WHAT IS THE ROOT FLARE? The root flare is not a definitive line on the tree but a critical transition zone where the root tissues (root system) transitions and becomes the aerial tissue (trunk tissue). Like your neck, it is an important area.
An incredibly high percentage of trees are planted too deeply or have had their root flares covered. The high percentage is primarily attributable to current growing practices in nurseries and tree farms. Mulching, adding soil, ground covers and landscaping also contribute to this wide spread problem. Whatever the cause, a covered root flare is detrimental to the health and vigor of a tree. Some tree varieties are more tolerant of covered root flares while other varieties are highly sensitive.
Soil and moisture on the aerial tissue of a tree creates a negative condition for the vast majority of trees. In addition to the negative impact from soil and moisture on the aerial tissue, many trees have circling or girdling roots which can literally choke or restrict the vascular system of a tree. When the root flare is covered, you are unaware of the presence of girdling roots. If girdling roots are left in place, they can squeeze the life and vigor from a tree. Girdling roots will eventually lead to the weakening of a tree and make it susceptible to a whole array of pests and diseases.
ROOT FLARE WORK: THE PROCESS IN FOUR STEPS
1. EVALUATING (visually) to determine whether the root flare is covered.
The base should look like a wine glass.
Once the flare is uncovered, you can then evaluate the depth of the root flare and whether girdling roots are present.
Prior to removing the girdling roots, you should evaluate and consider the following:
a. overall health of tree
b. quantity of girdling roots
c. size and severity of restriction being caused by girdling roots
d. size and age of the tree
e. how long the tree has been planted
Taking the above factors into consideration, you begin to remove a portion or all of the girdling roots. Ideally you want to remove all girdling roots but often, in severe cases, it may be necessary to spread the removal out over some period of time.
Many trees will not show a dramatic flare but are in between and show a slight flare. Ideally a dramatic flare is the best for a healthy tree.
2. UNCOVERINGthe root flare carefully with hand tools or ideally with an “Air-spade”. You want to be very careful to not nick or damage the aerial tissue that has been covered as this tissue will be very soft and easy to damage.
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The hand tools used in removing girdling roots are hand pruners, loppers, saws, and wood chisels. Care needs to be taken to not cut or damage the underlying root flare. Depending on the severity of the girdling roots this can be a tedious and time consuming process.
Once the root flares are exposed and girdling roots are removed, a determination must be made as to how to leave the area. Often you have a sunken area around the base of the tree that can be unsightly and also prone to collecting water. Some combination of the following may be appropriate:
a. minor regrading of the area
b. significant regrading
c. grading to provide drainage or installation of a drain line
d. installation of a retaining wall that would be merely functional or aesthetically pleasing depending on its visibility
e. back filling of the area with large river rocks or some type of grating. (Installation of river rocks is our least favorite treatment as it can create future maintenance issues.)
The base should not look like a pencil or telephone pole.