Arborist OnSite® uses Ground Penetrating Radar technology for tree root mapping.

root imaging
These pink markers in the ground are the proposed locations for below-ground footing piers. All are within the drip-line of these oak trees. As we pushed the antenna over each one we stopped and put a marker on the field computer to identify its location. The information we need to know is what kind of root structure is below each pink marker.

Introduction to Ground-Penetrating Radar (GPR)

Ground-Penetrating Radar (GPR) is an established technique that has been used worldwide for over 40 years to locate objects underground, including pipes, barrels, drums, and other engineering and environmental targets. When an electromagnetic wave emitted from a small surface transmit antenna encounters a boundary between objects with different electromagnetic properties it will reflect, refract, and/ or diffract from the boundary in a predictable manner. Electromagnetic differences between tree roots and the surrounding soil matrix provide the necessary contrast and reflection properties that are detected by GPR.

  • root mapping
  • root inspection procedure
  • Locating oak tree roots, for placement of a storage tank below ground
    Locating oak tree roots, for placement of a storage tank below ground.
  • tree root mapping
  • tree root mapping
  • root scanning inside a house
    Scanning inside a house
  • scanning roots through rubber sidewalk
    Scanning rubber sidewalk

Ways Our Clients Have Benefitted from GPR

  1. Isolating foundation damage from invasive tree roots.
  2. Determining root location and density at construction sites for protected trees.
  3. Determining the actual drip-line of trees for protection at construction sites.
  4. Placement of swimming pools, leach lines and pipes to minimize root damage to existing trees.
  5. Determining location placement of construction piers between lateral root systems for foundation or retaining wall construction.
  6. Trenching near protected trees, knowing where and where not to dig.
  7. Existing sidewalk, curb or driveway replacement, preventing root damage.
  8. Determining root density and depth to evaluate a tree’s stability.
  9. Determining root density for placement of below ground tanks or equipment near protected trees.
  10. Litigation cases such as trip and fall, involving raised concrete sidewalks and tree roots.
top-down root diagram
This is a conceptual 3D Top-Down diagram of what the root structure may look like below ground. The software uses the results of the predicted root locations from five half circle scans generated from the virtual trench data and connects the dots, creating what you see on this page. This provides a visualization concept of what the root structure may look like below ground.

Advantages of Ground-Penetrating Radar as a method of mapping tree roots over other methods of root locating

  1. It is capable of scanning root systems of large trees under field conditions.
  2. It is completely non-invasive and does not disturb the soils or damage the trees examined, and causes no harm to the environment.
  3. Being non-invasive, it allows repeated measurements that reveal long-term root system development.
  4. It allows observation of root distribution beneath hard surfaces (concrete, asphalt, bricks), roads and buildings.
  5. Its accuracy is sufficient to resolve structural roots with diameters from less than 1 cm (0.4 in) to 3 cm (1.2 in) or more.
  6. It can characterize roots at both the individual tree and stand levels, facilitating correlations with tree-and stand-level measurements of physiological processes (e.g., sap flow) in complex ecological studies.

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