Pruning Young Trees
Douglas L. Airhart & Guy Zimmerman III

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Purpose

Right Tree / Right Place

Selecting Trees

Transplanting Trees

Mulching & Staking

Summary Diagram 

Pruning Trees

Topping Hurts!

Protecting Trees

Tree Root Myths

Pine Bark Beetles

Live Christmas Trees

Glossary

List of Figures

List of Video Vignettes

Related Links

Bibliography

 

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    Pruning Young Trees- Training for Structure and Form

Pruning young trees provides the greatest benefit to train them to ensure their performance, landscape potential and safety, and to minimize maintenance costs. Unfortunately, proper training is not a standard practice in nurseries. Thus, trees may acquire structural defects that can damage property, cause personal injury or cause the tree to become a liability or to fail. Trees with failures usually need to be removed.

Training reduces structural defects: co-dominant stems, multiple branches, weak attachments and dense canopies. It lowers hazard potential, and therefore trees live longer. Trained trees will have fewer branches that are well spaced, thus needing less pruning and providing easier access for arborists as the tree matures.  

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Remove the Five Ds (damaged, deformed, diseased, dying or dead branches).

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Select a leader (see diagram (Figure 7-19)) and remove or cut back competing leaders.  Be sure to use proper pruning to protect the branch collars and branch bark ridges

National Arborist Association, Inc. (1984). Pruning Standards for Shade Trees. (slide set). Wantagh, NY. Used with permission.

 

(Figure 7-15) Proper Pruning to a Lateral Branch. 

The branch bark ridge and collar are still intact.    

    a. Follow the trunk to the top. There should be only a single stem. That 1 leader should be vigorous, well attached, and vertical. If you find more than 1 leader select the best and prune out the others. If you find a broken leader prune back to a codominant stem, vertical branch, or an upright bud. If you find a curved leader stake and tie it back to vertical or cut it back to an upright bud.

    b. In all cases, you will need follow-up pruning to remove any developing codominant stems. 

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Select and establish the lowest permanent branch (lpb) (see diagram).

    a. The tree location and use will determine its height from the ground. Street trees need 8-foot clearance over sidewalks and 14-foot clearance over streets. Parkway trees may have 6-foot clearance for branches parallel to the parkway. Park and yard trees may have lower clearance, depending on their use and mowing equipment.

    b. Select a vigorous branch, and avoid any crotches with included bark. The branch diameter should be less than of the trunk diameter. Label it for future reference!

    c. Allow smaller branches to remain as temporary branches. They provide photosynthesis for growth and development, they help shade the trunk from sunscald, they decrease vandalism, and they help control the growth of other branches to emphasize trunk growth initially.

Only so much energy is available to the tree. Lateral branches are kept in check by having to compete with the temporary branches for limited food supplies.

    d. If branches near the lpb are too large, remove them or reduce their length by 1/2  to restrict their growth.  

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Select scaffold branches (see diagram) and prune back or reduce any competing branches.

(Figure 7-16) Pruning to Improve Branch Spacing. 

Remaining branches grow in all directions from the trunk to create an even canopy.   

 

From Tree City USA Bulletin No. 1, 1997, Used with permission of The National Arbor Day Foundation.

Scaffold branches are attached above the lpb. They are selected for attachment strength, spacing, and size.

A minimum of 18 inches vertical spacing is needed for trees that will be greater than 12 inches diameter. 12 inches vertical spacing between scaffold branches will be sufficient for smaller trees.  

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Select temporary branches below the lpb. Shorten them to 2 or 3 buds and keep them cut back to make them less vigorous. (See Figure 7-11.)

In general, prune no more than 25% of the entire canopy at any one time, unless defects are present. You may need to prune only 5-10% for proper training. Vigorous trees may need more pruning to provide branch spacing. Pruning is best done during winter dormancy: after leaf fall, before bud swell.

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Purpose    Right Tree / Right Place    Selecting Trees    Transplanting Trees    Mulching & Staking    Summary Diagram     Pruning Trees    Topping Hurts!      Protecting Trees     Tree Root Myths     Pine Bark Beetles     Live Christmas Trees     Glossary     List of Figures    List of Video Vignettes    Related Links     Bibliography

 

TLCforTrees.info is maintained by: Douglas Airhart, Ph.D. Certified Arborist & Jeff Plant, Ph.D, Last Updated on: 07/11/03