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Ground-Penetrating Radar (GPR) locates objects underground without excavations or ground disturbance.
Ground-Penetrating Radar (GPR) locates objects underground without excavations or ground disturbance.
For over 30 years GPR has been used to locate engineering and environmental targets and, map the subsurface profile.
Ground Radar operates by emitting an electromagnetic wave from an antenna - as the signal encounters a boundary between inert matter with different electromagnetic properties it reflects, refract, and/or diffract from the periphery in a predictable manner. “TreeRadar” GPR operates similarly.
“TreeRadar” GPR operates similarly detecting electromagnetic contrasts in boundaries between roots and soil.
“TreeRadar” GPR operates similarly detecting electromagnetic contrasts in boundaries between roots and soil.
Dead roots have a lower moisture content and do not have sufficient electromagnetic differences to the soil matrix to be detected. Dead roots are defined as none active decedent roots of more than 12 months.
The scanning process
The scanning process
The antenna is coupled to ground-measuring mechanism. This enables the distance along the scanline and depth of the roots to be plotted to the radargrams.
Fixed locational points (synchronisation lines) are also plotted to provide facility for mapping root locations to scaleable plans .
For tree root plotting two types of antennae are used
For tree root plotting two types of antennae are used
- A 400 MHz antenna , this scans to around 2.5 metre depth. The 400 MHz antennae targets tree roots over 20mm diameter and above.
- A 900 MHz antenna scans to 1 metre depth targeting roots 10mm diameter and above
A field computer collects data on site:
A field computer collects data on site:
The data is downloaded for processing by analysis software TreeWin TBA. There are two stages:
1st Stage analysis data outputs :
- Scaled “trench face” visual radargrams.
2nd Stage analysis data outputs :
- Top Down View or plan view root position charts
- Root morphology maps
1st Stage analysis - Trench face” visual (radargrams)
1st Stage analysis - Trench face” visual (radargrams)
“Trench face” visual (radargrams)
“Trench face” visual (radargrams)
These provide a scaled spatial view below the scan line and display the depth and distance of roots in a virtual trench face.
There is a distance scale along the top, and depth scale down the left axis. The green broken lines in are fixed site marker points [Walls, tree, etc].
2nd Stage analysis - Top Down View Root Positions
2nd Stage analysis - Top Down View Root Positions
Top Down View (TDV) root positions
Top Down View (TDV) root positions
TDVs give an indication of root positions along the scan lines and provide a visual indication of high/low root densities/root free zones in plan-view.
TDV root position/density plots can be mapped to site plans to show root positions and densities against site features and to scale.
2nd Stage analysis - Root Morphology Mapping
2nd Stage analysis - Root Morphology Mapping
Root morphology maps
Root morphology maps
Root morphology maps provide a detailed plan view of the spread and density of roots.
For circular or partial radial scanline surveys, morphology maps are generated by the bespoke software.
Additionally, Peter Barton Associates uniquely generate morphology maps from linear scanlines, using the data from TDV outputs.
On sites with woody plants as well as trees "high root density hot-spots" are also predicted as shown right.
Tree Root Development - Dispel the Myths
Tree Root Development - Dispel the Myths
With over a decade of TreeRadar experience our investigations show that Tree root development follows predictable patterns.
Root densities are lower near the base of trees
Root densities are lower near the base of trees
These are buttress roots etc; roots then proliferate with radial distance from the tree with an increase in root numbers and density.
In the below ground spatial depth profile, roots exploit a 70cm to 90cm band width depending on ground conditions. Very few roots over 20 mm diameter are normally found in the top 40cm – 60cm soil depth.
Variations are associated with soil type and tree species.
Peter Barton Associates forensic investigation services: we are experienced in assessing tree root damage and root plate integrity verifying our findings with TreeRadar data outputs
Peter Barton Associates forensic investigation services: we are experienced in assessing tree root damage and root plate integrity verifying our findings with TreeRadar data outputs
Peter Barton Associates experience:
Peter Barton Associates experience:
- provides for definitive assessments on damage to root systems , root trespass and root plate integrity.
The Radargram montage to the right show the extent of root damage to a group of limes where contractors cut into the root plate to instal a car park.
The results of our investigations indicated that when compared to undisturbed root zone, around 50% live roots remained under the car park.
Advice was given on monitoring tree health, recovery and risk hazard assessment.
For more information please contact Peter Barton as below:
For more information please contact Peter Barton as below:
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