Why is a buried root collar so bad for a tree? It’s just dirt and mulch piled around the base of the trunk!
Trees and shrubs have different parts that have adapted to certain conditions. The roots of a plant are able to grow in the soil and soak up moisture. The trunk is not. It grows above ground where conditions are dry.
But when mulch or dirt is piled around the base of a trunk (this area is called the root collar), it stays moist thereby suffocating cells due to water saturation. This harms the cells of the trunk.
As the cells become damaged, they are not able to perform their duties, which include gas exchange and moving food through the plant, just to name a few.
Furthermore, this mound allows the tree’s roots to grow around the trunk.
As the roots encircle the trunk, the begin girdling it. The girdling action literally strangles the tree and deprives roots and canopy of necessary resources.
But the story gets worse.
As the tree declines in health, it becomes more susceptible to attack from insects, diseases, and harmful fungi, which cause further harm.
To give an analogy, a human with a weak immune system is more vulnerable to catching colds, the flu, and other sicknesses.
The solution is to excavate the root collar to ensure it stays dry.
The excavation must be done using an an air tool powered by compressed air, such as an Air Spade.
Using digging tools instead of compressed air will damage the tree’s roots and cause more harm than good.
After excavating the root collar, prune away girdling and adventitious roots.
The root pruning can be especially tricky and may need to be staged across several years.
Properly excavating a root collar is a delicate process. If you do not have experience with this procedure, we recommend hiring an experienced professional rather than attempting to do it yourself.