The following information is taken from the American National Standards for pruning, ANSI A300-2001, designed to help you understand exactly what will be accomplished in a pruning operation.
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 should be established prior to beginning any pruning operation. ANSI A300-2001 provides two basic objectives.
1) Hazard Reduction Pruning
Hazard reduction pruning (HRP) 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, your estimate may read:
Objective: Tree has many dead limbs over the park bench, hazard reduction pruning is recommended.
2) Maintenance Pruning
Maintenance pruning (MP) is recommended when the primary objective is to maintain or improve tree health and structure, and include hazard reduction pruning. For example, your estimate may read:
Objective: Maintenance prune front yard tree to maintain or improve health, structure, vigor, and include hazard reduction pruning.
Hazard reduction pruning and maintenance pruning should consist of one or more of the pruning types noted below.
Crown Cleaning – Crown cleaning shall consist of the selective removal of one or more of the following items: dead, dying, or diseased branches, weak branches and sprouts (sucker growth).
Crown Thinning – Crown thinning shall consist of the selective removal of branches to increase light penetration, air movement, and reduce weight.
Crown Raising – Crown raising shall consist of the removal of the lower branches to provide clearance.
Crown Reduction – Crown reduction 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.
Renewal Pruning – Renewal Pruning is performed on multiple-stemmed shrubs by removing approximately 1/3 of the oldest and tallest stems near ground level to encourage development of new stems.
Vista 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 – Crown restoration pruning should improve the structure, form and appearance of trees, which have been severely headed (Topped), vandalized, or storm damaged.
Young Trees – Removal of select branches to aid in growth and structural development.
Note: Due to the threat of Dutch Elm Disease, to Elms, and Oak Wilt, to Oak trees, pruning of these species will only occur between October 15th and April 1st.