A tree’s roots are its foundation, and its lifeline. While they're best left alone, there are a few reasons to cut or remove them—for the tree’s health, to protect a building or structure, or for aesthetic and safety reasons. In these cases, it can be okay to take out a portion of the root system, however, it must be done delicately, and with care. Here’s how to remove a tree root without hurting the tree.
Overview of Tree Root Systems
Generally speaking, about a quarter of a tree’s overall structure is found in its roots. Structural roots help keep the tree sturdy and in place, while feeder roots go searching for water and food.
Structural roots are larger, and most times run deep and directly below the tree, like a large taproot. Feeder roots are more commonly found just below the surface, anywhere from a few inches to around two feet. Of course, there are anomalies where you find a root above ground, or possibly going deeper in its search for nutrients and moisture.
Do Your Research First
Tree roots have a mind of their own, and can get into places that they shouldn't. Each tree will be a little different when it comes to their root systems, so the first thing to do is research the the tree that you are dealing with. Some will have shallower surface roots, or will react more severely to being tampered with.
You’ll need to determine if cutting or removing roots is overall the best idea in the long run, especially when it comes to the size of the tree, and its health. If it hasn't reached maturity, and already roots are a problem, removing the whole tree may be a better solution, as they will continue to grow larger. You'll have to weigh the pros and cons of the work that needs to be done, and whether removing the root will stop the problem in the first place.
Roots Are Impairing Structures
Tree roots can get into or obstruct water lines and pipes, or in even rarer cases, may disrupt a home’s foundation, but these are usually more a problem with bad construction, old pipes, and loose soil. Nonetheless, these are serious situations in which the root(s) responsible must be removed in order to save the structure in question.
This is where you must determine the right course of action: if the root you need to remove is too close to the main trunk of the tree, you’ll risk severely injuring, or killing it. In this case you would want to consider removing the whole tree instead. If the root is far enough away then you can prune or remove it safely, and place a barrier to stop it from growing into the structure again.
Roots are Above Ground
Some exposed tree roots look neat as they snake along the landscape, however if this is happening in your lawn or close to your property you may have an aesthetic, or a safety reason to remove them. Again, consider how far they are from the main trunk and whether you can cut them without injuring the tree.
Any kind of root removal is going to affect the tree's health, even if it's minor, so ask yourself if there are ways to work around, or live with the exposed root. Adding soil and re-seeding is not always the best thing for the tree, either, as it can suffocate the root, and it will likely continue to grow upward in time anyway. Adding a mulched or compost area over top of an exposed root can be a healthier alternative, as it provides oxygen and organic material.
Roots are Lifting Pavement
This is another situation in which you must weight the pros and cons of cutting parts or sections of roots that are causing pavement or concrete to break. Small areas can be trimmed, even tops of exposed roots could be shaved without too much trauma, however, the root will likely continue to grow back. A barrier can be installed at the cut point to prevent roots from lifting concrete areas again.
This can cause major uncertainty to the health of the tree and its structure, especially if a large root is removed. Without proper support a tree has a better chance at being blown over in a storm, or falling. Remember, any kind of tampering with tree roots will potentially harm the tree in some way, so consider whether you can construct around them.
If construction, environmental factors, or high impact has somehow exposed and damaged any tree roots the best thing to do is to cut the damaged area cleanly with a sharp saw or shears, as this will help the root heal, and prevent disease. Similar to pruning branches – the cleaner the cut, the less damage to the tree.
You don't want to leave the roots exposed, either, so filling eroded land back in, or pushing roots into the ground will help, as well. Extra water should be provided. Sometimes a tree will develop girdling roots in which they wind around the base of the trunk. In most cases, it may be better to leave them, instead of removing or cutting the roots.
Root Cutting and Removal Basics
If you do end up deciding to remove a root, there are essential rules to follow that will give the tree its best chance at surviving the trauma.
Keep Two Thirds or More
Never remove more than a quarter of a tree’s root system, especially not all in one place as this can cause the tree to lean and possibly fall over.
Avoid the Trunk
You shouldn’t remove roots that are close to the base and trunk of the tree, as this causes the most shock to its system: multiple the tree's diameter by at least three in order to gauge the safe distance. For example, if the tree is two feet round, you can cut roots that are six feet away, at minimum.
Let the Plant Rest
Give the tree at least a couple of years to recover before removing or cutting roots again.
Prune During Dormancy
Like pruning branches, make sure cuts are clean and done during a time that the tree is not budding or in active growing season. Late fall and early spring are the best times to do any work, generally speaking.
Only Trim Roots as a Last Resort
Roots are best left in tact, and should only be pruned or removed if absolutely necessary. If a cut is going to be too close to the trunk of the tree, you risk killing the tree, and may want to either forego the work, or take the tree down altogether in a safe way.
Making the right decision to remove roots, leave them alone, or take down the tree is not something you should take lightly. Talk to a local arborist before any major work gets underway, and follow these rules to remove roots without hurting the tree.