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Sample Pruning Specifications for Young Trees


C. Way Hoyt, Tree Trimmers and Assoc. Inc., Oakland Park, FL;
Edward F. Gilman, Professor, Environmental Horticulture Department, University of Florida

GENERAL

The primary reasons we prune trees are to improve trunk and branch structure, to remove or shorten low limbs for under-clearance, to thin the canopy to allow better air flow, and to maintain tree health.  Although we are concerned with aesthetics, the appearance of the trees will be secondary to health and structural concerns.  The single greatest structural concern is the large number of codominant trunks or main leaders.

The specified pruning may require the removal of up to thirty percent of the foliage in many instances.  Under no circumstances shall more than forty percent of the foliage from an individual tree be removed.

Other than when shortening limbs for clearance over roadways or sidewalks, removal of live limbs smaller than one inch in diameter on the interior of the canopy will not be required. In fact, this is discouraged and is considered unnecessary. Removal of dead limbs or stubs one inch in diameter or larger will be required.

All pruning is to be done within the scope of the approved techniques as described in ANSI A300-1995.  Work is to be done by workers trained in compliance with ANSI Z 133.1 safety regulations, as required by OSHA.
 

CODOMINANT LEADERS AND STEMS

Due to the recognized potential hazards associated with codominant leaders, the subordination (shortening using a drop-crotch cut) or removal of one side of a codominant leader is the primary objective.  Branches, trunks, or leaders not considered the main leader, two inches (note: use your own number here) diameter or larger should be subordinated or removed. The main leader shall not be subordinated or removed.  Codominant leaders are considered to be two or more branches, trunks, or leaders of approximately the same size, originating in close proximity to one another.  If there is no stem considerably larger than others, subordinated all but one of them.  Where there is included bark as part of the condition, preference should be given to the removal of one side, but only if such removal will not destroy the aesthetic value of the canopy or remove more than forty percent of the foliage.

DEVELOPING MAIN BRANCHES

On trees 15 feet or taller, begin to identify some of the main limbs (called scaffold branches) on the tree that will remain on the tree permanently. Scaffold limbs should not have bark inclusions in the crotch. Ideally, these main limbs should be positioned more-or-less radially around the trunk with no scaffold branch directly above another. Scaffold branches should not be opposite one another; they should be spaced about 18 to 36 inches apart along the main trunk. This distributes the weight over a number of well positioned scaffold branches. Many trees will not grow in this manner on their own so you have to encourage this. Do this by reducing
the length of, or removing, branches between the scaffold branches. This will send a signal to the remaining  branches to grow faster and these faster growing branches will become the scaffold branches.

CROWN RAISING OR LIFTING

Branches over paved areas should be shortened or removed to allow approximately seven or eight feet (8’) of clearance for cars and delivery vans as practical.  Over landscape areas and sidewalks they should also be shortened or removed to allow eight feet (8’) for pedestrian traffic and utility use as practical.  Shortening of branches is the preferred method for attaining adequate clearance.  When pruning is completed, approximately one-half of the foliage should originate from branches on the lower two-thirds of each tree.

THINNING

Although small diameter limbs may be pruned where the contractor desires, it will not be necessary to make cuts smaller than one inch in diameter, other than where branches may be shortened to accommodate clearance beneath the canopy.

Thinning is to include the following: remove dead or broken limbs one inch in diameter or larger; if two limbs are crossing or touch each other, shorten or remove one of them; if two limbs (one inch diameter or larger) originate within twelve inches of each other on the trunk, shorten or remove one of them.  Clearance from buildings, lights, or other structures should be a minimum of three feet (3’) or as practical.  Use directional pruning where possible so future growth is directed away form buildings and lights.
 

PALMS

All large-growing palms, should be pruned to remove dead fronds, and fronds with a petiole that droops below horizontal.  Dead fronds are those with less than 50% green tissue.  Only those fronds with petioles drooping below horizontal (9:00-3:00 o’clock) should be removed.  All seedpods should also be removed including those originating among remaining fronds. When removing fronds and seedpods, care should be taken so those fronds that are to remain are not nicked or wounded.