Tree Roots, Trees & Utilities Near Excavations
Digging near a tree can cut major roots, weaken the tree and make it fall onto the crew or a neighbor. Roots also grow into pipes and wrap around utilities, hiding them. Planning protects the people, the tree and the buried lines.
- Excavation
- Landscape & Utilities
- Homeowners
Hazards
- Tree failure: trenching near the trunk or cutting large roots can destabilize the tree. It may fall without warning, even days later.
- Trench collapse where roots and loose soil give poor support. See Trenching Basics.
- Hidden utilities tangled with roots. Always call 811. See Call 811 and Utility Strikes.
- Struck-by from falling limbs, equipment and cut roots under tension.
- Chainsaw and tool hazards when cutting roots. See Landscaping & Tree Work.
- Damage to pipes from root intrusion, and to roots from pipe repairs.
Plan before digging
- Call 811 and mark utilities; consider the private lines the locate does not cover. See Private Utility Locating
- Look at the tree: lean, dead branches, cracks, fungi, recent damage, soil heave
- Ask a certified arborist to assess valuable or large trees and advise how far from the trunk to dig (a common rule of thumb is a distance of several times the trunk diameter, though it varies)
- Check permits and rules for protected trees
- Choose methods that avoid roots: hand digging, directional drilling or hydro or air excavation. See Hydro-Vacuum Excavation and Directional Drilling
Working around roots
- Keep the crew out of the fall zone of a tree that may be unstable. Evacuate if the tree moves or cracks.
- Expose roots by hand or with vacuum, and cut roots cleanly with sharp tools (pruners, saws) rather than ripping them with machines. Avoid cutting large structural roots.
- Tunnel under major roots when possible instead of cutting.
- Support the trench walls with a trench box or shoring. Roots do not make a trench safe. See Protective Systems.
- Backfill carefully and keep the root zone from being compacted by equipment.
- Watch the tree afterward and report signs of decline or lean.
Standards & references
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