Tree roots sometimes need to be removed when they interfere with infrastructure, such as lifting sidewalks or invading underground pipes. While trees are resilient, improper root removal can cause significant damage to the plant or surrounding property. This guide outlines the steps necessary to safely and effectively cut tree roots while minimizing harm to the parent tree and resolving conflicts between root growth and built environments.
Preparation and Safety First
Before cutting, ensuring safety and compliance with local regulations is paramount. In the United States, anyone planning to dig must first call 811 to have all underground utility lines marked. This prevents accidental contact with gas, water, or electrical infrastructure, protecting the worker and the property from costly damage or injury.
Once the area is clear of utilities, the root intended for removal must be fully exposed to determine its origin and size accurately. Hand-digging with a trowel is effective for smaller areas. For larger projects, specialized equipment such as an air spade or hydro excavation can safely remove soil using pressurized air or water without physically damaging the root structure.
Full exposure allows for the identification of structural roots. These are large, woody roots near the base of the tree that provide mechanical stability. Cutting a structural root, especially if it exceeds two inches in diameter or is within the tree’s dripline, can destabilize the plant and make it prone to windthrow. If the root appears large and close to the trunk, consult a certified arborist to assess the risk before proceeding.
Tools and Techniques for Cutting
The selection of the cutting tool depends on the root’s diameter and location. Small feeder roots, typically less than half an inch in diameter, can be severed cleanly using hand pruners or loppers. For medium-sized roots up to two inches thick, a sharp hand saw or a specialized root cutter provides the necessary leverage for a clean cut.
For roots larger than two inches, a powered reciprocating saw fitted with a specialized blade designed for wood and roots reduces the effort required. Chainsaws pose a substantial risk of kickback and are generally not recommended for ground-level root work unless handled by an experienced professional. Ensuring the blade is sharp minimizes splintering and tearing, which reduces the surface area available for pathogen entry.
The physical act of cutting must be executed with precision to maximize the tree’s ability to compartmentalize the wound. The cut should be made perpendicular to the root’s axis, creating a smooth, clean face rather than an angled or jagged one. This clean, 90-degree cut allows the tree to form a callus and seal the wound more efficiently, a process known as Compartmentalization of Decay in Trees (CODIT).
A primary technique involves cutting the root as far away from the tree trunk as possible while still achieving the desired clearance from the encroached structure or pipe. For example, when roots invade a sewer line, the cut should be made several feet away from the pipe’s entry point to allow for barrier installation. Removing only the segment causing interference preserves a greater portion of the tree’s root system, reducing overall stress on the plant.
Managing the Tree’s Health After Cutting
After severing the unwanted root segment, monitoring the parent tree for signs of stress is important. Signs of distress include leaf yellowing (chlorosis) or the premature dropping of foliage, indicating reduced water and nutrient uptake. Providing supplemental irrigation during dry periods in the following two years helps the tree compensate for the loss of the severed root’s absorptive capacity.
Contrary to outdated gardening advice, cut root ends should not be treated with wound paint or sealing compounds. These barriers can trap moisture, creating an environment favorable for fungal and bacterial growth, which inhibits the tree’s natural healing process. The tree’s internal defense mechanisms are most effective when the cut is left exposed to air, allowing it to naturally form a protective barrier.
To prevent future root issues, implementing a physical root barrier is the most effective long-term solution. These barriers, often made of high-density polyethylene or fiberglass, must be installed vertically into the ground to a depth of at least thirty inches. This diverts new root growth downward and away from the problem area. The barrier should be placed a suitable distance from the structure or pipe to allow roots to grow around the obstacle.
As an alternative, particularly for roots repeatedly invading sewer lines, chemical root inhibitors can be applied after physical removal. These products typically contain copper sulfate or a similar compound that slows the growth of new root cells. While effective for localized control, chemical methods require careful application to avoid harming non-target plants and are generally a short-term management strategy compared to permanent physical barriers.