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MASTER The Art and Science of Tree Pruning09-01-04 | News



MASTER
The Art and Science of Tree Pruning

By Mario Vaden,
certified arborist/certified landscape technician
and owner of M. D. Vaden Trees & Landscapes






Don?EUR??,,????'???t make your pruning cuts like this. The cut on the right side of this tree was made about 1/2-inch too far outside the branch collar. The cut on the left is about 1/4-inch too far outside the branch collar. Without damaging the collar, it?EUR??,,????'???s important to make the cut close, so the tree can start to enclose the wound and seal it with new tissue as soon as possible.


Landscape contractor?EUR??,,????'???s opinions vary on the difficulty in adding tree care to their list of services, but arborist Mario Vaden (a landscape contractor) thinks adding tree services will not only add services?EUR??,,????'??+and revenue?EUR??,,????'??+to your business, it will make you a better landscape contractor.






To remove larger branches, make two cuts?EUR??,,????'??+an undercut and an ?EUR??,,????'??overcut.?EUR??,,????'?? Make the cuts almost together, at about eight inches away from the trunk. Follow with cut number three near the trunk to remove the remaining stub.







How could a successful landscape contractor design a planting blueprint without understanding the effect and needs of trees? They couldn?EUR??,,????'???t. Trees and turf are inseparable. If you want to be good at caring for either one, you better know both. So, do your crews already have the knowledge to spring into tree services? Ask yourself, ?EUR??,,????'??When my crews go out to remove a tree in summer, do they consider how the now exposed understory of hydrangeas and shrubs might get sunburned??EUR??,,????'?? If they don?EUR??,,????'???t, then they probably need to give themselves a jump-start by taking a course in arboriculture training where they would learn that winter might be a better season for the tree removal.

The Three Cut Removal Method

To remove larger branches, make two cuts?EUR??,,????'???an undercut and an ?EUR??,,????'??overcut.?EUR??,,????'?? Make the cuts almost together, at about eight inches away from the trunk. Now your ready to remove the remaining stub with a third cut closer to the branch collar.

Suppose that the branch you want to cut is small and you have good hand strength?EUR??,,????'???is it acceptable to cut the entire branch with a single cut near the trunk? Sure, as long as you can do it without tearing the bark. That?EUR??,,????'???s bending the rules without breaking them.

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(1)
A pruning cut must be made just outside the branch collar (1), without damaging the collar, a position that can sometimes be hard to locate. You can easily identify the branch collar on a cedar tree (2) by the ridges, wrinkles and a slight bulge that circle the area where the branch meets the trunk.





(2)


How do you know what cuts are good for specific conditions? Experiment?EUR??,,????'???practice on trees that need removal. You may also find that if you put controlled, slight downward pressure on a limb, the wood fibers will cut much easier. This is also a ?EUR??,,????'??bending the rules?EUR??,,????'?? technique and should be practiced on trees that are slated for removal. These expendable trees are one of the best training resources available?EUR??,,????'???don?EUR??,,????'???t waste them.

Working the Seasons

In a perfect world, landscape contractors would be able to prune the right tree on the right day, but with most contractor?EUR??,,????'???s hectic landscape installation and maintenance schedules, that idealism is hardly attainable.






(3)
Avoid the girdling damage (3) that results from bracing with chains or wires that wrap around tree trunks. A better method of bracing is to screw a galvanized steel eye (4) into the tree and secure with one-sixteenth inch aircraft, or similar grade, cable. Use a small crimping tool (5) to compress ferrules that hold cables in place. This works great for bracing large shrubs and small trees that may have inherent weaknesses that can?EUR??,,????'???t be removed by pruning. Without this procedure, many weak trees can eventually split down the middle as easily as peeling a banana. The crimping tools are about $50 at local hardware stores. Larger trees need larger cables, as well as greater arborist skills.





(4)





(5)


One big pruning restriction (a rule that you don?EUR??,,????'???t want to bend) involves removing top growth, as with fruit trees and skilled crown reduction. Don?EUR??,,????'???t prune much off the top of trees prior to summer heat?EUR??,,????'???it will open the door to sunburned bark. Save your isolated top-pruning needs for the cool seasons.






Codominant leaders are not branches but large stems that developed upward from a union with the main trunk. These leaders often lack a branch collar. Instead, they can form bark ridges in-between called ?EUR??,,????'??excluded bark?EUR??,,????'?? or also, an enfolding called ?EUR??,,????'??included bark.?EUR??,,????'?? Sometimes, as in this photo, a bark ridge is not apparent. In that case, stay away from the tissue in the center of the two leaders, where that kind of union should exist, although not obvious. This photo displays the proper way to remove this codominant leader.





Tying a rope to brace a tree can be a deadly error. Once a rope embeds, as on this deodar cedar, the tree is finished. Using rope to temporarily brace a tree is not a good practice, because the rope can become hidden or forgotten, especially if oversight of the tree changes to another person. Bracing should be performed on a need basis only, since trees develop better trunks if bracing is not required during planting.


Twelve Hazard Tree Signs

Before pruning, always look over the entire tree to locate any potential hazards.

  1. Multiple Leaders

    2. Many trees have multiple leaders, like trunks. Often the leaders form weak ?EUR??,,????'??V?EUR??,,????'?? shaped unions where they join the trunk. These could allow the tree to split.

  2. Leaning Trunk

    3. Trees that lean from a normal vertical position may be slowly progressing into a greater lean over time. Gaps in the soil indicate that the root system is pulling loose as well as detection of changes of the trunk?EUR??,,????'???s angle.

  3. Weak Branches and Limbs

    4. As with major leader unions, branches attached by ?EUR??,,????'??V?EUR??,,????'?? shape unions can be weak.

  4. Hollow Cavities

    5. Inspect trees for peeling bark, hollow cavities and conks or mushroom growth on bark. Fungus is a sign of decay.

  5. Tree History

    6. Before pruning, investigate the history of the tree. Has the tree been topped? Has the grade changed? Have roots been damaged?EUR??,,????'???possibly from trenching or concrete work? Detected problems may require removing excess fill soil, corrective pruningor possible removal.

  6. Cracked Trunks

    7. Cracks in tree bark can be natural. Usually, cracks in the underlying wood aren?EUR??,,????'???t a good sign. Cracks may be a result of wind and ice damage. Tiny cracks may close over on their own. Large cracks may require that the tree be cabled or removed. Medium cracks may necessitate that the tree be inspected annually or biannually.

  7. Hanging Branches

    8. Look for broken or hanging branches that are damaged and are hanging by a thread (?EUR??,,????'??hangers?EUR??,,????'??). Be sure to remove these branches?EUR??,,????'???they can fall and injure a trimmer who is not prepared or anyone else that walks or plays beneath the tree.

  8. Deadwood

    9. Deadwood includes any dead branches that are attached properly or improperly that will eventually come loose. These can fall during any season and pose a safety threat.

  9. Suspended Limbs

    10. Sometimes limbs and tree tops break and only fall a few feet before getting caught in the tree. Make sure the leader is intact. If tops or branches have broken loose and are ?EUR??,,????'??hung-up?EUR??,,????'?? in a tree, remove the ones that can be reached. A hard hat is proper gear. If the hazard is too high or you lack the ability and training, contract with a trained arborist for the removal.

  10. Starved, Stunted Trunks

    11. Tree bark will engulf wire or rope left on a tree. The trunk above that damage will often become bigger and heavier, but the lower supporting trunk can stay small, slowly starving and getting weaker. If the wire or rope cannot be extracted, the tree may need to be removed.

  11. Tree Near Power Lines

    12. Trees can conduct electricity. On trees near power lines, look for tree branches with scorched tops?EUR??,,????'???they may have made contact. Trees near power lines require additional training and should not be pruned or moved by anyone other than a qualified person.

  12. Trees Being Pruned

    13. Anytime a tree is being pruned?EUR??,,????'???whether by an amateur or a professional?EUR??,,????'???consider it a hazard. Tree workers, even the most safe, don?EUR??,,????'???t always have a clear view of what is below them. Spotters are essential in many tree care operations.

    Copyright by M. D. Vaden 2004



    When to Prune








    According to researchers from the Virginia Cooperative Extension, January and February are the best months to prune alder and crape myrtle trees in their area while beech trees perform best if pruned in July, August and September. Flowering trees like dogwood, crabapple, magnolia and flowering cherry should be pruned in June or July, before flower buds have set. In Washington, the best time to prune forest trees is generally in the fall during their dormant season, but sparks from saws are better arrested in the wet season. So, how do you know when to prune? Many local universities offer tree resources including detailed calendars with recommended pruning months identified by tree type.



    University Tree Resources

    University of California?EUR??,,????'???Tree selection, planting, propagation, irrigation, care and diseases ?EUR??,,????'??? www.dnr.wa.gov/htdocs/rp/stewardship/bfs/WESTERN/introduction.html

    University of California Cooperative Extension, El Dorado County?EUR??,,????'???Free master gardener classes on pruning, planting and propagation ?EUR??,,????'??? calendar.ucanr.org/calmain.cfm?freshen=yes&group=616

    Oregon State University Extension Service?EUR??,,????'???Training and Pruning Your Home Orchard, a 14-page guide that illustrates the basic principles of training and pruning apple, pear, sweet and sour cherries, peach, prune, plum, walnut, filbert and apricot trees.
    Order online at or call 800-561-6719. Tree identification ?EUR??,,????'??? oregonstate.edu/trees

    Virginia Cooperative Extension?EUR??,,????'???Virginia pruning calendar and tree selection ?EUR??,,????'??? www.ext.vt.edu/pubs/nursery/430-460/430-460.html

    Virginia Tech?EUR??,,????'???Tree and woody plant identification ?EUR??,,????'??? www.cnr.vt.edu/dendro


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