Key takeaways
- Root barriers redirect roots; they do not limit how large the tree grows.
- They work best planned before trouble starts, at planting or a landscape change.
- Putting one beside a mature tree means trenching through the root zone, which can hurt the tree.
- The ISA says roots commonly spread many times the width of the crown, so a short barrier is not a wall around a root system.
- Sometimes the answer is a different tree, a different path or removal.
Barriers are one of the services we offer, so we will be plain about them. They are a tool for a certain job. Whether it is the right tool depends on how close the tree is, how big it will get and what you are protecting.
What is a root barrier?
A root barrier is a panel or sheet, usually plastic or fabric-based, placed vertically in a trench between a tree and the thing you want to protect. Roots meet it and turn, usually downward or along the panel. Battle Born lists root barriers as a service, and a certified arborist assesses the site before the work.
Why is it hard to say whether root barriers work?
Roots do not stop at the edge of the panel. The International Society of Arboriculture says roots commonly spread many times the breadth of the crown and can extend farther than the tree is tall. A barrier only changes the path of the roots that reach it. Roots that go under it, or around its ends, continue.
That means barrier performance depends on installation details: how deep, how long, how close to the structure and how it is joined. Those are site decisions, and we do not make blanket promises about them.
The case for installing early
The most reliable use is at the moment of planting or construction, when there are no big roots to cut. University of Nevada, Reno Extension says to plan for mature size, since roots can damage nearby sidewalks and structures, and to choose a site that has room. A barrier adds a margin where the site is tight, such as a narrow planting strip beside a walk.
The case against trenching an old tree
Digging a trench next to a mature tree cuts roots, and those roots hold the tree up and supply water. The ISA warns that excavation near trees can damage roots and harm or even kill the tree. For a large, old tree beside a slab, the arborist's first question is whether the tree can tolerate the trench at all, and where it can be cut with the least harm.
Sometimes the honest recommendation is not to install a barrier. A tree whose roots are already under the slab may be better served by repairing the paving, or the tree may be a candidate for removal.
Before the trench
- Call 811 so buried lines are marked
- Have the arborist identify which roots matter to the tree's stability
- Decide what you are protecting: a walk, a sewer lateral, a foundation or a pool
- Compare against alternatives: a re-routed path, a flexible paving fix, or a smaller species next time
- Ask what the barrier will not do, and get that in the estimate
Next step
For a site visit, ask for a free estimate. Our root barriers page lists the service, and our guide to roots, sidewalks and sewer lines covers the cause side. Battle Born Tree Service has two ISA Certified Arborists on staff, including ISA Certified Arborist WE-11728A.
Sources
- International Society of Arboriculture, Trees Are Good: Avoiding Tree and Utility Conflicts (read October 17, 2026)
- University of Nevada, Reno Extension: Tips for Healthy Landscape Trees (read October 17, 2026)
- International Society of Arboriculture, Trees Are Good: Why Hire an Arborist (read October 17, 2026)