Are There Dangers In Cutting Tree Roots?

Here’s and interesting blog post from Tip Top Arborists on the dangers of not knowing what homeowners, gardening weekend warriors and fly-by-night tree removal services do when messing with the root system of a tree.

Does the following conversation from your hubby sound familiar to you as soon as he arrives home from work? It sounds pretty accurate to me. :-)

“Honey, I am so tired of looking at those roots in our front yard! I’m going to have the neighbor’s gardener, Joe Schmo’s Tree, Landscape, Automotive Repair and Concrete Service come over and cut them all out, okay?”

Whoa there, Nellie!!

There are many reasons why one sees roots in their lawn, and it isn’t necessarily because the tree is unstable or looking for water. Before you take a hatchet to those roots you first need to know what they do, why they are there and the law of Unintentional Consequences if you were to remove them.

The Function of Roots

Roots have two (2) basic functions — structure and feeding. Structure roots are those that start in at the base, growing under the canopy of the tree. As these roots move outward, they become smaller and smaller in diameter much like the structure of the limbs you see above. Their job is to provide a stable foundation. The feeder roots are small and fibrous and their job is to feed the tree, providing nutrients and water. So, you can see the distinct difference. Most people, when seeing roots, only see the structure roots, not the whole picture.

The Pruning of Roots

Remember the homeowner Nellie that wanted to go Lizzie Borden on the roots in her front yard? She doesn’t understand what potential consequences her actions may have on her tree. Here are just a few to consider –

  • Stability

The large roots that radiate out from the trunk support the tree. Cutting ones larger than 2″ in diameter can put the tree at risk of falling over in high winds

Joshua Tree with Damaged Root System

or inclement weather.

  • Diminished Vitality

Remember that roots are the ‘mouth’ of the tree. Cutting those roots reduce the amount of nutrients and water the tree can take in. Let’s call it Lap Band surgery, but in this case you don’t want to shrink the tree……. or do you?

While younger trees have a greater ability to bounce back from root pruning, older trees have a harder time. Additionally, trees that are stressed from health or environment issues are at higher risk of mortality. Signs of stress in pre or post root pruning trees may include dead limbs in the crown, stunted growth, yellow or anemic foliage.

  • Pests and Diseases

Like the human body, trees that are in distress are easily susceptible to attack from pests and diseases. Many fungal infections will enter the cut roots, causing vascular issues that are very difficult to recover from. Stressed trees can also become Hometown Buffet for chewing/sucking insects like bores, scales and beetles.

Construction and Landscape Renovation

Adding onto the house for the out-laws? Installing a pool? Or just renovating your landscaping? These are another common area where roots have the potential to be cut and damaged. If you are installing a new irrigation system in your yard, try to incur minimal damage by installing irrigation like spokes on a wagon wheel as shown.

Remember this rule of thumb — a tree will put out a root system at least as wide as the drip line.

What do I need to know if I must prune roots in my yard?

First off, remember that root pruning should NOT be for aesthetic reasons only. If the roots are damaging walkways or foundations, that is a different issue. But remember what we’ve discussed — pruning roots can have a negative effect on the tree. In your desire to save the foundation you might have weakened the tree causing it to fall on your roof. Ouch! Reach out to your local arborist for his professional opinion.

Next, don’t cut roots larger than 2″ in diameter. The maximum one should consider removing in one procedure is 20% of above-ground roots. Again, remember the potential consequences.

Is there a better time of year to prune or remove roots? Yes. winter thru early spring is the best time, as that is when there is the least stress on the tree.

So, what do we take away from this. Yes, roots can be pruned with the knowledge of how/why they exist. They can also be pruned knowing what the potential outcome may be. If you are not sure, contact your local arborist for a consultation.

I hope you enjoyed the article on Medium and if you have any questions at all about anything to do with tree care or tree removal services feel free to contact me at my page. Thank you. Chris T.

Some current news on tree roots posted in this article from the New York Times. Enjoy perusing the article.

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