What is an Air Knife and what is it used for?
How do Stem-girdling Roots kill trees?
How can we correct problems caused by planting too deeply and over mulching?
Watch a video of an Air Knife demonstration and learn about root flares, stem-girdling roots, and soil aeration.Afterward, follow the next three links to three other videos, which go into greater detail about root flares, planting too deeply, and the “repair” process. Organic Air would like to give special thanks to Tyson Woods, of Moore Tree Care, in Dallas, TX, for allowing us to refer to their outstanding presentations.
| http://www.youtube.com/watch?v=liD7BfPRseY |
| http://www.youtube.com/watch?v=65HwbclhEMA |
| http://www.youtube.com/watch?v=nxkVebO9czk&NR=1 |
A Solution for Compacted Soils and Invisible Root ProblemsThe Air Knife uses compressed air to inject oxygen directly into the soil, giving plant roots a much-needed breath. It is also used to excavate soil from around trunks of trees or to find troubled roots that may need to be removed, such as those growing into a home’s foundation.
Have you ever noticed a branch on a tree turning to its fall colors earlier than the rest of the tree? Or how about an entire tree turning earlier than others of its kind? This is usually a sign that the tree is, for some reason, unable to transport nutrients from the soil up to the leaves. Often, it’s an indication that the roots are under stress from soil compaction or poor drainage, and are starving for oxygen. As they die back, they are less able to pull up the minerals the tree needs for proper function. Another cause for this type of tree decline is stem-girdling roots. The Air Knife can be used to excavate soil from around the trunk to expose the problem and remove the destructive roots, without harming other important roots, or cutting into the main trunk.
The roots shown at right, wrapped around this trunk, are called “stem-girdling roots” and are much more of a common problem than people realize. They are the result of planting a tree too deeply, or piling too much mulch around the trunk. As these roots continue to grow, and the trunk gets larger, the girdling roots squeeze like a noose, cutting off the flow of nutrients, and eventually, kill the tree.
Over-Mulching:
“Too much of a good thing”An example of mulch piled too high against the trunk of a tree. With no visible “root flare”, the end result could be called ”Telephone Pole Syndrome”
Here is an extreme example of excessive mulching. Unfortunately, however, these “Mulch Volcanos” are not an uncommon sight. It’s not unusual for trees to die during their first year after planting, when mulched this way. If the tree survives past the first year, and the practice continues, over time, stem-girdling roots develop and, eventually, kill the tree.Here’s a link to an incredible website that expands on these ideas:
http://www.tlcfortrees.info/mulching_staking.htm
More links to web sites warning of the dangers of planting too deeply:
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Correct Tree Planting: “The Perils of Planting Trees Too Deeply” |
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Ohio Department of Natural Resources feature article, ODNR Division of Forestry |
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Deep Roots of Landscape Trees |
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Benefits of Root Collar Excavation, and problems associated with deep planting, Article from Morton Arboretum, Chicago
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