Roots may become weakened and/or infected, especially large trees with large roots [RT], when planted too deep[D]. ( Arrows and stars are the proper depth.)
Above the weakened root, the trunk tissues will have a reduced amount
of energy reserves and reduced growth. The likelihood of sun injury [X]
increases when the weakened root and trunk face the southwest [SW]. The
trunk may crack to form a frost crack in the bark and some wood may die
if the weakened areas are exposed to extreme temperature changes from sun
in the afternoon to a sudden decrease at night. The very important point
here is that this type of killing injury starts from the outside inward.
The other so called frost cracks start from an old wound or injury ( improper
pruning) from the inside and work their way outward.
Girdling roots can be caused by planting too deeply [A]. Girdling roots can circle the trunk or other roots. Some other known causes are: adding amendments and fertilizers to small planting "holes" [B], container trees and shrubs with spiraling roots, squeezing roots into small planting holes [B] and more that we do not understand. Some other possible causes are rapid growth and sun at the base. Pruning girdling roots on young trees is essential. On older trees the size of the wound and injury has to be considered. Leaving a one hundred-year-old girdling root might be best. Common sense and tree biology MUST be used in each individual case. There are no set rules. Girdling roots do exist in the natural forest. Seeing one tree send out a root to another tree species is not uncommon. Many girdling roots exist under the soil. I have read about how there is a concept of mass tropisms where roots will grow toward objects of high mass. Roots in the forest have engulfed large stones just as an amoeba would. There is much to learn about soil and its associates.
Diagrams from The Desk of John A. Keslick Jr.
Call us for other FACT SHEETS on pruning and other tree care information.
John A. Keslick, Jr.
Text & Graphics Copyright © 2008 Keslick & Son Modern Arboriculture
Please report web site problems, comments and words of interest, not found.