any disease condition, fungus fruit bodies, decayed trunk or branches, split crotches, or branches, cracks, or other structural weakness shall be reported in writing to a supervisor and/or the owner, and corrective measures recommended.
