Trees are dynamic structures, constantly growing and changing to adapt to environmental conditions. Therefore it is critical that tree owners and managers take appropriate action to maintain their safety. Managers and land owners have a ‘Duty of Care’ to take reasonable care under the Occupiers Liability Acts 1957 and 1984 to ensure that trees situated on their land remain in a safe condition as far as it reasonably practicable.  Wharton Tree & Ecology Consultants can undertake a variety of survey methods to discharge this obligation.

Due to their potential large size and proximity to frequently used areas mean that trees can pose a risk to nearby people and property. Although tree-related fatalities are very rare, tree owners have a legal responsibility to ensure their trees do not pose an unacceptable risk.  The National Tree Safety Group has published further guidance for landowners which can be read here.


The frequency and detail of a tree survey can vary from a less detailed “walk through survey” to a highly detailed “individual tree survey”.  Surveys are individually tailored to meet specific requirements of each client and following relevant guidance of the National Tree Safety Groups (NTSG) and Lantra.

Information collected from individual tree inspections to large scale tree surveys are correlated and recorded using the latest technology in computerised tree management software, GPS (Global Positioning Systems) and GIS (Geographic Information Systems).  This ensures that trees are accurately plotted and all information is systematically ascertained for all trees.  We will work with all clients to ensure that data captured is relevant to individual requirements.

As an output to our tree inspections and surveys all clients are provided with a detailed tree schedule, site plan and report in a format of your choice, which is often provided electronically to reduce cost and the use of paper. We also provide tree management strategies and policies depending on the land owners requirements.

All of our consultants and associates who undertake visual tree assessments (VTA) and inspections hold the Lantra Awards Certificate for Professional Tree Inspections. This is an industry recognised certification to ensure inspectors are arboriculturally qualified and competent.


The Quantified Tree Risk Assessment (QTRA) system applies established and accepted risk management principles to tree safety management.

The system moves the management of tree safety away from labelling trees as either ‘safe’ or ‘unsafe’ and thereby away from requiring definitive judgements of either tree surveyors or tree managers. Instead, QTRA quantifies the risk of significant harm from tree failure in a way that enables tree managers to balance safety with tree values and operate to a predetermined limit of reasonable or acceptable risk.

Wharton Tree & Ecology Consultants is a Licensed User of QTRA, which is implemented where appropriate.  Additionally Wharton Tree & Ecology Consultants also implements other hazard rating systems where the use of QTRA is not considered appropriate.  Alternative solutions follow industry best practice and guidance will be discussed with clients prior to any formal instruction.


In addition to initial external assessment of a tree, if there is internal decay suspected or decay causing organisms identified, it may be necessary to undertake a further internal examination. Wharton Tree & Ecology Consultants currently has an IML PD400 resistograph to assess decay. We also have access to a variety of other tools. This will assess the extent of decay and provide additional information to evaluate and aid the decision making process to ensure the most appropriate remedial action is undertaken.

Using the latest decay detection tools from IML, we are able to assess the extent of any cavities or decay internally to the tree using a microdrill resistograph. Our resistograph PD400 uses a fine needle to drill into the stem or other part of the tree. Two sensors on the drill measure the power required to maintain the drill turning at a constant speed, and the pressure being applied to the top of the drill. The output of the sensors is recorded in graphical form and from these we are able to make an assessment as to the extent and location of any cavities. The use of such technology can assist in the decision making process for the management of potentially hazardous trees.

Following quantification and mapping of internal decay an appraisal of the tree using modern research and current industry best-practice will ensure the correct prognosis and recommendations are made.


In general all of our tree inspection work is undertaken from ground level, however, where required detailed aerial inspections are undertaken particularly of over-mature and veteran trees.

This type of inspection would be commissioned where there are large wounds, cavities or splits associated with trees or following the identification of decay or decay causing organisms.  This work is generally recommended following the initial ground level survey.


Wharton Tree & Ecology Consultants does not undertake in-house tree surgery.  We believe this allows an impartial and unbiased assessment, with only the best interests of the client and subject trees at the heart of all recommendations.

Following a tree survey we can, at the client’s request, facilitate quotations, contracts, or specifications from a variety of established contractors to undertake remedial work as necessary.

Wharton Tree & Ecology Consultants has considerable experience in supporting managers of significant sites with high levels of public access. We are able to aid the development and implementation of policy in order that the landowner or manager can meet their ‘duty of care’ with regard to both public safety and their environmental policy.

Wharton Tree & Ecology Consultants is a dedicated team of professionals who consistently deliver proven successes through education & a solid foundation of knowledge & experience.


“Worcester City Council employed the services Wharton Tree & Ecology Consultants to carry out decay detection on a number of mature trees lime trees. The service and report they provided was prompt, detailed  and to a high standard. The findings allowed  the Council to take an informed decision on how to manage trees on a land mark site in Worcester City.”

Oliver Kaye, Worcester City Council



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