Written by Richard Thompson
Trees are living artwork that decorate the common area. They are beautiful and soothe the soul but are constantly changing. Like all living things, they need care and attention.
Trees are pruned to produce an effect in the landscape – that’s the “art” side of pruning. Understanding and being able the tree’s growth and health response to pruning is the “science” side.
The American National Standards Institute’s criteria for tree pruning called “ANSI A300” was adopted in 1995. It should be followed in all pruning situations and geographic areas.
Making Cuts: Branches should be removed with thinning cuts. A thinning cut either removes a branch at its point of origin or shortens it back to a lateral branch that is large enough to assume the terminal role.
Branches should not be removed with heading or topping cuts. A heading cut is when a currently growing or one-year-old shoot is cut back to a bud, or when a larger limb is cut back to a stub or a lateral that is not big enough to assume the terminal role. Heading should not be used in shade and ornamental tree pruning, since it forces the growth of sprouts that are weakly attached to the parent stem. Drastic heading can kill the tree outright.
Branch Size: A minimum or maximum diameter size of branches to be removed should be specified in all pruning operations. This establishes how much pruning is to be done.
Pruning Objectives: Pruning objectives should be established prior to beginning any pruning operation. A300 provides two basic objectives:
Hazard Reduction Pruning: This is recommended when the primary objective is to reduce the danger to a specific target caused by visibly defined hazards in a tree. For example, hazard reduction pruning may be the primary objective if a tree had many dead limbs over a park bench.
Maintenance Pruning: This is recommended when the primary objective is to maintain or improve tree health and structure, and includes hazard-reduction pruning. An example here might be to perform a maintenance pruning operation on a front yard tree.
- Crown Cleaning consists of the selective removal of one or more of the following items: dead, dying, or diseased branches, weak branches and watersprouts.
- Crown Thinning is the selective removal of branches to increase light penetration, air movement, and reduce weight.
- Crown raising consists of the removal of the lower branches of a tree to provide clearance.
- Crown reduction, also called crown shaping, decreases the height and/or spread of a tree. Consideration should be given to the ability of a species to sustain this type of pruning.
- Vista pruning is selective thinning of framework limbs or specific areas of the crown to allow a view of an object from a predetermined point.
- Crown restoration pruning should improve the structure, form and appearance of trees which have been severely headed, vandalized, or storm damaged.
When you contract a company for tree care, you should obtain a written commitment that, “All pruning shall be done in accordance with the ANSI A300 standard for tree pruning.” This means:
- Proper cuts will be made.
- Spikes won’t be used to climb. Spikes are injurious to the living tree and should only be used in emergency situations or when the tree has very thick bark.
- Not more than 1/4 of the foliage of the canopy or individual limbs should be removed in any one season.
- When pruning is completed, at least ½ of the foliage should remain evenly distributed in the lower 2/3 of the canopy.
Trees are one of a homeowner association’s biggest assets and need to be treated with respect and care. Use only a trained arborist and budget in your reserve plan for recommended pruning.