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ARBORICULTURE: PRUNING
  MG Manual Reference
Ch. 13, pp. 19 - 23

First Develop a Plan

1. What is the reason for pruning? To stimulate fruit production? To remove diseased or damaged wood? To remove a limb that is in danger of falling and injuring someone? For aesthetic reasons? To develop strong scaffold branches? Or to reduce the size?
NEVER PRUNE WITHOUT A PURPOSE IN MIND.
2. What type of tree is to be pruned? A young tree? A deciduous fruit tree? A broad-leaved evergreen? Or a conifer? The type of tree will determine when and how to prune.
Some Pruning Basics

1. Use your cuts to shape the growth of the tree.
2. Do not remove side branches of young tress in an attempt to force the canopy higher. This results in a weaker trunk and reduces growth. Remove these branches slowly over a period of five to seven years.
3. Always cut back to a branch that is at least 1/3 the size of the branch you are cutting off. The energy of the limb that is removed will now be channeled into the branch to which you cut back. Be sure that you cut to a branch that follows the original line of the limb.
4. Do not remove more than 15% of the foliage at one time. Do not remove more than 30% in one season.

A) double leader
B) interfering branch
C) heading back side branch
D) sucker
E) broken branch
F) water sprout
5. If the branch to be cut is larger than 1 inch in diameter it is necessary to remove it with three cuts. The first two cuts are used to remove the weight from the limb and thus take the stress off of the final cut. The first cut is an undercut made one to two feet from the branch collar, going in 1/3 of the diameter of the branch or until the blade begins to bind. The second cut is made from the top, all the way through the limb, 1" past the first cut. The undercut made in the first cut ensures that when the second cut is made the bark does not tear down the remaining branch. The third and final cut is made from the bottom up, just beyond the branch collar.
6. Do NOT cut the branch off flush with the trunk. The meristematic tissue, which will grow to seal the wound, is in the branch bark collar. Removing this tissue impedes the "healing" process.
7. NEVER "top" or "stub" a tree. This dramatically shortens the life span of the tree. It will not result in a smaller tree, it merely exhausts the tree as it expends tremendous energy to regain its original size to replace the missing leaf area. Rather than making a tree safer, topping actually makes a tree hazardous. Topping opens the tree to invasion by rotting organisms, it starves the tree by removing the leaves that produce food, it results in weakly attached limbs formed on sucker or shoot regrowth, and it causes the tree to become top heavy due to thick regrowth which increases the likelihood that the tree will be blown over.
8. Do NOT seal the wound; this interferes with the healing process.
Pruning StepsTop

1. Remove diseased, damaged, and dead limbs.
2. Remove crossing limbs and limbs that head back into the center of the tree. With a young tree, select a leader (the tallest, most vertically growing stem).
3. Examine the remaining branches for vertical (spacing up and down the trunk) and radial (spacing around the trunk) spread.
4. Select scaffold branches that are evenly distributed and have wide branch angles.
Deciduous Shrubs
1. Thin out by cutting the oldest and tallest branches back to their points of origin or to a lateral side branch.
2. Prune immediately after blooming in order to minimize disruption of the next year's blooms.
3. The goal is a more open plant, not excessive top growth. The plant can be maintained with a natural appearance at a given height and width for years by thinning out.
Pruning Deciduous Hedges
1. Select young trees or shrubs, multiple-stemmed, with small foliage that grow quickly.
2. Prune back to 6 to 8 inches at planting time to promote branching.
3. Late in the first season, prune off 1/2 the new growth.
4. Second year, prune off half of the new growth.
5. Third year, begin to shape to a slightly rounded or pointed top (not flat) with sides slanting to a wide base.
6. Maintain the top narrower than the bottom to insure that sunlight reaches the lower leaves.
Evergreen Hedge
1. Do not prune back as severely as deciduous hedge.
2. Trim lightly after a year or two.
Palms
Hire a professional to prune tall palm trees.
Storm-Damaged TreesTop

Treating storm-damaged trees requires wise decisions and prompt action if maximum repair is to be achieved. Consider hiring a professional certified arborist. Repairs come in two stages: first aid for immediate attention and follow-up work to be distributed over a period of several months to several years.
In deciding what action to take, you must consider the following factors:
Severity of damage. If over 30 to 50 percent of the main branches or trunk are severely split, broken, or mutilated, it may be advisable to remove the tree.
Desirability of species. This may provide a good excuse to replace a tree that you did not have the heart to remove.
Location. If too close to power lines, buildings, or other structures, the tree may need to be removed.
Soundness. Extremely old trees of low vigor might not be able to recover.
Special values. Rarity of species or variety; sentimental or historical value.
Purpose of tree. Does it serve a true landscaping purpose or value? If you decide to repair the tree, remove only the branches necessary for immediate repair. Removing too much wood in one season can result in sun scald, weak branching habits, and soft sucker growth. Follow standard pruning guidelines regarding where and how to make cuts. Promptly remove from the premises all debris such as broken branches and prunings to help eliminate breeding grounds for insects and diseases. Gradually prune and reshape the tree for balance and general appearance over a period of three to five years.
Mower and Weed Wacker WoundsTop

Injury and infection started by lawn mower wounds can often be the most serious threat to tree health on golf courses, parks, and home lawns. Lawn mowers cause the most severe injury during periods when tree bark is most likely to slip, in early spring during leaf emergence and in early fall during leaf drop. If the bark slips, a large wound is produced from even minor injuries.
Most tree injuries occur when mower operators attempt to trim close to tree trunks with a power mower. This can be prevented by removing turf around trees and replacing with 3-4 inches of organic mulch or by hand trimming. Care must also be used to avoid harming trees with filament line weed trimming machines. They can do a great deal of damage to bark, particularly on young trees. The usual site of injury is the root buttress, since it flares out from the trunk and gets in the path of the mower. However, injury is common anywhere from the roots to several feet above the ground. Although large wounds are most serious, repeated small wounds can also add up to trouble.


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