Resistograph Decay Detection Testing

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Planning Permssion

The local authority tree officer may require the information as part of your submission, or alternatively may have requested the information as a condition.

health and safety

Our assessment will recommend any tree work that we consider necessary on health and safety grounds or where it cannot be avoided to remove part or all the tree to enable a better planning application.

Impact of Trees

A BS 5837 Tree Survey is an important element to know exactly what Trees have an impact on the proposed development and that the development will have on them.


Where trees need to be removed, we will always like to ensure suitable replacements are provided as mitigation. This will provide a continuity of tree cover.

Are you looking for a Resistograph decay detection test for your trees.  This is an invasive assessment using a microdrill to measure the resistance of the wood.

We at Arbor Cultural Ltd. have just invested in a new IML RESI-PD400.  This new specialist instrument is designed not just for an accurate measurement of the resistance given by wood to drilling (torsional resistance), but also an accurate measurement of the pushing force required to penetrate the tree stem.

This can be used as a tool to determine the strength loss of a stem or branch, to help determine whether it can be retained, and whether any form of tree surgery is required.

Resistance to drilling by wood is not a complete measure of wood strength, but resistance is usually significantly reduced if wood is weakened by decay.

The additional measure of the pushing force incorporated into this new device is important as it assists in the measurement of some structural loss due to certain types of decay, which were not so evident from just the rotational measurement.

Arbor Cultural Ltd are able to assist you with all these aspects to enable you to address your tree concerns.

Both of these readings are displayed on a digital readout on the top of the device, which can be exported as a graphical image into a report.

This device is used to excavate a narrow penetration track with a fine drill where decay is suspected. The IML RESI-PD400 has a drill diameter of approximately 3mm and a drill length of 400mm.

The RESI drill bit causes minimal damage as it is of very small diameter which leaves a narrow penetration track. It also does not remove the wood fragments when extracted.

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Frequently asked questions

Why are Tree Reports Required?

These BS5837 elements are all important for a smooth and successful planning process. The local authority tree officer can ask for any or all of these to better enable him to assess your planning application.

What Reports are available